Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

Judging from your data, the pot takes the oven from at or above the inflection 
temperature of the crystal down to a point well below the crystal’s lower turn 
temperature. That’s about all it needs to do. 

Bob

> On Mar 11, 2016, at 11:19 PM, time...@metachaos.net wrote:
> 
>> Hi
> 
>> Anything electrical (duty cycle/ harmonics / output level / etc) 
>> is designed in on a modern part done in high volume. 
> 
>> The only candidates for a pot on top of the oven are:
> 
>> Inner oven temperature
>> Outer oven temperature
>> EFC
> 
>> You have already ruled out EFC (it would be a coarse set so
>> visible on a normal counter). 
> 
>> That leaves inner oven and outer oven. 
> 
>> Why inner oven - to adjust for the data from your temperature run. The parts
>> are at best coarse set based on crystal temperature. 
> 
>> Why outer oven - same as above or to set for inner / outer separation
>> and clearance after the thermal stabilization in the sealed can. 
> 
>> If there is no apparent change in frequency (and from the location of
>> the pot) that suggests the outer oven. Regardless of which oven is being 
>> set, the
>> adjustment is likely a “move it 1.25 turns" sort of thing.  You then 
>> re-run the temperature test to see if it is in spec yet. 
> 
>> Bob
> 
> 
> Bob,
> 
> In a separate communication, Angus has stated...
> 
>> On the two that I tested, it appeared to adjust the temperature of
>> both of the ovens.
> 
>> One was a 5 MHz 260-0545-B. The outer oven was at 78.2 degC and at
>> least around that point the temp changed at about 1 degC per turn. The
>> EFC adjustment on this one was not quite enough to bring the frequency
>> to exactly 5 MHz, but the oven temp did look to be close to correct.
> 
>> The other was a 16.384 MHz 260-0546-G which was unused old stock, but
>> had overall poor stability. It turned out that the oven temp on it was
>> 1-3/8 turns from the turnover point, but when or how that happened I
>> don't know.
> 
>> It would be interesting to hear from somebody who knows how this type
>> of thing is actually adjusted in production.
> 
> I finally got my 260 (sort of) repaired and have done some measurements.
> 
> Generally, I can confirm what Angus was saying, to the limits of my ability to
> measure. One of the things that I can measure is the source voltage. I have a
> hacked together 12v supply. When hooked up to the 260, it initially reads just
> over 9v. As it warms up, it eventually tops out just under 10v. There appears
> to be roughly four different points, around 9.1v, 9.35v, 9.8v and 10v. The 260
> starts at around 9.1v, quickly moves up to 9.35v and after a while to 9.8v. It
> will then sometimes move briefly up to 10v and back down to 9.8v.
> 
> I interpret this as different heating stages - probably both ovens on, one
> oven on, some sort of maintenance heating point and no heaters on.
> 
> What I find as I adjust the pot (after letting the 260 warm up) is that
> turning the pot counter clockwise the supply voltage will go up to 10v and
> turning it clockwise it will drop to 9.35v or 9.1v. So, from that it would
> appear that you are right in that the temperature set points are being
> adjusted by the pot. Whether only one is adjusted or both are changed as Angus
> says isn't clear.
> 
> I also noticed that the 260 consistently has an adjustment range of +/-2e-7,
> regardless of where the frequency is set, with 0v applied to the adjustment
> pin giving a frequency 4Hz higher than when the 5.65v reference voltage is
> applied to the adjustment pin. It will adjust further if the reference pin is
> hooked up to the supply voltage.
> 
> So, I decided to get as much information as I could. I turned the pot
> clockwise until it "ticked" once each turn. That dropped the temperature to
> the minimum. I then turned it counter clockwise 1/2 turn at a time and
> recorded each temperature / frequency reading. I did this until it "ticked"
> once each turn. That took nearly three days. To obtain the temperature, I
> used Kapton tape to tape a temperature sensor for my multimeter to the casing
> of the outer oven. This is not necessarily the hottest spot, nor does it
> actually measure the temperature in either the inner or outer oven. Further,
> the multimeter's precision is only around 1 degree C. The accuracy is unknown,
> but it should be repeatable and roughly linear. I used my (uncalibrated)
> 2465BCT to measure the frequency. This is limited to 7 digits without a
> calibrated frequency standard and is probably slightly off. Still, that gave
> me a good bit of data. Here is the raw data.
> 
>   605.01
>   615.02
>   615.03
>   625.03
>   625.04
>   635.05
>   635.06
>   645.06
>   655.07
>   655.08
>   665.08
>   665.09
>   675.09
>   675.10
>   685.10
>   695.10
>   705.11
>   715.11
>   725.12
>   735.12
>   74

Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

> Hi

> Anything electrical (duty cycle/ harmonics / output level / etc) 
> is designed in on a modern part done in high volume. 

> The only candidates for a pot on top of the oven are:

> Inner oven temperature
> Outer oven temperature
> EFC

> You have already ruled out EFC (it would be a coarse set so
> visible on a normal counter). 

> That leaves inner oven and outer oven. 

> Why inner oven - to adjust for the data from your temperature run. The parts
> are at best coarse set based on crystal temperature. 

> Why outer oven - same as above or to set for inner / outer separation
> and clearance after the thermal stabilization in the sealed can. 

> If there is no apparent change in frequency (and from the location of
> the pot) that suggests the outer oven. Regardless of which oven is being set, 
> the
> adjustment is likely a “move it 1.25 turns" sort of thing.  You then 
> re-run the temperature test to see if it is in spec yet. 

> Bob


Bob,

In a separate communication, Angus has stated...

> On the two that I tested, it appeared to adjust the temperature of
> both of the ovens.

> One was a 5 MHz 260-0545-B. The outer oven was at 78.2 degC and at
> least around that point the temp changed at about 1 degC per turn. The
> EFC adjustment on this one was not quite enough to bring the frequency
> to exactly 5 MHz, but the oven temp did look to be close to correct.

> The other was a 16.384 MHz 260-0546-G which was unused old stock, but
> had overall poor stability. It turned out that the oven temp on it was
> 1-3/8 turns from the turnover point, but when or how that happened I
> don't know.

> It would be interesting to hear from somebody who knows how this type
> of thing is actually adjusted in production.

I finally got my 260 (sort of) repaired and have done some measurements.

Generally, I can confirm what Angus was saying, to the limits of my ability to
measure. One of the things that I can measure is the source voltage. I have a
hacked together 12v supply. When hooked up to the 260, it initially reads just
over 9v. As it warms up, it eventually tops out just under 10v. There appears
to be roughly four different points, around 9.1v, 9.35v, 9.8v and 10v. The 260
starts at around 9.1v, quickly moves up to 9.35v and after a while to 9.8v. It
will then sometimes move briefly up to 10v and back down to 9.8v.

I interpret this as different heating stages - probably both ovens on, one
oven on, some sort of maintenance heating point and no heaters on.

What I find as I adjust the pot (after letting the 260 warm up) is that
turning the pot counter clockwise the supply voltage will go up to 10v and
turning it clockwise it will drop to 9.35v or 9.1v. So, from that it would
appear that you are right in that the temperature set points are being
adjusted by the pot. Whether only one is adjusted or both are changed as Angus
says isn't clear.

I also noticed that the 260 consistently has an adjustment range of +/-2e-7,
regardless of where the frequency is set, with 0v applied to the adjustment
pin giving a frequency 4Hz higher than when the 5.65v reference voltage is
applied to the adjustment pin. It will adjust further if the reference pin is
hooked up to the supply voltage.

So, I decided to get as much information as I could. I turned the pot
clockwise until it "ticked" once each turn. That dropped the temperature to
the minimum. I then turned it counter clockwise 1/2 turn at a time and
recorded each temperature / frequency reading. I did this until it "ticked"
once each turn. That took nearly three days. To obtain the temperature, I
used Kapton tape to tape a temperature sensor for my multimeter to the casing
of the outer oven. This is not necessarily the hottest spot, nor does it
actually measure the temperature in either the inner or outer oven. Further,
the multimeter's precision is only around 1 degree C. The accuracy is unknown,
but it should be repeatable and roughly linear. I used my (uncalibrated)
2465BCT to measure the frequency. This is limited to 7 digits without a
calibrated frequency standard and is probably slightly off. Still, that gave
me a good bit of data. Here is the raw data.

   605.01
   615.02
   615.03
   625.03
   625.04
   635.05
   635.06
   645.06
   655.07
   655.08
   665.08
   665.09
   675.09
   675.10
   685.10
   695.10
   705.11
   715.11
   725.12
   735.12
   745.12
   755.12
   765.12
   765.13
   775.13
   785.12
   795.12
   805.12
   815.12

Here is a rough graph. It shows the expected SC temperature / frequency type
of curve. However, what is interesting is the range over which adjusting the
temperature affects the frequency. This is a total of 12Hz! Also, it should be
noted that the outer case was not in place, so the outer oven is 

Re: [time-nuts] MTI 260-0624-D OCXO

[Magnus Danielson]

Mike,

Ouch!

Not opening before they say OK seems like a good strategy.

I just wanted to share that little story even if it doesn't help you.
It was worse when I got a BVA with *crushed* thermo-flask. I was 
actually given a replacement thermo-flask within a few days from OSA.


Cheers,
Magnus

On 03/06/2016 02:15 AM, time...@metachaos.net wrote:

Magnus,

In this case, the rattle is not of light weight pieces, but of a heavy object.
So, I am guessing that the outer oven broke off somehow. Won't really know
until and unless I open it up. The vendor probably won't want it back, but
they might, so I won't touch it until I hear from them.


Mike


Hi,



On 03/05/2016 10:45 PM, time...@metachaos.net wrote:

I got the replacement MTI 260-0624-D OCXO today.

It rattles!



I've seen that on one oscillator. I did a RMA and complained about the
maracas mode, which I had demonstrated to the rep. When it arrived they
wondered what that mean and the rep just smiled and ask them to pick it
up... and it rattle. Turns out that the way they soldered their ovens,
drops of solder could form and get loose, so they changed the process.



Unfortunatly, it is also the failure mode of rough shipping/handling for
some oscillators.



Cheers,
Magnus



I didn't even bother trying to power it up. Not much point. I have not taken
it apart, but have notified the seller. I may disassemble this one as well,
depending on what the seller says.

Mike



I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
it is clear that it is defective.



 1. It never heats up.



 2. The reference voltage is zero.



 3. Only noise is seen on the output pin.



I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
be sufficient to test.



All I was looking for was a 5Mhz signal whose frequency changed when the
adjustment pin was either tied to ground or the reference voltage. Never got
that far because I never go a signal at all.



The seller packed it well and shipped it promptly. I will see how he handles
it.




Mike



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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

Magnus,

In this case, the rattle is not of light weight pieces, but of a heavy object.
So, I am guessing that the outer oven broke off somehow. Won't really know
until and unless I open it up. The vendor probably won't want it back, but
they might, so I won't touch it until I hear from them.


Mike

> Hi,

> On 03/05/2016 10:45 PM, time...@metachaos.net wrote:
>> I got the replacement MTI 260-0624-D OCXO today.
>>
>> It rattles!

> I've seen that on one oscillator. I did a RMA and complained about the 
> maracas mode, which I had demonstrated to the rep. When it arrived they 
> wondered what that mean and the rep just smiled and ask them to pick it 
> up... and it rattle. Turns out that the way they soldered their ovens, 
> drops of solder could form and get loose, so they changed the process.

> Unfortunatly, it is also the failure mode of rough shipping/handling for 
> some oscillators.

> Cheers,
> Magnus

>> I didn't even bother trying to power it up. Not much point. I have not taken
>> it apart, but have notified the seller. I may disassemble this one as well,
>> depending on what the seller says.
>>
>> Mike
>>
>>
>>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing 
>>> it,
>>> it is clear that it is defective.
>>
>>> 1. It never heats up.
>>
>>> 2. The reference voltage is zero.
>>
>>> 3. Only noise is seen on the output pin.
>>
>>> I tested with a 12.54V, 2A supply voltage with around 30mV noise. That 
>>> should
>>> be sufficient to test.
>>
>>> All I was looking for was a 5Mhz signal whose frequency changed when the
>>> adjustment pin was either tied to ground or the reference voltage. Never got
>>> that far because I never go a signal at all.
>>
>>> The seller packed it well and shipped it promptly. I will see how he handles
>>> it.
>>
>>
>>> Mike
>>
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
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>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
>>
>>
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-- 
Best regards,
 Timenutmailto:time...@metachaos.net

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Re: [time-nuts] MTI 260-0624-D OCXO

[Magnus Danielson]

Hi,

On 03/05/2016 10:45 PM, time...@metachaos.net wrote:

I got the replacement MTI 260-0624-D OCXO today.

