Traced the problem of my FTS 1200 to the first BC109 Transistor on the
A2/A3 AGS/Amplifier board. Since it is right after the Oscillator transistor
low noise is critical. This unit is at least 30 years old and my question is,
what transistor will have even lower noise than the than low noise
Hi
The 2N5089 from ON semi is a pretty good bet for a high beta / audio part. They
are $0.37 a piece from Mouser with 11,542 in stock.
Bob
On May 17, 2014, at 11:37 AM, ewkeh...@aol.com wrote:
Traced the problem of my FTS 1200 to the first BC109 Transistor on the
A2/A3 AGS/Amplifier
Bert wrote:
what transistor will have even lower noise than the than low noise BC 109.
Generally speaking, the baseband noise of a bipolar transistor is
most strongly influenced by the transistor's base spreading
resistance. Of course, the transistor also needs to have whatever
other
Thanks for all the help. I do have a couple of BC 109 but I thought with
all the work to carefully disassemble the unit that after 30 years there
would be a better transistor.
Thanks again
Bert Kehren
In a message dated 5/17/2014 6:47:55 P.M. Eastern Daylight Time,
csteinm...@yandex.com
Thanks for all the help. I do have a couple of BC 109 but I thought with
all the work to carefully disassemble the unit that after 30 years there
would be a better transistor.
The fundamentals of solid state physics haven't changed much in 30
years;-)
It's a tribute to
Does any one have the schematic of a FTS 1200 OCXO ?
Thanks Bert Kehren Miami
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Bert,
Good that you got the EFC working! But I would be a bit suspicious of
needing -13V.
It seems from:
http://www.ece.gatech.edu/academic/courses/ece4007/08fall/ece4007l01/al4/datasheets/symmetricon_oscillator_instructionsheet.pdf
that the default EFC configuration is (0 to +10)V with a
Bjoern
Thank you for the link I am able to change the frequency 4 Hz from - 2Hz (
0V) to + 2 Hz (-12.2V) using pin 2. Reading the info that you got me
probably explains the slot next to the connector, but I experience a much wider
tuning range on pin 2 and John is right any positive
Hi Bert,
I see on the data sheet that the tuning voltage is supposed to be -10 to
+10 volts and that the supply voltage is +22 to +30 volts. I suspect
that one side of the varactor is supposed to be biased at one half of
the supply voltage. But in your case, it looks like that bias is now
Ed
I did not see any current, but that is also due to the fact that there is
most likely at least 10 K between pin 2 and the varactor. Most likely if it
was biased for instance + 12 Volt, there would also be a resistor before
the diode. I suspect John is right that with my + voltage the
From slowly working my way thru several new to me datum 1000's I'm coming to
the conclusion that powering them up checking for output and basic
functionality (ie can the frequency be adjusted ?) followed by leaving them
alone and powered up for several weeks to a month or so is probably the
Bert,
I wasn't suggesting amps of current. A normal reverse-biased diode
would give nanoamps of current flowing out. Microamps (or more) of
current flowing in would show that the internal biasing of the varactor
was messed up. A bad diode could also show current flowing in, but your
Ed
I think so too. I hope if it is a shorted capacitor it stays but looking at
for instance at the bias of a 10811. There would be no capacitor right at
the diode. I have the tuning network for a 1130 and it shows a 20 K to an
internal +12 V
Bert
In a message dated 8/10/2012 2:01:22 P.M.
Hi
Normally when you forward bias a varicap, nothing strange happens. The
capacitance goes way up as it goes forward and then it pretty much turns into
an RF short circuit. The series resistance of the device drops considerably as
this all takes place. If it's in series with the crystal, the
I have a FTS 1200 that is off by about 2 Hz. Have decided to take a
closer look. Does any one have technical Information I should study before I
open it up.
Thanks
Bert Kehren
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Subject: [time-nuts] FTS 1200
To: time-nuts@febo.com
Received: Thursday, August 9, 2012, 5:00 PM
I have a FTS 1200 that is off by
about 2 Hz. Have decided to take a
closer look. Does any one have technical Information I
should study before I
open it up.
Thanks
Bert Kehren
weeks.
Regards
Mark Spencer
--- On Thu, 8/9/12, ewkeh...@aol.com ewkeh...@aol.com wrote:
From: ewkeh...@aol.com ewkeh...@aol.com
Subject: [time-nuts] FTS 1200
To: time-nuts@febo.com
Received: Thursday, August 9, 2012, 5:00 PM
I have a FTS 1200 that is off by
about 2 Hz. Have decided
Hi Bert,
I have a FTS 1200 that is off by about 2 Hz. Have decided to take a
closer look. Does any one have technical Information I should study
before I
open it up.
