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
>
>> Anythi
> 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
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
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.
Mik
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 th
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
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
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 appe
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
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.
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
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 t
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 reassemble
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.
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 kill
ailto: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
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 c
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
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
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 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
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 l
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 coul
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
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 m
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
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
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+
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
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
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
outpu
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
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
27;t be more than 2 out of 10.
> Bob
>
> On Tue, 2/16/16, Bob Camp wrote:
> Subject: Re: [time-nuts] MTI 260-0624-D OCXO
> To: time...@metachaos.net, "Discussion of precise time and frequency
> measurement"
> Date: Tuesda
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
--
> On Tue, 2/16/16, Bob Camp wrote:
>
> Subject: Re: [time-nuts] MTI 260-0624-D OCXO
> To: time...@metachaos.net, "Discussion of precise time and frequency
> measurement"
> Date: Tuesday, February 16, 2016, 8:27 PM
>
> Hi
>
> The 260’s th
't be more than 2 out of 10.
Bob
On Tue, 2/16/16, Bob Camp wrote:
Subject: Re: [time-nuts] MTI 260-0624-D OCXO
To: time...@metachaos.net, "Discussion of precise time and frequency
measurement"
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 ver
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 shoul
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