It rattles!


I've seen that on one oscillator. I did a RMA and complained about the 
maracas mode, which I had demonstrated to the rep. When it arrived they 
wondered what that mean and the rep just smiled and ask them to pick it 
up... and it rattle. Turns out that the way they soldered their ovens, 
drops of solder could form and get loose, so they changed the process.


Unfortunatly, it is also the failure mode of rough shipping/handling for 
some oscillators.


Cheers,
Magnus


I didn't even bother trying to power it up. Not much point. I have not taken
it apart, but have notified the seller. I may disassemble this one as well,
depending on what the seller says.

Mike



I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
it is clear that it is defective.



1. It never heats up.



2. The reference voltage is zero.



3. Only noise is seen on the output pin.



I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
be sufficient to test.



All I was looking for was a 5Mhz signal whose frequency changed when the
adjustment pin was either tied to ground or the reference voltage. Never got
that far because I never go a signal at all.



The seller packed it well and shipped it promptly. I will see how he handles
it.




Mike



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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

Where (what continent) was the seller located?

Bob


> On Mar 5, 2016, at 4:45 PM, time...@metachaos.net wrote:
> 
> I got the replacement MTI 260-0624-D OCXO today.
> 
> It rattles!
> 
> I didn't even bother trying to power it up. Not much point. I have not taken
> it apart, but have notified the seller. I may disassemble this one as well,
> depending on what the seller says.
> 
> Mike
> 
> 
>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing 
>> it,
>> it is clear that it is defective.
> 
>>   1. It never heats up.
> 
>>   2. The reference voltage is zero.
> 
>>   3. Only noise is seen on the output pin.
> 
>> I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
>> be sufficient to test.
> 
>> All I was looking for was a 5Mhz signal whose frequency changed when the
>> adjustment pin was either tied to ground or the reference voltage. Never got
>> that far because I never go a signal at all.
> 
>> The seller packed it well and shipped it promptly. I will see how he handles
>> it.
> 
> 
>> Mike
> 
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
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>> and follow the instructions there.
> 
> 
> 
> -- 
> Best regards,
> Timenutmailto:time...@metachaos.net
> 
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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

I got the replacement MTI 260-0624-D OCXO today.

It rattles!

I didn't even bother trying to power it up. Not much point. I have not taken
it apart, but have notified the seller. I may disassemble this one as well,
depending on what the seller says.

Mike


> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
> it is clear that it is defective.

>1. It never heats up.

>2. The reference voltage is zero.

>3. Only noise is seen on the output pin.

> I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
> be sufficient to test.

> All I was looking for was a 5Mhz signal whose frequency changed when the
> adjustment pin was either tied to ground or the reference voltage. Never got
> that far because I never go a signal at all.

> The seller packed it well and shipped it promptly. I will see how he handles
> it.


> Mike

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-- 
Best regards,
 Timenutmailto:time...@metachaos.net

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Re: [time-nuts] MTI 260-0624-D OCXO

[Angus]

On Sat, 20 Feb 2016 14:56:47 -0500, you wrote:

>I think that there are a lot of unexplored possibilities, but I definitely am
>not convinced that it sets either the inner or outer oven temperature. There
>are simply better ways to do that in production.

Hi Mike,

On the two that I tested, it appeared to adjust the temperature of
both of the ovens.

One was a 5 MHz 260-0545-B. The outer oven was at 78.2 degC and at
least around that point the temp changed at about 1 degC per turn. The
EFC adjustment on this one was not quite enough to bring the frequency
to exactly 5 MHz, but the oven temp did look to be close to correct.

The other was a 16.384 MHz 260-0546-G which was unused old stock, but
had overall poor stability. It turned out that the oven temp on it was
1-3/8 turns from the turnover point, but when or how that happened I
don't know.

It would be interesting to hear from somebody who knows how this type
of thing is actually adjusted in production. 

Angus.


>> If this is a double oven, there are two oven circuits and two oven 
>> controllers.
>> Both would have a set point and both would be adjusted somehow. The pot
>> may be the adjustment on the outer oven. Get things all set up and packaged,
>> then adjust the outer oven to make things do what the should do.
>
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

On an entirely different project, I happened to get diverted over to “ZVS 
modules”. 
They are the guts of an induction heater and are dirt cheap (as in less than 
the price
of the OCXO). More or less, it’s the 3’ rack cabinet from 1935 done as solid 
state for 
$10 to $50. 

If you had several parts to open, I suspect you could rig up a very nice custom 
“can opener”
for not a lot of money. 

I have no idea how well these modules work or if they need liquid nitrogen 
cooling to operate
for more than 100 ms. It does look interesting. 

Bob 

> On Feb 20, 2016, at 1:18 PM, d...@irtelemetrics.com wrote:
> 
> For anyone interested to know an induction heater, If you happen to have one 
> laying around,
> works pretty well for opening these types of cans up. Properly placed you can 
> heat the can
> melt the solder and not burn up any paper labels on the top of the can. If 
> done carefully, they
> can be reassembled this way also.  
> My guess is even the cheap inductive cook tops would work for this.  
> Dan
>  
>  
>  
> 
> I have read sometime ago and probably on this list a success stories
> about opening OCXOs using a hot air gun or even a propane torch, an
> x-acto knife and a stainless steel shim sheet to avoid the solder to do
> it stuff again when solidifying. Using this technique probably the can could 
> be reused after repairing
> the part. 
> Ignacio EB4APL
> 
> 
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Re: [time-nuts] MTI 260-0624-D OCXO

[Adrian]

Mike,

the most likely use of that mysterious pot is for final frequency
adjustment.
You might just not have measured with sufficient resolution.

I agree with you that the oven temperature theory makes not overly much
sense.
If you want to know for sure, you may check what the pot is connected to.

Adrian

time...@metachaos.net schrieb:
> Bob,
>
> I still have a problem with the various theories. Again, how is it measured?
> If you have a production line, you don't want a "tweak" that requires hours or
> days to determine.
>
> As far as setting the crystal set point (presumably the inner over set point),
> that makes even less sense. Consider that they clearly knew the turn over
> point of the crystal BEFORE it was packaged. They wrote it on the sticker 
> inside.
> So, they would have no need to adjust the inner oven. That could easily have
> been done on the bench during assembly. It could also be done via a selection
> from a standardized set of components. That temperature is "sort of" critical.
> The curve is very flat, to it could be a little off. Since they knew the
> crystal turn over point in advance, there wouldn't be any need to "hunt" for
> it by an elaborate procedure after assembly.
>
> However, the temperature of the outer oven is much less critical and I would
> suspect is simply set by the choice of components. And, if it needed tweaking
> then it could also have been done on the bench. Since they would know the
> thermal transfer characteristics, I suppose that they could measure the outer
> case's temperature to deduce the correct temperature of the outer oven. But,
> again, that doesn't make sense from a production standpoint. It would simply
> take too long.
>
> Perhaps, they would be willing to eat the time needed for that type of
> adjustment, but it doesn't seem likely. All they would need to do would be to
> add some monitoring circuits that they could access. I've seen that type of
> thing a lot. It would be cheaper to add a few circuits for a quick adjustment
> than it would be to spend the time on the adjustment. People's time is worth a
> lot more than a few components.
>
> On the other hand, tweaking the output voltage is something that is quickly
> measured as part of testing. Put it in a jig, make a quick check for
> functionality, tweak the output voltage and you are done. Or, perhaps it
> adjusts the duty cycle, the bias point or some other characteristic of the
> output signal. Perhaps it adjusts the reference voltage. I think I showed that
> it doesn't make a large change in the frequency. But, it doesn't make sense
> for it to make a small change (although I would be unable to measure a small
> change).
>
> I think that there are a lot of unexplored possibilities, but I definitely am
> not convinced that it sets either the inner or outer oven temperature. There
> are simply better ways to do that in production.
>
> I really, really want to know, though! I am going to try to repair mine one
> more time and see what I can measure. I didn't try very hard the first time,
> but I think its worth doing. If I can get it repaired again (I have to fix
> some traces, especially for the ground pin) it will probably take a couple of
> days. I have the parts to fix my fan circuit in my oscilloscope and I will do
> that first. And possibly tweak the power supply capacitors to reduce noise.
>
>
> Mike
>
>> If this is a double oven, there are two oven circuits and two oven 
>> controllers.
>> Both would have a set point and both would be adjusted somehow. The pot
>> may be the adjustment on the outer oven. Get things all set up and packaged,
>> then adjust the outer oven to make things do what the should do.
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

Anything electrical (duty cycle/ harmonics / output level / etc) 
is designed in on a modern part done in high volume. 

The only candidates for a pot on top of the oven are:

Inner oven temperature
Outer oven temperature
EFC

You have already ruled out EFC (it would be a coarse set so
visible on a normal counter). 

That leaves inner oven and outer oven. 

Why inner oven - to adjust for the data from your temperature run. The parts
are at best coarse set based on crystal temperature. 

Why outer oven - same as above or to set for inner / outer separation
and clearance after the thermal stabilization in the sealed can. 

If there is no apparent change in frequency (and from the location of
the pot) that suggests the outer oven. Regardless of which oven is being set, 
the
adjustment is likely a “move it 1.25 turns" sort of thing.  You then 
re-run the temperature test to see if it is in spec yet. 

Bob



> On Feb 20, 2016, at 2:56 PM, time...@metachaos.net wrote:
> 
> Bob,
> 
> I still have a problem with the various theories. Again, how is it measured?
> If you have a production line, you don't want a "tweak" that requires hours or
> days to determine.
> 
> As far as setting the crystal set point (presumably the inner over set point),
> that makes even less sense. Consider that they clearly knew the turn over
> point of the crystal BEFORE it was packaged. They wrote it on the sticker 
> inside.
> So, they would have no need to adjust the inner oven. That could easily have
> been done on the bench during assembly. It could also be done via a selection
> from a standardized set of components. That temperature is "sort of" critical.
> The curve is very flat, to it could be a little off. Since they knew the
> crystal turn over point in advance, there wouldn't be any need to "hunt" for
> it by an elaborate procedure after assembly.
> 
> However, the temperature of the outer oven is much less critical and I would
> suspect is simply set by the choice of components. And, if it needed tweaking
> then it could also have been done on the bench. Since they would know the
> thermal transfer characteristics, I suppose that they could measure the outer
> case's temperature to deduce the correct temperature of the outer oven. But,
> again, that doesn't make sense from a production standpoint. It would simply
> take too long.
> 
> Perhaps, they would be willing to eat the time needed for that type of
> adjustment, but it doesn't seem likely. All they would need to do would be to
> add some monitoring circuits that they could access. I've seen that type of
> thing a lot. It would be cheaper to add a few circuits for a quick adjustment
> than it would be to spend the time on the adjustment. People's time is worth a
> lot more than a few components.
> 
> On the other hand, tweaking the output voltage is something that is quickly
> measured as part of testing. Put it in a jig, make a quick check for
> functionality, tweak the output voltage and you are done. Or, perhaps it
> adjusts the duty cycle, the bias point or some other characteristic of the
> output signal. Perhaps it adjusts the reference voltage. I think I showed that
> it doesn't make a large change in the frequency. But, it doesn't make sense
> for it to make a small change (although I would be unable to measure a small
> change).
> 
> I think that there are a lot of unexplored possibilities, but I definitely am
> not convinced that it sets either the inner or outer oven temperature. There
> are simply better ways to do that in production.
> 
> I really, really want to know, though! I am going to try to repair mine one
> more time and see what I can measure. I didn't try very hard the first time,
> but I think its worth doing. If I can get it repaired again (I have to fix
> some traces, especially for the ground pin) it will probably take a couple of
> days. I have the parts to fix my fan circuit in my oscilloscope and I will do
> that first. And possibly tweak the power supply capacitors to reduce noise.
> 
> 
> Mike
> 
>> If this is a double oven, there are two oven circuits and two oven 
>> controllers.
>> Both would have a set point and both would be adjusted somehow. The pot
>> may be the adjustment on the outer oven. Get things all set up and packaged,
>> then adjust the outer oven to make things do what the should do.
> 
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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

Bob,

I still have a problem with the various theories. Again, how is it measured?
If you have a production line, you don't want a "tweak" that requires hours or
days to determine.

As far as setting the crystal set point (presumably the inner over set point),
that makes even less sense. Consider that they clearly knew the turn over
point of the crystal BEFORE it was packaged. They wrote it on the sticker 
inside.
So, they would have no need to adjust the inner oven. That could easily have
been done on the bench during assembly. It could also be done via a selection
from a standardized set of components. That temperature is "sort of" critical.
The curve is very flat, to it could be a little off. Since they knew the
crystal turn over point in advance, there wouldn't be any need to "hunt" for
it by an elaborate procedure after assembly.

However, the temperature of the outer oven is much less critical and I would
suspect is simply set by the choice of components. And, if it needed tweaking
then it could also have been done on the bench. Since they would know the
thermal transfer characteristics, I suppose that they could measure the outer
case's temperature to deduce the correct temperature of the outer oven. But,
again, that doesn't make sense from a production standpoint. It would simply
take too long.

Perhaps, they would be willing to eat the time needed for that type of
adjustment, but it doesn't seem likely. All they would need to do would be to
add some monitoring circuits that they could access. I've seen that type of
thing a lot. It would be cheaper to add a few circuits for a quick adjustment
than it would be to spend the time on the adjustment. People's time is worth a
lot more than a few components.

On the other hand, tweaking the output voltage is something that is quickly
measured as part of testing. Put it in a jig, make a quick check for
functionality, tweak the output voltage and you are done. Or, perhaps it
adjusts the duty cycle, the bias point or some other characteristic of the
output signal. Perhaps it adjusts the reference voltage. I think I showed that
it doesn't make a large change in the frequency. But, it doesn't make sense
for it to make a small change (although I would be unable to measure a small
change).

I think that there are a lot of unexplored possibilities, but I definitely am
not convinced that it sets either the inner or outer oven temperature. There
are simply better ways to do that in production.

I really, really want to know, though! I am going to try to repair mine one
more time and see what I can measure. I didn't try very hard the first time,
but I think its worth doing. If I can get it repaired again (I have to fix
some traces, especially for the ground pin) it will probably take a couple of
days. I have the parts to fix my fan circuit in my oscilloscope and I will do
that first. And possibly tweak the power supply capacitors to reduce noise.


Mike

> If this is a double oven, there are two oven circuits and two oven 
> controllers.
> Both would have a set point and both would be adjusted somehow. The pot
> may be the adjustment on the outer oven. Get things all set up and packaged,
> then adjust the outer oven to make things do what the should do.

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Re: [time-nuts] MTI 260-0624-D OCXO

[dan]

For anyone interested to know an induction heater, If you happen to 
have one laying around,
works pretty well for opening these types of cans up. Properly placed 
you can heat the can
melt the solder and not burn up any paper labels on the top of the can. 
If done carefully, they
can be reassembled this way also. 
 
My guess is even the cheap inductive cook tops would work for this. 
 

Dan
 
 
 

I have read sometime ago and probably on this list a success stories
about opening OCXOs using a hot air gun or even a propane torch, an
x-acto knife and a stainless steel shim sheet to avoid the solder to do
it stuff again when solidifying. 
Using this technique probably the can could be reused after repairing
the part. 


Ignacio EB4APL


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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

If this is a double oven, there are two oven circuits and two oven controllers. 
Both would have a set point and both would be adjusted somehow. The pot
may be the adjustment on the outer oven. Get things all set up and packaged,
then adjust the outer oven to make things do what the should do.

Bob

> On Feb 19, 2016, at 7:29 PM, EB4APL  wrote:
> 
> I have read sometime ago and probably on this list a success stories about 
> opening OCXOs using a hot air gun or even a propane torch, an x-acto knife  
> and a stainless steel shim sheet to avoid the solder to do it stuff again 
> when solidifying.
> Using this technique probably the can could be reused after repairing the 
> part.
> 
> Ignacio EB4APL
> 
> 
> 
> El 19/02/2016 a las 18:09, time...@metachaos.net wrote:
>> Alex,
>> 
>> I did not take opening pictures, but there is nothing to miss.
>> 
>> For the outside of the unopened case, there are plenty of pictures on eBay.
>> For the actual opening process, that consisted largely of scraping away 
>> solder
>> with a small, triangular file and utility knife until most of what I could
>> remove was gone and then using a hammer and screwdriver to separate the sides
>> from the bottom and then prying it off. Nothing pretty, and nothing much for
>> pictures. I used a tiny drill for my desoldering gun to remove an intial hole
>> in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
>> bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit 
>> will
>> fit through the hole, but it is very tight. Probably not best to drill with
>> it because that would most likely enlarge the hole.
>> 
>> I wouldn't open it the same way again, but I'm not sure of the best procedure
>> that leaves the case and contents undamaged so that it can be reassembled. I
>> think, perhaps, that I would remove all of the solder that I could as before.
>> But then, I would make some sort of cut-out for the pins on the bottom and 
>> put
>> it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
>> could be popped off. The outside case can get pretty hot without damage
>> because the only contact is the pins and the inside gets pretty hot when
>> running. The main risk is getting so hot that the plastic spacers on the pins
>> melt or the pin supports melt. I'm not sure how hot that would be. But, they
>> must have heated it fairly hot to melt the solder originally, so hopefully
>> that would work.
>> 
>> However, here are some pictures of the inside :) which is probably what you
>> want!
>> 
>> Top Case 1:[img]http://imgur.com/mvQkJ16[/img]
>> Top Case 2:[img]http://imgur.com/K7Rmeau[/img]
>> Bottom Case 1: [img]http://imgur.com/j7tC7QN[/img]
>> Bottom Case 2: [img]http://imgur.com/TKiofvi[/img]
>> Outer Oven 1:  [img]http://imgur.com/bzYywj7[/img]
>> Outer Oven 2:  [img]http://imgur.com/kKKynzc[/img]
>> Outer Oven 3:  [img]http://imgur.com/xtzFsXD[/img]
>> Circuit Board: [img]http://imgur.com/PHgnVIm[/img]
>> 
>> 
>> Mike
>> 
>> 
>>> Hi Mike,
>>> Would you be so kindly and post some pictures of the opening process of
>>> that OCSXO ?
>>> 73
>>> KJ6UHN
>>> Alex
>>> On 2/18/2016 7:54 PM, time...@metachaos.net wrote:
 Bob,
 
 The vendor has said that they did not want the unit back. So...
 
 I opened it up. Crudely, I admit. I learned a few things. I was concerned
 about the outer case heating up too much when I was trying to remove the
 solder. Turns out that the outer case doesn't touch anything except the 
 pins,
 so it can get pretty hot without any damage. Unfortunately, I used a bit of
 brute force to remove the casing after scraping away as much of the solder 
 as
 I could and after cracking the solder seal with a hammer and screw driver.
 Even using more heat, I'm not sure of the best way to remove the case. 
 Neither
 solder wick nor a vacuum desoldering tool is likely to remove all of the
 solder between the top case and the bottom.
 
 Even so, I got the case off. Somewhat bent, even bent the bottom circuit 
 board
 a bit. I discovered that there is a 2mm hole in the top that allows a 
 variable
 resistor to be adjusted. You need a pretty long, small screwdriver / 
 adjusting
 tool to do that, but that is probably for setting the center point. I would
 try to remove the solder rather than drilling, or drill upside down to 
 prevent
 solder flakes from falling inside.
 
 Also, I found that the -D on my part number appears to correspond to the 
 board
 revision, which is marked "Rev D". So the -C and -D parts probably have the
 same specifications. And, on the inside there is a marking "92.0" which I
 believe would be the set point for this specific crystal. So if I took the
 crystal out, I would know where to design the set point for a custom unit
 (currently beyond my skills, but who knows...).
 
 

Re: [time-nuts] MTI 260-0624-D OCXO

[Rex]

About opening cases, I opened one, repaired the oscillator and sealed it 
back up (sort of).


In the early 2000's I had a 10 MHz OCXO that I used as the main 
reference for my 10 GHz ham rover rig. It was really doing the job for 
me until I accidentally hooked it up to DC power backwards and killed 
it. I was hoping I could find some way to fix it. The oscillator was one 
of the larger metal packages about 3" long by about 2" square. Here's 
how I opened it.


Earlier I had tried to unsolder a smaller oscillator (about the size of 
the MTI 260) with a torch. It's hard to heat the two sections fast with 
a torch to melt the solder and find a way to grab them both ad pull 
apart while the solder is melted. On that attempt, I eventually got it 
apart but desoldered some internal circuit board components in the process.


For this other broken oscillator that I liked, I decided it might be 
better to mechanically cut it apart. I assumed that the bottom piece 
probably had a lip about 1/4 to 3/8 " long that fit tightly inside of 
the top case and that lip was soldered to join the two pieces. I wanted 
to cut off the top case right where the solder joint ended. I first 
drilled a small test hole into the side of the outer case about where I 
guessed the solder joint ended inside, Ideally just through the outer 
case. Then with a small Dremel bit I enlarged this hole to to figure out 
exactly where the solder seam ended. Then I carefully cut the main case 
around the end of the solder joint. Ideally I cut just a little below 
the end of the inner lip to keep a slight aligning surface for putting 
it back together later.


For the cutting, I had a milling machine that I used, But once you know 
where you want to cut, I think careful hack sawing or a Dremel ceramic 
disk could have done the job. With only a little bit of solder now 
holding the cut top case on, a little prying removed it.


[Another option might be to cut vertical slits in the outer case just 
either side of the round corners (8 cuts) and just as long as the 
internal soldered flange. The object is to turn the bottom sides of the 
outer case into tabs that can be bent out. Driving a knife or chisel 
into the solderd seam will hopefully pry the flaps outward. Getting the 
corners loose would probably be the hard part. Cutting them as in my 
other method might be the easiest. With this method, after opening, I 
think you could then cut or melt of excess solder.off the main case and 
base, straighten the main case sides and get a good strong seam on 
reassembly.]


The blown oscillator I cut open had smt components inside. I replaced 
all the active devices and electrolytic caps I found in the circuit and 
checked to find that it worked again. (Yay!) I then was able to solder 
the top case back on the base. Not quite as strong as the original with 
just a narrow solder bead holding it, but working good as new.


Of course, if the oscillator's metal case is providing a hermetic seal, 
you loose that, but most aren't, anyway.


So I just thought I'd mention this other mechanical attack method. I 
think unsoldering the whole solder seal in one go and pulling it apart 
without damaging the internals is a pretty difficult task.


-Rex


On 2/19/2016 9:09 AM, time...@metachaos.net wrote:

Alex,

I did not take opening pictures, but there is nothing to miss.

For the outside of the unopened case, there are plenty of pictures on eBay.
For the actual opening process, that consisted largely of scraping away solder
with a small, triangular file and utility knife until most of what I could
remove was gone and then using a hammer and screwdriver to separate the sides
from the bottom and then prying it off. Nothing pretty, and nothing much for
pictures. I used a tiny drill for my desoldering gun to remove an intial hole
in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit will
fit through the hole, but it is very tight. Probably not best to drill with
it because that would most likely enlarge the hole.

I wouldn't open it the same way again, but I'm not sure of the best procedure
that leaves the case and contents undamaged so that it can be reassembled. I
think, perhaps, that I would remove all of the solder that I could as before.
But then, I would make some sort of cut-out for the pins on the bottom and put
it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
could be popped off. The outside case can get pretty hot without damage
because the only contact is the pins and the inside gets pretty hot when
running. The main risk is getting so hot that the plastic spacers on the pins
melt or the pin supports melt. I'm not sure how hot that would be. But, they
must have heated it fairly hot to melt the solder originally, so hopefully
that would work.

However, here are some pictures of the inside :) which is probably what you
want!

Top Case 1:   

Re: [time-nuts] MTI 260-0624-D OCXO

[Don@True-Cal]

It always helps to know a little about the specific design of the temp control 
circuit but let's say counter clockwise CCW reduces the internal oven temp. 
This can be confirmed by letting the temp and frequency stabilize. Using a 
counter with good resolution monitoring the output frequency, turn the pot CCW 
several turns and the frequency should slowly decrease a few cycles (typically 
positive temp coefficient) as the oven cools. Now slowly turn the pot CW about 
1/2 turn on each increment watching the frequency slowly increase due to the 
internal crystal oven slowly getting hotter. Eventually, the frequency will 
peak and further CW turning of the pot will start to lower the frequency. 
That's why it called the turn-over temperature. Now set the pot in the middle 
of two equal frequency points on either side of the frequency peak. Hopefully 
you will see a broad frequency peak allowing for a little more margin in the 
oven temperature. All you need to monitor is the output frequency. This
  process can be a little faster if you have some type of external analog oven 
temperature indication but it not necessary.

Don

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of 
time...@metachaos.net
Sent: Friday, February 19, 2016 9:02 PM
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Subject: Re: [time-nuts] MTI 260-0624-D OCXO

I have just about finished trashing this OCXO. I was able to run it outside of 
its case, and I have repaired the case, but I was unable to reinstall it into 
the case because I have to patch it on both the top and bottom. I could, 
perhaps, put it into a larger case and might do that later. For now, I will 
keep it as a potential future resource. The SC crystal is worth that much - 
they aren't cheap and nothing wrong with that. Also, just the bottom circuit 
board has problems, possibly another bad unit could be used for parts.

That leaves one final question. The suggestion that the POT adjusts the 
temperature set point for the crystal sounds very reasonable. It clearly does 
not significantly affect the frequency. At least, not in the range that would 
allow for tuning the output frequency.

However, the POT is clearly designed to be adjusted AFTER everything is 
assembled because it is intended to be adjusted through the hole in the case.
That assumes some sort of feedback. What feedback? What can it affect on the 
available five pins that would let you know when the temperature is set 
correctly? If it is not for setting the temperature, and not for setting the 
frequency, what is it for? Perhaps output voltage level? I would have to get it 
working again, but I could test that. Any ideas?


Mike

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Re: [time-nuts] MTI 260-0624-D OCXO

[Hal Murray]

time...@metachaos.net said:
> However, the POT is clearly designed to be adjusted AFTER everything is
> assembled because it is intended to be adjusted through the hole in the
> case. That assumes some sort of feedback. What feedback?

If it adjusts the temperature, the idea is to tune it so that it runs at a 
flat spot on the temperature vs frequency curve.  You don't actually care 
what the temperature is, just that you set it at the flat spot.  You could 
measure the curve with several data points, then interpolate and set it to 
the best spot.

I'd expect something like that is part of the burn in process.  I wonder if 
they have it automated or if a human has to make each adjustment.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] MTI 260-0624-D OCXO

[wb6bnq]

Hi Mike,

There are three possibilities in play.

1. The pot does set the EFC range OR
2. It adjusts the oven temperature.
3. In either case the adjustment range may be small enough that your 
current equipment resolution may not be able to see the change.


If it were the EFC adjustment, I would think that should be see able.  
The oven set point circuitry may mask the pot change in that the pot's 
range may be just a small fraction of the total temperature adjustment.  
That is to say there may be fixed resistors in series with the pot that 
would have a bigger effect.  The fixed values set it to near the 
turnover point and the pot's small value may have just enough range to 
make it just past the turnover point.


My two cents,

BillWB6BNQ


time...@metachaos.net wrote:


I have just about finished trashing this OCXO. I was able to run it outside of
its case, and I have repaired the case, but I was unable to reinstall it into
the case because I have to patch it on both the top and bottom. I could,
perhaps, put it into a larger case and might do that later. For now, I will
keep it as a potential future resource. The SC crystal is worth that much -
they aren't cheap and nothing wrong with that. Also, just the bottom circuit
board has problems, possibly another bad unit could be used for parts.

That leaves one final question. The suggestion that the POT adjusts the
temperature set point for the crystal sounds very reasonable. It clearly does
not significantly affect the frequency. At least, not in the range that would
allow for tuning the output frequency.

However, the POT is clearly designed to be adjusted AFTER everything is
assembled because it is intended to be adjusted through the hole in the case.
That assumes some sort of feedback. What feedback? What can it affect on the
available five pins that would let you know when the temperature is set
correctly? If it is not for setting the temperature, and not for setting the
frequency, what is it for? Perhaps output voltage level? I would have to get
it working again, but I could test that. Any ideas?


Mike

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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

I have just about finished trashing this OCXO. I was able to run it outside of
its case, and I have repaired the case, but I was unable to reinstall it into
the case because I have to patch it on both the top and bottom. I could,
perhaps, put it into a larger case and might do that later. For now, I will
keep it as a potential future resource. The SC crystal is worth that much -
they aren't cheap and nothing wrong with that. Also, just the bottom circuit
board has problems, possibly another bad unit could be used for parts.

That leaves one final question. The suggestion that the POT adjusts the
temperature set point for the crystal sounds very reasonable. It clearly does
not significantly affect the frequency. At least, not in the range that would
allow for tuning the output frequency.

However, the POT is clearly designed to be adjusted AFTER everything is
assembled because it is intended to be adjusted through the hole in the case.
That assumes some sort of feedback. What feedback? What can it affect on the
available five pins that would let you know when the temperature is set
correctly? If it is not for setting the temperature, and not for setting the
frequency, what is it for? Perhaps output voltage level? I would have to get
it working again, but I could test that. Any ideas?


Mike

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Re: [time-nuts] MTI 260-0624-D OCXO

[EB4APL]

I have read sometime ago and probably on this list a success stories 
about opening OCXOs using a hot air gun or even a propane torch, an 
x-acto knife  and a stainless steel shim sheet to avoid the solder to do 
it stuff again when solidifying.
Using this technique probably the can could be reused after repairing 
the part.


Ignacio EB4APL



El 19/02/2016 a las 18:09, time...@metachaos.net wrote:

Alex,

I did not take opening pictures, but there is nothing to miss.

For the outside of the unopened case, there are plenty of pictures on eBay.
For the actual opening process, that consisted largely of scraping away solder
with a small, triangular file and utility knife until most of what I could
remove was gone and then using a hammer and screwdriver to separate the sides
from the bottom and then prying it off. Nothing pretty, and nothing much for
pictures. I used a tiny drill for my desoldering gun to remove an intial hole
in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit will
fit through the hole, but it is very tight. Probably not best to drill with
it because that would most likely enlarge the hole.

I wouldn't open it the same way again, but I'm not sure of the best procedure
that leaves the case and contents undamaged so that it can be reassembled. I
think, perhaps, that I would remove all of the solder that I could as before.
But then, I would make some sort of cut-out for the pins on the bottom and put
it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
could be popped off. The outside case can get pretty hot without damage
because the only contact is the pins and the inside gets pretty hot when
running. The main risk is getting so hot that the plastic spacers on the pins
melt or the pin supports melt. I'm not sure how hot that would be. But, they
must have heated it fairly hot to melt the solder originally, so hopefully
that would work.

However, here are some pictures of the inside :) which is probably what you
want!

Top Case 1:[img]http://imgur.com/mvQkJ16[/img]
Top Case 2:[img]http://imgur.com/K7Rmeau[/img]
Bottom Case 1: [img]http://imgur.com/j7tC7QN[/img]
Bottom Case 2: [img]http://imgur.com/TKiofvi[/img]
Outer Oven 1:  [img]http://imgur.com/bzYywj7[/img]
Outer Oven 2:  [img]http://imgur.com/kKKynzc[/img]
Outer Oven 3:  [img]http://imgur.com/xtzFsXD[/img]
Circuit Board: [img]http://imgur.com/PHgnVIm[/img]


Mike



Hi Mike,
Would you be so kindly and post some pictures of the opening process of
that OCSXO ?
73
KJ6UHN
Alex
On 2/18/2016 7:54 PM, time...@metachaos.net wrote:

Bob,

The vendor has said that they did not want the unit back. So...

I opened it up. Crudely, I admit. I learned a few things. I was concerned
about the outer case heating up too much when I was trying to remove the
solder. Turns out that the outer case doesn't touch anything except the pins,
so it can get pretty hot without any damage. Unfortunately, I used a bit of
brute force to remove the casing after scraping away as much of the solder as
I could and after cracking the solder seal with a hammer and screw driver.
Even using more heat, I'm not sure of the best way to remove the case. Neither
solder wick nor a vacuum desoldering tool is likely to remove all of the
solder between the top case and the bottom.

Even so, I got the case off. Somewhat bent, even bent the bottom circuit board
a bit. I discovered that there is a 2mm hole in the top that allows a variable
resistor to be adjusted. You need a pretty long, small screwdriver / adjusting
tool to do that, but that is probably for setting the center point. I would
try to remove the solder rather than drilling, or drill upside down to prevent
solder flakes from falling inside.

Also, I found that the -D on my part number appears to correspond to the board
revision, which is marked "Rev D". So the -C and -D parts probably have the
same specifications. And, on the inside there is a marking "92.0" which I
believe would be the set point for this specific crystal. So if I took the
crystal out, I would know where to design the set point for a custom unit
(currently beyond my skills, but who knows...).

  From there, I removed the bottom casing. That caused additional damage, some
lifted traces and even one very small part (tiny, SMD, who knows?).

But, I then soldered wires directly to the board, making patches for the
lifted traces.

I plugged it in.

I turned it on.

Success!

I gave it 12v which should supply 2A, but it dropped the voltage down to just
over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
nothing attached to the adjustment pin. After some time, the frequency
stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached
the adjustment pin to ground, there was no change. When I attached the
adjustment pin to 

Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

The neatest thing I’ve seen to open an OCXO is a big old gizmo made by 
Lepell(??). Roughly a 3’ high rack enclosure. Inside you had a ~ 1KW MOPA
transmitter at “sort of 13 MHz”. You tuned the thing into a copper tube wrapped 
around
the OCXO base. The net result was that the RF all went into losses in the steel 
can / base. The whole thing heated up in no time at all. No idea where it came 
from
or how old it was. 

In some cases the only real way to get one open is to “peel” the can off the 
base.
Get a *good* set of gloves if you try to do this. The can is trash, but in  
theory, the 
base and the guts are in fine shape. Not quite clear what you do for a new can 
if
you want to put it back together. 

Bob


> On Feb 19, 2016, at 12:09 PM, time...@metachaos.net wrote:
> 
> Alex,
> 
> I did not take opening pictures, but there is nothing to miss.
> 
> For the outside of the unopened case, there are plenty of pictures on eBay.
> For the actual opening process, that consisted largely of scraping away solder
> with a small, triangular file and utility knife until most of what I could
> remove was gone and then using a hammer and screwdriver to separate the sides
> from the bottom and then prying it off. Nothing pretty, and nothing much for
> pictures. I used a tiny drill for my desoldering gun to remove an intial hole
> in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
> bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit will
> fit through the hole, but it is very tight. Probably not best to drill with
> it because that would most likely enlarge the hole.
> 
> I wouldn't open it the same way again, but I'm not sure of the best procedure
> that leaves the case and contents undamaged so that it can be reassembled. I
> think, perhaps, that I would remove all of the solder that I could as before.
> But then, I would make some sort of cut-out for the pins on the bottom and put
> it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
> could be popped off. The outside case can get pretty hot without damage
> because the only contact is the pins and the inside gets pretty hot when
> running. The main risk is getting so hot that the plastic spacers on the pins
> melt or the pin supports melt. I'm not sure how hot that would be. But, they
> must have heated it fairly hot to melt the solder originally, so hopefully
> that would work.
> 
> However, here are some pictures of the inside :) which is probably what you
> want!
> 
> Top Case 1:[img]http://imgur.com/mvQkJ16[/img]
> Top Case 2:[img]http://imgur.com/K7Rmeau[/img]
> Bottom Case 1: [img]http://imgur.com/j7tC7QN[/img]
> Bottom Case 2: [img]http://imgur.com/TKiofvi[/img]
> Outer Oven 1:  [img]http://imgur.com/bzYywj7[/img]
> Outer Oven 2:  [img]http://imgur.com/kKKynzc[/img]
> Outer Oven 3:  [img]http://imgur.com/xtzFsXD[/img]
> Circuit Board: [img]http://imgur.com/PHgnVIm[/img]
> 
> 
> Mike
> 
> 
>> Hi Mike,
>> Would you be so kindly and post some pictures of the opening process of 
>> that OCSXO ?
>> 73
>> KJ6UHN
>> Alex
>> On 2/18/2016 7:54 PM, time...@metachaos.net wrote:
>>> Bob,
>>> 
>>> The vendor has said that they did not want the unit back. So...
>>> 
>>> I opened it up. Crudely, I admit. I learned a few things. I was concerned
>>> about the outer case heating up too much when I was trying to remove the
>>> solder. Turns out that the outer case doesn't touch anything except the 
>>> pins,
>>> so it can get pretty hot without any damage. Unfortunately, I used a bit of
>>> brute force to remove the casing after scraping away as much of the solder 
>>> as
>>> I could and after cracking the solder seal with a hammer and screw driver.
>>> Even using more heat, I'm not sure of the best way to remove the case. 
>>> Neither
>>> solder wick nor a vacuum desoldering tool is likely to remove all of the
>>> solder between the top case and the bottom.
>>> 
>>> Even so, I got the case off. Somewhat bent, even bent the bottom circuit 
>>> board
>>> a bit. I discovered that there is a 2mm hole in the top that allows a 
>>> variable
>>> resistor to be adjusted. You need a pretty long, small screwdriver / 
>>> adjusting
>>> tool to do that, but that is probably for setting the center point. I would
>>> try to remove the solder rather than drilling, or drill upside down to 
>>> prevent
>>> solder flakes from falling inside.
>>> 
>>> Also, I found that the -D on my part number appears to correspond to the 
>>> board
>>> revision, which is marked "Rev D". So the -C and -D parts probably have the
>>> same specifications. And, on the inside there is a marking "92.0" which I
>>> believe would be the set point for this specific crystal. So if I took the
>>> crystal out, I would know where to design the set point for a custom unit
>>> (currently beyond my skills, but who knows...).
>>> 
>>> From there, I removed the bottom casing. That caused additional damage, some
>>> lifted traces and even one 

Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

Alex,

I did not take opening pictures, but there is nothing to miss.

For the outside of the unopened case, there are plenty of pictures on eBay.
For the actual opening process, that consisted largely of scraping away solder
with a small, triangular file and utility knife until most of what I could
remove was gone and then using a hammer and screwdriver to separate the sides
from the bottom and then prying it off. Nothing pretty, and nothing much for
pictures. I used a tiny drill for my desoldering gun to remove an intial hole
in the solder for the adjustment hole. I then enlarged it with a 1/16th drill
bit (by hand). Ideally, a 2mm drill bit could be used. A 5/64th drill bit will
fit through the hole, but it is very tight. Probably not best to drill with
it because that would most likely enlarge the hole.

I wouldn't open it the same way again, but I'm not sure of the best procedure
that leaves the case and contents undamaged so that it can be reassembled. I
think, perhaps, that I would remove all of the solder that I could as before.
But then, I would make some sort of cut-out for the pins on the bottom and put
it in a pan on the stove and heat it up (hopefully, evenly) until the bottom
could be popped off. The outside case can get pretty hot without damage
because the only contact is the pins and the inside gets pretty hot when
running. The main risk is getting so hot that the plastic spacers on the pins
melt or the pin supports melt. I'm not sure how hot that would be. But, they
must have heated it fairly hot to melt the solder originally, so hopefully
that would work.

However, here are some pictures of the inside :) which is probably what you
want!

Top Case 1:[img]http://imgur.com/mvQkJ16[/img]
Top Case 2:[img]http://imgur.com/K7Rmeau[/img]
Bottom Case 1: [img]http://imgur.com/j7tC7QN[/img]
Bottom Case 2: [img]http://imgur.com/TKiofvi[/img]
Outer Oven 1:  [img]http://imgur.com/bzYywj7[/img]
Outer Oven 2:  [img]http://imgur.com/kKKynzc[/img]
Outer Oven 3:  [img]http://imgur.com/xtzFsXD[/img]
Circuit Board: [img]http://imgur.com/PHgnVIm[/img]


Mike


> Hi Mike,
> Would you be so kindly and post some pictures of the opening process of 
> that OCSXO ?
> 73
> KJ6UHN
> Alex
> On 2/18/2016 7:54 PM, time...@metachaos.net wrote:
>> Bob,
>>
>> The vendor has said that they did not want the unit back. So...
>>
>> I opened it up. Crudely, I admit. I learned a few things. I was concerned
>> about the outer case heating up too much when I was trying to remove the
>> solder. Turns out that the outer case doesn't touch anything except the pins,
>> so it can get pretty hot without any damage. Unfortunately, I used a bit of
>> brute force to remove the casing after scraping away as much of the solder as
>> I could and after cracking the solder seal with a hammer and screw driver.
>> Even using more heat, I'm not sure of the best way to remove the case. 
>> Neither
>> solder wick nor a vacuum desoldering tool is likely to remove all of the
>> solder between the top case and the bottom.
>>
>> Even so, I got the case off. Somewhat bent, even bent the bottom circuit 
>> board
>> a bit. I discovered that there is a 2mm hole in the top that allows a 
>> variable
>> resistor to be adjusted. You need a pretty long, small screwdriver / 
>> adjusting
>> tool to do that, but that is probably for setting the center point. I would
>> try to remove the solder rather than drilling, or drill upside down to 
>> prevent
>> solder flakes from falling inside.
>>
>> Also, I found that the -D on my part number appears to correspond to the 
>> board
>> revision, which is marked "Rev D". So the -C and -D parts probably have the
>> same specifications. And, on the inside there is a marking "92.0" which I
>> believe would be the set point for this specific crystal. So if I took the
>> crystal out, I would know where to design the set point for a custom unit
>> (currently beyond my skills, but who knows...).
>>
>>  From there, I removed the bottom casing. That caused additional damage, some
>> lifted traces and even one very small part (tiny, SMD, who knows?).
>>
>> But, I then soldered wires directly to the board, making patches for the
>> lifted traces.
>>
>> I plugged it in.
>>
>> I turned it on.
>>
>> Success!
>>
>> I gave it 12v which should supply 2A, but it dropped the voltage down to just
>> over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
>> to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
>> nothing attached to the adjustment pin. After some time, the frequency
>> stabilized at 5.14Mhz and the voltage came back up to 10v. When I 
>> attached
>> the adjustment pin to ground, there was no change. When I attached the
>> adjustment pin to Vref (which is at 6.15v), the frequency dropped to
>> 5.10Mhz. So apparently, these units adjust negatively. But also have a
>> very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment
>> range is 0..6v. I 

Re: [time-nuts] MTI 260-0624-D OCXO

[Alex Pummer]

Hi Mike,
Would you be so kindly and post some pictures of the opening process of 
that OCSXO ?

73
KJ6UHN
Alex
On 2/18/2016 7:54 PM, time...@metachaos.net wrote:

Bob,

The vendor has said that they did not want the unit back. So...

I opened it up. Crudely, I admit. I learned a few things. I was concerned
about the outer case heating up too much when I was trying to remove the
solder. Turns out that the outer case doesn't touch anything except the pins,
so it can get pretty hot without any damage. Unfortunately, I used a bit of
brute force to remove the casing after scraping away as much of the solder as
I could and after cracking the solder seal with a hammer and screw driver.
Even using more heat, I'm not sure of the best way to remove the case. Neither
solder wick nor a vacuum desoldering tool is likely to remove all of the
solder between the top case and the bottom.

Even so, I got the case off. Somewhat bent, even bent the bottom circuit board
a bit. I discovered that there is a 2mm hole in the top that allows a variable
resistor to be adjusted. You need a pretty long, small screwdriver / adjusting
tool to do that, but that is probably for setting the center point. I would
try to remove the solder rather than drilling, or drill upside down to prevent
solder flakes from falling inside.

Also, I found that the -D on my part number appears to correspond to the board
revision, which is marked "Rev D". So the -C and -D parts probably have the
same specifications. And, on the inside there is a marking "92.0" which I
believe would be the set point for this specific crystal. So if I took the
crystal out, I would know where to design the set point for a custom unit
(currently beyond my skills, but who knows...).

 From there, I removed the bottom casing. That caused additional damage, some
lifted traces and even one very small part (tiny, SMD, who knows?).

But, I then soldered wires directly to the board, making patches for the
lifted traces.

I plugged it in.

I turned it on.

Success!

I gave it 12v which should supply 2A, but it dropped the voltage down to just
over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
nothing attached to the adjustment pin. After some time, the frequency
stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached
the adjustment pin to ground, there was no change. When I attached the
adjustment pin to Vref (which is at 6.15v), the frequency dropped to
5.10Mhz. So apparently, these units adjust negatively. But also have a
very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment
range is 0..6v. I attached the adjustment pin to +10v and the frequency
dropped another 3Hz for a 1.4e-6 adjustment range.

I don't expect that this specific unit will be very useful given the damage
that I caused opening it up. But, probably there were just bad connections
internally, so if I were much more careful in the disassembly, I could
probably have fixed it. Something to keep in mind for the next unit.

I may be wrong for what the variable resistor does. Turning it made no
difference in the frequency.

I also suspect, but don't know that the difference from 5Mhz is due to the
frequency counter being uncalibrated. It could also because I damaged the unit
or just because it is very far off from where it should be.

Still, I learned a lot, and well worth the time spent.


Mike



Hi
The one advantage you have in testing a used OCXO is you have a pretty good 
idea of how
you are going to use it. If phase noise does not matter to you … no need to 
test. I’d always check
that it tunes on freq with reasonable EFC range left over. I’d also make sure 
that it warms up
properly (oven works) and that it has a reasonable output. What goes on the 
list past that …
it depends on what you need.
The gear you have will check aging and get it set on frequency fine. It will 
check it for “wander”
as your lab heats up and cools down. With a GPSDO and a simple phase lock, a 
DVM may be
all you really need to do most of that. You will not have a proper ADEV, but 
you will know it works
pretty well (or not ..).
A lightbulb oven / bench / fridge /freezer proces can give you a wide range TC 
if you need it.
If you do get into phase noise, a sound card system will get you going. For 
ADEV, the 10811’s
tune far enough that a single mixer system with your 53131 will give you good 
data. Both
of those will involve some building, but not a lot of money.
There is one thing about the 10811’s: They are not sealed units. They tend to 
soak up humidity
when stored in most parts of the country. You may want to run them for a month 
or three
before doing any fancy testing.
Bob

On Feb 18, 2016, at 7:40 AM, Adrian Godwin  wrote:

I have a small collection of 10811 and similar oscillators here, collected
from hamfests rather than china (and mostly pre-ebay).

What sort of 

Re: [time-nuts] MTI 260-0624-D OCXO

[wb6bnq]

Mike,

Way more likely that "POT" set the temperature of the oven.

BillWB6BNQ


time...@metachaos.net wrote:


Bob,

The vendor has said that they did not want the unit back. So...

I opened it up. Crudely, I admit. I learned a few things. I was concerned
about the outer case heating up too much when I was trying to remove the
solder. Turns out that the outer case doesn't touch anything except the pins,
so it can get pretty hot without any damage. Unfortunately, I used a bit of
brute force to remove the casing after scraping away as much of the solder as
I could and after cracking the solder seal with a hammer and screw driver.
Even using more heat, I'm not sure of the best way to remove the case. Neither
solder wick nor a vacuum desoldering tool is likely to remove all of the
solder between the top case and the bottom.

Even so, I got the case off. Somewhat bent, even bent the bottom circuit board
a bit. I discovered that there is a 2mm hole in the top that allows a variable
resistor to be adjusted. You need a pretty long, small screwdriver / adjusting
tool to do that, but that is probably for setting the center point. I would
try to remove the solder rather than drilling, or drill upside down to prevent
solder flakes from falling inside.

Also, I found that the -D on my part number appears to correspond to the board
revision, which is marked "Rev D". So the -C and -D parts probably have the
same specifications. And, on the inside there is a marking "92.0" which I
believe would be the set point for this specific crystal. So if I took the
crystal out, I would know where to design the set point for a custom unit
(currently beyond my skills, but who knows...).


From there, I removed the bottom casing. That caused additional damage, some

lifted traces and even one very small part (tiny, SMD, who knows?).

But, I then soldered wires directly to the board, making patches for the
lifted traces.

I plugged it in.

I turned it on.

Success!

I gave it 12v which should supply 2A, but it dropped the voltage down to just
over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
nothing attached to the adjustment pin. After some time, the frequency
stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached
the adjustment pin to ground, there was no change. When I attached the
adjustment pin to Vref (which is at 6.15v), the frequency dropped to
5.10Mhz. So apparently, these units adjust negatively. But also have a
very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment
range is 0..6v. I attached the adjustment pin to +10v and the frequency
dropped another 3Hz for a 1.4e-6 adjustment range.

I don't expect that this specific unit will be very useful given the damage
that I caused opening it up. But, probably there were just bad connections
internally, so if I were much more careful in the disassembly, I could
probably have fixed it. Something to keep in mind for the next unit.

I may be wrong for what the variable resistor does. Turning it made no
difference in the frequency.

I also suspect, but don't know that the difference from 5Mhz is due to the
frequency counter being uncalibrated. It could also because I damaged the unit
or just because it is very far off from where it should be.

Still, I learned a lot, and well worth the time spent.


Mike


 


Hi
   



 


The one advantage you have in testing a used OCXO is you have a pretty good 
idea of how
you are going to use it. If phase noise does not matter to you … no need to 
test. I’d always check
that it tunes on freq with reasonable EFC range left over. I’d also make sure 
that it warms up
properly (oven works) and that it has a reasonable output. What goes on the 
list past that …
it depends on what you need. 
   



 


The gear you have will check aging and get it set on frequency fine. It will 
check it for “wander”
as your lab heats up and cools down. With a GPSDO and a simple phase lock, a 
DVM may be
all you really need to do most of that. You will not have a proper ADEV, but 
you will know it works
pretty well (or not ..).
   



 


A lightbulb oven / bench / fridge /freezer proces can give you a wide range TC 
if you need it.
   



 


If you do get into phase noise, a sound card system will get you going. For 
ADEV, the 10811’s
tune far enough that a single mixer system with your 53131 will give you good 
data. Both
of those will involve some building, but not a lot of money.
   



 


There is one thing about the 10811’s: They are not sealed units. They tend to 
soak up humidity
when stored in most parts of the country. You may want to run them for a month 
or three
before doing any fancy testing.
   



 

Bob 
   



 


On Feb 18, 2016, at 7:40 AM, Adrian Godwin  wrote:

I have a small collection of 10811 and similar oscillators here, collected
from hamfests rather than china 

Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

Bob,

The vendor has said that they did not want the unit back. So...

I opened it up. Crudely, I admit. I learned a few things. I was concerned
about the outer case heating up too much when I was trying to remove the
solder. Turns out that the outer case doesn't touch anything except the pins,
so it can get pretty hot without any damage. Unfortunately, I used a bit of
brute force to remove the casing after scraping away as much of the solder as
I could and after cracking the solder seal with a hammer and screw driver.
Even using more heat, I'm not sure of the best way to remove the case. Neither
solder wick nor a vacuum desoldering tool is likely to remove all of the
solder between the top case and the bottom.

Even so, I got the case off. Somewhat bent, even bent the bottom circuit board
a bit. I discovered that there is a 2mm hole in the top that allows a variable
resistor to be adjusted. You need a pretty long, small screwdriver / adjusting
tool to do that, but that is probably for setting the center point. I would
try to remove the solder rather than drilling, or drill upside down to prevent
solder flakes from falling inside.

Also, I found that the -D on my part number appears to correspond to the board
revision, which is marked "Rev D". So the -C and -D parts probably have the
same specifications. And, on the inside there is a marking "92.0" which I
believe would be the set point for this specific crystal. So if I took the
crystal out, I would know where to design the set point for a custom unit
(currently beyond my skills, but who knows...).

>From there, I removed the bottom casing. That caused additional damage, some
lifted traces and even one very small part (tiny, SMD, who knows?).

But, I then soldered wires directly to the board, making patches for the
lifted traces.

I plugged it in.

I turned it on.

Success!

I gave it 12v which should supply 2A, but it dropped the voltage down to just
over 9V. Even so, I got a nice sine wave out at around 4.999790Mhz according
to my (uncalibrated) scope and around 800mV (into 50 ohm, DC). That was with
nothing attached to the adjustment pin. After some time, the frequency
stabilized at 5.14Mhz and the voltage came back up to 10v. When I attached
the adjustment pin to ground, there was no change. When I attached the
adjustment pin to Vref (which is at 6.15v), the frequency dropped to
5.10Mhz. So apparently, these units adjust negatively. But also have a
very wide adjustment range of 4Hz (8e-7). I am assuming that the adjustment
range is 0..6v. I attached the adjustment pin to +10v and the frequency
dropped another 3Hz for a 1.4e-6 adjustment range.

I don't expect that this specific unit will be very useful given the damage
that I caused opening it up. But, probably there were just bad connections
internally, so if I were much more careful in the disassembly, I could
probably have fixed it. Something to keep in mind for the next unit.

I may be wrong for what the variable resistor does. Turning it made no
difference in the frequency.

I also suspect, but don't know that the difference from 5Mhz is due to the
frequency counter being uncalibrated. It could also because I damaged the unit
or just because it is very far off from where it should be.

Still, I learned a lot, and well worth the time spent.


Mike


> Hi

> The one advantage you have in testing a used OCXO is you have a pretty good 
> idea of how
> you are going to use it. If phase noise does not matter to you … no need to 
> test. I’d always check
> that it tunes on freq with reasonable EFC range left over. I’d also make sure 
> that it warms up
> properly (oven works) and that it has a reasonable output. What goes on the 
> list past that …
> it depends on what you need. 

> The gear you have will check aging and get it set on frequency fine. It will 
> check it for “wander”
> as your lab heats up and cools down. With a GPSDO and a simple phase lock, a 
> DVM may be
> all you really need to do most of that. You will not have a proper ADEV, but 
> you will know it works
> pretty well (or not ..).

> A lightbulb oven / bench / fridge /freezer proces can give you a wide range 
> TC if you need it.

> If you do get into phase noise, a sound card system will get you going. For 
> ADEV, the 10811’s
> tune far enough that a single mixer system with your 53131 will give you good 
> data. Both
> of those will involve some building, but not a lot of money.

> There is one thing about the 10811’s: They are not sealed units. They tend to 
> soak up humidity
> when stored in most parts of the country. You may want to run them for a 
> month or three
> before doing any fancy testing.

> Bob 

>> On Feb 18, 2016, at 7:40 AM, Adrian Godwin  wrote:
>> 
>> I have a small collection of 10811 and similar oscillators here, collected
>> from hamfests rather than china (and mostly pre-ebay).
>> 
>> What sort of testing regime would you put them through ? I don't have
>> anything as exotic 

Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

The one advantage you have in testing a used OCXO is you have a pretty good 
idea of how
you are going to use it. If phase noise does not matter to you … no need to 
test. I’d always check
that it tunes on freq with reasonable EFC range left over. I’d also make sure 
that it warms up 
properly (oven works) and that it has a reasonable output. What goes on the 
list past that …
it depends on what you need. 

The gear you have will check aging and get it set on frequency fine. It will 
check it for “wander” 
as your lab heats up and cools down. With a GPSDO and a simple phase lock, a 
DVM may be
all you really need to do most of that. You will not have a proper ADEV, but 
you will know it works
pretty well (or not ..).

A lightbulb oven / bench / fridge /freezer proces can give you a wide range TC 
if you need it. 

If you do get into phase noise, a sound card system will get you going. For 
ADEV, the 10811’s 
tune far enough that a single mixer system with your 53131 will give you good 
data. Both 
of those will involve some building, but not a lot of money.

There is one thing about the 10811’s: They are not sealed units. They tend to 
soak up humidity
when stored in most parts of the country. You may want to run them for a month 
or three 
before doing any fancy testing.

Bob 

> On Feb 18, 2016, at 7:40 AM, Adrian Godwin  wrote:
> 
> I have a small collection of 10811 and similar oscillators here, collected
> from hamfests rather than china (and mostly pre-ebay).
> 
> What sort of testing regime would you put them through ? I don't have
> anything as exotic as a timepod but I do have an HP53131A, the Tait Rb
> source, and a KS-24361 set up. And always keen to get hints on the
> acquisition of new toys !
> 
> 
> 
> On Thu, Feb 18, 2016 at 12:09 PM, Bob Camp  wrote:
> 
>> Hi
>> 
>> It is *much* better to have an OCXO that you do not need to test to death.
>> There is simply to much testing to do. A modern factory does not test the
>> quality into the product (of any sort) they design in and build it in. The
>> same
>> is true of the normal customer for virtually any component. They make sure
>> the parts come from somebody they can trust and save a lot of testing time.
>> 
>> That said, yes, I have a pile of scrap parts sitting in front of me as I
>> type this.
>> It’s a hobby. Time does not count. It lets me play with all sorts of toys
>> doing
>> the testing. I occasionally learn things in the process. Mostly I learn
>> that
>> my hope of a 100% perfect batch is still a dream ….
>> 
>> Bob
>> 
>> 
>> 
>>> On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote:
>>> 
>>> Bob,
>>> 
>>> In this case, I know how it was taken off the board - it wasn't. They
>> just cut
>>> the board around it. I had to remove it myself. Nice thing about that,
>> is that
>>> I got a nice plastic, pre-formed part that fits between the board and the
>>> OCXO, probably as an insulator.
>>> 
>>> You are also right about the number of things that you need to test to
>> make
>>> sure that one of these is fully functional. However, this is a "starter"
>> OCXO
>>> for me and I don't yet have the equipment to perform the tests. The best
>> that
>>> I can do is to make sure that, when powered up
>>> 
>>>  1. I see something that sort of looks like a sine wave at a reasonable
>>> magnitude.
>>> 
>>>  2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz.
>>> 
>>>  3. If I apply gnd, or VRef to the adjustment pin I see the frequency
>> change
>>> at least a small amount.
>>> 
>>> Without more equipment, there isn't much more that I can do to test.
>> Unless
>>> you have some suggestions?
>>> 
>>> 
>>> Mike
>>> 
>>> 
 Hi
>>> 
 Best guess is these things get taken off the board with either a big
>> torch or a charcoal fire.
 You can ask Mr Google to dig up pictures of the process. Depending on
>> just how quick
 they are, the insides of the OCXO can easily be reflowed. The
>> likelihood of it reflowing and
 cooling back to a reliable joint … not real good.
>>> 
 Bob
>>> 
> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni 
>> wrote:
> 
> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:
> 
>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After
>> testing it,
>> it is clear that it is defective.
>> 
>> 1. It never heats up.
>> 2. The reference voltage is zero.
>> 3. Only noise is seen on the output pin.
> 
> I had the same issue with some of them. It's very likely that the
>> internal
> solder connections from pins to PCB are broken, at least, the one for
>> power.
> It happens because the inner oven is heavy and there isn't any thermal
> insulator (besides air) to keep it from moving.
> 
> Wheter the crystal has been damaged or not, it's unknown. I had one
>> where the
> crystal actually fell off from its supports too.
> 

Re: [time-nuts] MTI 260-0624-D OCXO

[Artek Manuals]

Bob is point on

Said another way ...few of us consider the value of our time in these 
projects ..Lets say your personal time is worth $50/hour (cheap cheap 
for a professional today) let's say you have to spend 10 hours testing 
this oscillator that puts the real cost of the oscillator at $500+  
suddenly some things don't look like such good bargains.


The other side of the coin is that if you learn something new about 
oscillators and their behavior and the supporting electronics circuitry 
 then $500 is a cheap educational seminar .


Dave
NR1DX



On 2/18/2016 7:09 AM, Bob Camp wrote:

Hi

It is*much*  better to have an OCXO that you do not need to test to death.
There is simply to much testing to do. A modern factory does not test the
quality into the product (of any sort) they design in and build it in. The same
is true of the normal customer for virtually any component. They make sure
the parts come from somebody they can trust and save a lot of testing time.

That said, yes, I have a pile of scrap parts sitting in front of me as I type 
this.
It’s a hobby. Time does not count. It lets me play with all sorts of toys doing
the testing. I occasionally learn things in the process. Mostly I learn that
my hope of a 100% perfect batch is still a dream ….

Bob



--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com

---
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Re: [time-nuts] MTI 260-0624-D OCXO

[Adrian Godwin]

I have a small collection of 10811 and similar oscillators here, collected
from hamfests rather than china (and mostly pre-ebay).

What sort of testing regime would you put them through ? I don't have
anything as exotic as a timepod but I do have an HP53131A, the Tait Rb
source, and a KS-24361 set up. And always keen to get hints on the
acquisition of new toys !



On Thu, Feb 18, 2016 at 12:09 PM, Bob Camp  wrote:

> Hi
>
> It is *much* better to have an OCXO that you do not need to test to death.
> There is simply to much testing to do. A modern factory does not test the
> quality into the product (of any sort) they design in and build it in. The
> same
> is true of the normal customer for virtually any component. They make sure
> the parts come from somebody they can trust and save a lot of testing time.
>
> That said, yes, I have a pile of scrap parts sitting in front of me as I
> type this.
> It’s a hobby. Time does not count. It lets me play with all sorts of toys
> doing
> the testing. I occasionally learn things in the process. Mostly I learn
> that
> my hope of a 100% perfect batch is still a dream ….
>
> Bob
>
>
>
> > On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote:
> >
> > Bob,
> >
> > In this case, I know how it was taken off the board - it wasn't. They
> just cut
> > the board around it. I had to remove it myself. Nice thing about that,
> is that
> > I got a nice plastic, pre-formed part that fits between the board and the
> > OCXO, probably as an insulator.
> >
> > You are also right about the number of things that you need to test to
> make
> > sure that one of these is fully functional. However, this is a "starter"
> OCXO
> > for me and I don't yet have the equipment to perform the tests. The best
> that
> > I can do is to make sure that, when powered up
> >
> >   1. I see something that sort of looks like a sine wave at a reasonable
> >  magnitude.
> >
> >   2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz.
> >
> >   3. If I apply gnd, or VRef to the adjustment pin I see the frequency
> change
> >  at least a small amount.
> >
> > Without more equipment, there isn't much more that I can do to test.
> Unless
> > you have some suggestions?
> >
> >
> > Mike
> >
> >
> >> Hi
> >
> >> Best guess is these things get taken off the board with either a big
> torch or a charcoal fire.
> >> You can ask Mr Google to dig up pictures of the process. Depending on
> just how quick
> >> they are, the insides of the OCXO can easily be reflowed. The
> likelihood of it reflowing and
> >> cooling back to a reliable joint … not real good.
> >
> >> Bob
> >
> >>> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni 
> wrote:
> >>>
> >>> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:
> >>>
>  I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After
> testing it,
>  it is clear that it is defective.
> 
>   1. It never heats up.
>   2. The reference voltage is zero.
>   3. Only noise is seen on the output pin.
> >>>
> >>> I had the same issue with some of them. It's very likely that the
> internal
> >>> solder connections from pins to PCB are broken, at least, the one for
> power.
> >>> It happens because the inner oven is heavy and there isn't any thermal
> >>> insulator (besides air) to keep it from moving.
> >>>
> >>> Wheter the crystal has been damaged or not, it's unknown. I had one
> where the
> >>> crystal actually fell off from its supports too.
> >>>
> >>> I posted a link to photos of the internals, time ago. The link is dead
> now
> >>> and I don't think to have the photos anymore but perhaps someone
> downloaded
> >>> them.
> >>>
> >>> Best regards,
> >>> Andrea Baldoni
> >>> ___
> >>> time-nuts mailing list -- time-nuts@febo.com
> >>> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >>> and follow the instructions there.
> >
> >> ___
> >> time-nuts mailing list -- time-nuts@febo.com
> >> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >
> >
> >
> > --
> > Best regards,
> > Timenutmailto:time...@metachaos.net
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

It is *much* better to have an OCXO that you do not need to test to death. 
There is simply to much testing to do. A modern factory does not test the
quality into the product (of any sort) they design in and build it in. The same
is true of the normal customer for virtually any component. They make sure
the parts come from somebody they can trust and save a lot of testing time.

That said, yes, I have a pile of scrap parts sitting in front of me as I type 
this.
It’s a hobby. Time does not count. It lets me play with all sorts of toys doing
the testing. I occasionally learn things in the process. Mostly I learn that 
my hope of a 100% perfect batch is still a dream ….

Bob 



> On Feb 17, 2016, at 9:56 PM, time...@metachaos.net wrote:
> 
> Bob,
> 
> In this case, I know how it was taken off the board - it wasn't. They just cut
> the board around it. I had to remove it myself. Nice thing about that, is that
> I got a nice plastic, pre-formed part that fits between the board and the
> OCXO, probably as an insulator.
> 
> You are also right about the number of things that you need to test to make
> sure that one of these is fully functional. However, this is a "starter" OCXO
> for me and I don't yet have the equipment to perform the tests. The best that
> I can do is to make sure that, when powered up
> 
>   1. I see something that sort of looks like a sine wave at a reasonable
>  magnitude.
> 
>   2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz.
> 
>   3. If I apply gnd, or VRef to the adjustment pin I see the frequency change
>  at least a small amount.
> 
> Without more equipment, there isn't much more that I can do to test. Unless
> you have some suggestions?
> 
> 
> Mike
> 
> 
>> Hi
> 
>> Best guess is these things get taken off the board with either a big torch 
>> or a charcoal fire.
>> You can ask Mr Google to dig up pictures of the process. Depending on just 
>> how quick
>> they are, the insides of the OCXO can easily be reflowed. The likelihood of 
>> it reflowing and
>> cooling back to a reliable joint … not real good. 
> 
>> Bob
> 
>>> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni  wrote:
>>> 
>>> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:
>>> 
 I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing 
 it,
 it is clear that it is defective.
 
  1. It never heats up.
  2. The reference voltage is zero.
  3. Only noise is seen on the output pin.
>>> 
>>> I had the same issue with some of them. It's very likely that the internal
>>> solder connections from pins to PCB are broken, at least, the one for power.
>>> It happens because the inner oven is heavy and there isn't any thermal
>>> insulator (besides air) to keep it from moving.
>>> 
>>> Wheter the crystal has been damaged or not, it's unknown. I had one where 
>>> the
>>> crystal actually fell off from its supports too.
>>> 
>>> I posted a link to photos of the internals, time ago. The link is dead now
>>> and I don't think to have the photos anymore but perhaps someone downloaded
>>> them.
>>> 
>>> Best regards,
>>> Andrea Baldoni
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to 
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
> 
>> ___
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>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> 
> 
> -- 
> Best regards,
> Timenutmailto:time...@metachaos.net
> 
> ___
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Re: [time-nuts] MTI 260-0624-D OCXO

[Alex Pummer]

Hi Mike,
look for any kind of radio-receiver, which would receive around 5MHz the 
old 60 meter broadcast ban, connect to power any kind of wire which 
could serve as antenna turn it on and try to find WWW at 5MHz, after 
that power up your 5MHz oscillator connect piece of wire to the 5 MHz 
output and bring the other end close to the radio receiver's "antenna" 
which you installed before. I you are lucky you will hear a beat from 
the radio's speaker, now you could apply some tuning voltage to your 
oscillator, and if you change that tuning voltage the beat will change 
somewhat but no to much since that OXCO has  very narrow tuning range. I 
t could also happen that you do not hear any beat frequency, but a 
wabling [= very low frequency fluctuation] of the www, because your 
oscillator's and the frequency of the  www are very close to each other, 
frequency of beat is not audible. the frequency of the www will be not 
exact since it's propagation path is not stabile. That is enough to see 
of the OXCO is still "alive" and with a proper PLL it could be tuned to 
the correct frequency

73
KJ6UHN
Alex

On 2/17/2016 6:56 PM, time...@metachaos.net wrote:

Bob,

In this case, I know how it was taken off the board - it wasn't. They just cut
the board around it. I had to remove it myself. Nice thing about that, is that
I got a nice plastic, pre-formed part that fits between the board and the
OCXO, probably as an insulator.

You are also right about the number of things that you need to test to make
sure that one of these is fully functional. However, this is a "starter" OCXO
for me and I don't yet have the equipment to perform the tests. The best that
I can do is to make sure that, when powered up

1. I see something that sort of looks like a sine wave at a reasonable
   magnitude.

2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz.

3. If I apply gnd, or VRef to the adjustment pin I see the frequency change
   at least a small amount.

Without more equipment, there isn't much more that I can do to test. Unless
you have some suggestions?


Mike



Hi
Best guess is these things get taken off the board with either a big torch or a 
charcoal fire.
You can ask Mr Google to dig up pictures of the process. Depending on just how 
quick
they are, the insides of the OCXO can easily be reflowed. The likelihood of it 
reflowing and
cooling back to a reliable joint … not real good.
Bob

On Feb 17, 2016, at 5:16 AM, Andrea Baldoni  wrote:

On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:


I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
it is clear that it is defective.

   1. It never heats up.
   2. The reference voltage is zero.
   3. Only noise is seen on the output pin.

I had the same issue with some of them. It's very likely that the internal
solder connections from pins to PCB are broken, at least, the one for power.
It happens because the inner oven is heavy and there isn't any thermal
insulator (besides air) to keep it from moving.

Wheter the crystal has been damaged or not, it's unknown. I had one where the
crystal actually fell off from its supports too.

I posted a link to photos of the internals, time ago. The link is dead now
and I don't think to have the photos anymore but perhaps someone downloaded
them.

Best regards,
Andrea Baldoni
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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

Bob,

In this case, I know how it was taken off the board - it wasn't. They just cut
the board around it. I had to remove it myself. Nice thing about that, is that
I got a nice plastic, pre-formed part that fits between the board and the
OCXO, probably as an insulator.

You are also right about the number of things that you need to test to make
sure that one of these is fully functional. However, this is a "starter" OCXO
for me and I don't yet have the equipment to perform the tests. The best that
I can do is to make sure that, when powered up

   1. I see something that sort of looks like a sine wave at a reasonable
  magnitude.

   2. My 2465B CT frequency counter thinks that it is somewhere near 5Mhz.

   3. If I apply gnd, or VRef to the adjustment pin I see the frequency change
  at least a small amount.

Without more equipment, there isn't much more that I can do to test. Unless
you have some suggestions?


Mike


> Hi

> Best guess is these things get taken off the board with either a big torch or 
> a charcoal fire.
> You can ask Mr Google to dig up pictures of the process. Depending on just 
> how quick
> they are, the insides of the OCXO can easily be reflowed. The likelihood of 
> it reflowing and
> cooling back to a reliable joint … not real good. 

> Bob

>> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni  wrote:
>> 
>> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:
>> 
>>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing 
>>> it,
>>> it is clear that it is defective.
>>> 
>>>   1. It never heats up.
>>>   2. The reference voltage is zero.
>>>   3. Only noise is seen on the output pin.
>> 
>> I had the same issue with some of them. It's very likely that the internal
>> solder connections from pins to PCB are broken, at least, the one for power.
>> It happens because the inner oven is heavy and there isn't any thermal
>> insulator (besides air) to keep it from moving.
>> 
>> Wheter the crystal has been damaged or not, it's unknown. I had one where the
>> crystal actually fell off from its supports too.
>> 
>> I posted a link to photos of the internals, time ago. The link is dead now
>> and I don't think to have the photos anymore but perhaps someone downloaded
>> them.
>> 
>> Best regards,
>> Andrea Baldoni
>> ___
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-- 
Best regards,
 Timenutmailto:time...@metachaos.net

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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

Best guess is these things get taken off the board with either a big torch or a 
charcoal fire. 
You can ask Mr Google to dig up pictures of the process. Depending on just how 
quick 
they are, the insides of the OCXO can easily be reflowed. The likelihood of it 
reflowing and
cooling back to a reliable joint … not real good. 

Bob

> On Feb 17, 2016, at 5:16 AM, Andrea Baldoni  wrote:
> 
> On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:
> 
>> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing 
>> it,
>> it is clear that it is defective.
>> 
>>   1. It never heats up.
>>   2. The reference voltage is zero.
>>   3. Only noise is seen on the output pin.
> 
> I had the same issue with some of them. It's very likely that the internal
> solder connections from pins to PCB are broken, at least, the one for power.
> It happens because the inner oven is heavy and there isn't any thermal
> insulator (besides air) to keep it from moving.
> 
> Wheter the crystal has been damaged or not, it's unknown. I had one where the
> crystal actually fell off from its supports too.
> 
> I posted a link to photos of the internals, time ago. The link is dead now
> and I don't think to have the photos anymore but perhaps someone downloaded
> them.
> 
> Best regards,
> Andrea Baldoni
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Re: [time-nuts] MTI 260-0624-D OCXO

[timenut]

The vendor is resending it. He has not said what he wants done with the dead
one. Probably nothing, in which case I will tear it apart. Probably won't fix
anything, but at least I'll get a good look inside. And the SC crystal could
always be used in a custom DOCXO.


Mike


> I've had essentially the same experience with a batch of 34310-Ts that I
> got from China.  Some are very good, most are good enough, some work but are
> useless for anything serious.  I haven't gone through enough of them to get
> any feel for the waste rate.  Hopefully it won't be more than 2 out of 10.

> Bob

> 
> On Tue, 2/16/16, Bob Camp <kb...@n1k.org> wrote:

>  Subject: Re: [time-nuts] MTI 260-0624-D OCXO
>  To: time...@metachaos.net, "Discussion of precise time and frequency 
> measurement" <time-nuts@febo.com>
>  Date: Tuesday, February 16, 2016, 8:27 PM
>  
>  Hi
>  
>  The 260’s that I have seen from inside the
>  USA have been pretty good (not perfect, but
>  certainly not dead). Most of the issues have
>  been quibbles. Phase noise not quite in spec. 
>  ADEV not quite as good as it might have been.
>  
>  
>  Everything I have seen so
>  far from China (260 or not) has been very hit or 
>  miss. Stuff that is called “scrap for parts
>  only” (like a pile of 10 Rb’s I have here) may turn
>  up more working parts than something labeled
>  “great / tested / buy now / first best great 
>  product (a direct quote)“. I have tried the
>  “buy a few and then go back” approach. There 
>  has been little correlation between what I got
>  the second time and what came in first. My
>  conclusion (often stated) is that the salvage
>  process over there is pretty brutal. 
>  
>  Bob
>  
 >> On
>  Feb 16, 2016, at 7:58 PM, time...@metachaos.net
>  wrote:
 >> 
 >> I just
>  received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After
>  testing it,
 >> it is clear that it is
>  defective.
 >> 
 >>   1. It never heats up.
 >> 
 >>   2. The
>  reference voltage is zero.
 >> 
 >>   3. Only noise is seen on the
>  output pin.
 >> 
 >> I
>  tested with a 12.54V, 2A supply voltage with around 30mV
>  noise. That should
 >> be sufficient to
>  test.
 >> 
 >> All I was
>  looking for was a 5Mhz signal whose frequency changed when
>  the
 >> adjustment pin was either tied to
>  ground or the reference voltage. Never got
 >> that far because I never go a signal at
>  all.
 >> 
 >> The seller
>  packed it well and shipped it promptly. I will see how he
>  handles
 >> it.
 >> 
 >> 
 >> Mike
 >> 
 >>
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 >> time-nuts mailing list -- time-nuts@febo.com
 >> To unsubscribe, go to 
 >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 >> and follow the instructions there.
>  
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-- 
Best regards,
 Timenutmailto:time...@metachaos.net

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Re: [time-nuts] MTI 260-0624-D OCXO

[Andrea Baldoni]

On Tue, Feb 16, 2016 at 07:58:21PM -0500, time...@metachaos.net wrote:

> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
> it is clear that it is defective.
> 
>1. It never heats up.
>2. The reference voltage is zero.
>3. Only noise is seen on the output pin.

I had the same issue with some of them. It's very likely that the internal
solder connections from pins to PCB are broken, at least, the one for power.
It happens because the inner oven is heavy and there isn't any thermal
insulator (besides air) to keep it from moving.

Wheter the crystal has been damaged or not, it's unknown. I had one where the
crystal actually fell off from its supports too.

I posted a link to photos of the internals, time ago. The link is dead now
and I don't think to have the photos anymore but perhaps someone downloaded
them.

Best regards,
Andrea Baldoni
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

What I have found on all of these is that the harder you look, the more you
toss out. I get a lot more from some batches than others to this or that point
in the testing. In some groups > 80% of them do not have working ovens or 
an output > 0 dbm. 

There are no hard specs on these surplus units (they are OEM specs). What
numbers should you check to past that? If you have a copy of that confidential
spec, how close is it to the general spec? Who knows. It would appear that in 
a lot of cases the “part number” refers to a package size and pinout. Past that
the other numbers are negotiable. 

If the objective is that magic sub 1x10^-12 ADEV from 0.1 second
out to 1,000 seconds ….. you will be sorting for a long time. Even at 3x10^-12 
over
that entire range, you will sort a lot. Switch specs and just look at 1x10^-8
TC over -20 to +70, there is a lot of sorting to do. Same things with phase
noise, aging, harmonics, … on and on.

With the surplus stuff from China a sort seems to be the only way to do it. 
Either
you buy stuff that has been sorted over there or you sort it yourself. The 
testing 
involved in the more detailed specs is tough enough that the process can get
pretty complex. If there is somebody over there you can be *sure* is doing a 
full
test … I have not found them yet. 

Bob


> On Feb 16, 2016, at 10:49 PM, Bob Stewart <b...@evoria.net> wrote:
> 
> Hi Bob,
> 
> I've had essentially the same experience with a batch of 34310-Ts that I got 
> from China.  Some are very good, most are good enough, some work but are 
> useless for anything serious.  I haven't gone through enough of them to get 
> any feel for the waste rate.  Hopefully it won't be more than 2 out of 10.
> 
> Bob
> 
> 
> On Tue, 2/16/16, Bob Camp <kb...@n1k.org> wrote:
> 
> Subject: Re: [time-nuts] MTI 260-0624-D OCXO
> To: time...@metachaos.net, "Discussion of precise time and frequency 
> measurement" <time-nuts@febo.com>
> Date: Tuesday, February 16, 2016, 8:27 PM
> 
> Hi
> 
> The 260’s that I have seen from inside the
> USA have been pretty good (not perfect, but
> certainly not dead). Most of the issues have
> been quibbles. Phase noise not quite in spec. 
> ADEV not quite as good as it might have been.
> 
> 
> Everything I have seen so
> far from China (260 or not) has been very hit or 
> miss. Stuff that is called “scrap for parts
> only” (like a pile of 10 Rb’s I have here) may turn
> up more working parts than something labeled
> “great / tested / buy now / first best great 
> product (a direct quote)“. I have tried the
> “buy a few and then go back” approach. There 
> has been little correlation between what I got
> the second time and what came in first. My
> conclusion (often stated) is that the salvage
> process over there is pretty brutal. 
> 
> Bob
> 
>> On
> Feb 16, 2016, at 7:58 PM, time...@metachaos.net
> wrote:
>> 
>> I just
> received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After
> testing it,
>> it is clear that it is
> defective.
>> 
>>1. It never heats up.
>> 
>>2. The
> reference voltage is zero.
>> 
>>3. Only noise is seen on the
> output pin.
>> 
>> I
> tested with a 12.54V, 2A supply voltage with around 30mV
> noise. That should
>> be sufficient to
> test.
>> 
>> All I was
> looking for was a 5Mhz signal whose frequency changed when
> the
>> adjustment pin was either tied to
> ground or the reference voltage. Never got
>> that far because I never go a signal at
> all.
>> 
>> The seller
> packed it well and shipped it promptly. I will see how he
> handles
>> it.
>> 
>> 
>> Mike
>> 
>> 
> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Stewart]

Hi Bob,

I've had essentially the same experience with a batch of 34310-Ts that I got 
from China.  Some are very good, most are good enough, some work but are 
useless for anything serious.  I haven't gone through enough of them to get any 
feel for the waste rate.  Hopefully it won't be more than 2 out of 10.

Bob


On Tue, 2/16/16, Bob Camp <kb...@n1k.org> wrote:

 Subject: Re: [time-nuts] MTI 260-0624-D OCXO
 To: time...@metachaos.net, "Discussion of precise time and frequency 
measurement" <time-nuts@febo.com>
 Date: Tuesday, February 16, 2016, 8:27 PM
 
 Hi
 
 The 260’s that I have seen from inside the
 USA have been pretty good (not perfect, but
 certainly not dead). Most of the issues have
 been quibbles. Phase noise not quite in spec. 
 ADEV not quite as good as it might have been.
 
 
 Everything I have seen so
 far from China (260 or not) has been very hit or 
 miss. Stuff that is called “scrap for parts
 only” (like a pile of 10 Rb’s I have here) may turn
 up more working parts than something labeled
 “great / tested / buy now / first best great 
 product (a direct quote)“. I have tried the
 “buy a few and then go back” approach. There 
 has been little correlation between what I got
 the second time and what came in first. My
 conclusion (often stated) is that the salvage
 process over there is pretty brutal. 
 
 Bob
 
 > On
 Feb 16, 2016, at 7:58 PM, time...@metachaos.net
 wrote:
 > 
 > I just
 received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After
 testing it,
 > it is clear that it is
 defective.
 > 
 >   1. It never heats up.
 > 
 >   2. The
 reference voltage is zero.
 > 
 >   3. Only noise is seen on the
 output pin.
 > 
 > I
 tested with a 12.54V, 2A supply voltage with around 30mV
 noise. That should
 > be sufficient to
 test.
 > 
 > All I was
 looking for was a 5Mhz signal whose frequency changed when
 the
 > adjustment pin was either tied to
 ground or the reference voltage. Never got
 > that far because I never go a signal at
 all.
 > 
 > The seller
 packed it well and shipped it promptly. I will see how he
 handles
 > it.
 > 
 > 
 > Mike
 > 
 >
 ___
 > time-nuts mailing list -- time-nuts@febo.com
 > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 > and follow the instructions there.
 
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Re: [time-nuts] MTI 260-0624-D OCXO

[Bob Camp]

Hi

The 260’s that I have seen from inside the USA have been pretty good (not 
perfect, but
certainly not dead). Most of the issues have been quibbles. Phase noise not 
quite in spec. 
ADEV not quite as good as it might have been. 

Everything I have seen so far from China (260 or not) has been very hit or 
miss. Stuff that is called “scrap for parts only” (like a pile of 10 Rb’s I 
have here) may turn
up more working parts than something labeled “great / tested / buy now / first 
best great 
product (a direct quote)“. I have tried the “buy a few and then go back” 
approach. There 
has been little correlation between what I got the second time and what came in 
first. My
conclusion (often stated) is that the salvage process over there is pretty 
brutal. 

Bob

> On Feb 16, 2016, at 7:58 PM, time...@metachaos.net wrote:
> 
> I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
> it is clear that it is defective.
> 
>   1. It never heats up.
> 
>   2. The reference voltage is zero.
> 
>   3. Only noise is seen on the output pin.
> 
> I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
> be sufficient to test.
> 
> All I was looking for was a 5Mhz signal whose frequency changed when the
> adjustment pin was either tied to ground or the reference voltage. Never got
> that far because I never go a signal at all.
> 
> The seller packed it well and shipped it promptly. I will see how he handles
> it.
> 
> 
> Mike
> 
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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[time-nuts] MTI 260-0624-D OCXO

[timenut]

I just received a 5Mhz OCXO from eBay (MTI 260-0624-D OCXO). After testing it,
it is clear that it is defective.

   1. It never heats up.

   2. The reference voltage is zero.

   3. Only noise is seen on the output pin.

I tested with a 12.54V, 2A supply voltage with around 30mV noise. That should
be sufficient to test.

All I was looking for was a 5Mhz signal whose frequency changed when the
adjustment pin was either tied to ground or the reference voltage. Never got
that far because I never go a signal at all.

The seller packed it well and shipped it promptly. I will see how he handles
it.


Mike

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