Thanks
Bert Kehren
The efc range on my FTS 1200 goes from about -1.5Hz to +2Hz (0V to +10V).
Is your FTS1200 of even with
Bjoern
No not able to tune it to 5 MHz.
Bert
In a message dated 8/9/2012 6:48:59 P.M. Eastern Daylight Time,
b...@lysator.liu.se writes:
Hi Bert,
I have a FTS 1200 that is off by about 2 Hz. Have decided to take a
closer look. Does any one have technical Information I should study
Hi
As the unit warms up, you should be able to tell weaner it starts off above 5
or below 5 MHz. There are enough different crystal cuts that *might* be in
there that checking it at turn on is the easy approach. If it starts low and is
off low, the heater may be the issue.
Bob
On Aug 9,
The unit starts high and over 20 minutes comes down to 4.975 with 0 V
on the EFC. Any voltage on pin 2 and it quits oscillating.
Bert
In a message dated 8/9/2012 7:06:48 P.M. Eastern Daylight Time,
li...@rtty.us writes:
Hi
As the unit warms up, you should be able to tell weaner it
Hi
Best bet is a bad solder joint. Likely on the crystal it's self. Of course it
could be on anything in series with the crystal.
Bob
On Aug 9, 2012, at 7:49 PM, ewkeh...@aol.com wrote:
The unit starts high and over 20 minutes comes down to 4.975 with 0 V
on the EFC. Any voltage on
Hi Bert,
So the EFC does not work at all? (or did I miss something obvious?)
/Björn
The unit starts high and over 20 minutes comes down to 4.975 with 0 V
on the EFC. Any voltage on pin 2 and it quits oscillating.
Bert
In a message dated 8/9/2012 7:06:48 P.M. Eastern Daylight Time,
Bjoern
No EFC. The moment I even put a small Voltage like 0.9 V through a 33 K
resistor on pin 2 it quits oscillating.
Bert
In a message dated 8/9/2012 8:07:24 P.M. Eastern Daylight Time,
b...@lysator.liu.se writes:
Hi Bert,
So the EFC does not work at all? (or did I miss something
Hi Bert,
My guess would be a bad (shorted maybe?) Varicap. Does it go out of oscillation
if you just ground the efc pin ?
BillWB6BNQ
ewkeh...@aol.com wrote:
Bjoern
No EFC. The moment I even put a small Voltage like 0.9 V through a 33 K
resistor on pin 2 it quits oscillating.
Bert
In a message dated 8/9/2012 8:07:24 P.M. Eastern Daylight Time,
b...@lysator.liu.se writes:
Hi Bert,
So the EFC does not work at all? (or did I miss something obvious?)
/Björn
The unit starts high and over 20 minutes comes down to 4.975 with 0
V
on the EFC. Any voltage on
Bill
Grounded pin, works and stays on frequency.
Bert
In a message dated 8/9/2012 8:29:08 P.M. Eastern Daylight Time,
wb6...@cox.net writes:
Hi Bert,
My guess would be a bad (shorted maybe?) Varicap. Does it go out of
oscillation
if you just ground the efc pin ?
BillWB6BNQ
John
Oven did reduce in current and I can not imagine that it would be that
close with an overheated oven. At 0 V it is within .5 Hz of what they normally
are. Ground has no effect but even 0.8 V on pin 2 stops oscillation
Once it stops it takes about 10 seconds to continue oscillation, about
John
Oven did reduce in current and I can not imagine that it would be that
close with an overheated oven. At 0 V it is within .5 Hz of what they
normally
are. Ground has no effect but even 0.8 V on pin 2 stops oscillation
That's a suspicious-sounding voltage. Are you sure you're not
John,
that did the trick I can tune it with a negative voltage, minus 13 gives
me plus 2 Hz but this unit came out of a FTS 5000 and it had a positive
tuning voltage.
Bert
In a message dated 8/9/2012 9:13:29 P.M. Eastern Daylight Time,
jmi...@pop.net writes:
John
Oven did reduce in
John
Thanks again I am calling it a night. Will let it soak over night and
continue tests in the morning. Does any one have the oscillator circuit. With
the connector on the bottom left to the right id something that looks like
an adjustment screw,flat round flush with the surface and a
Forgot to mention the FTS 1200 oscillator on eBay right now!
Corby Dawson
Need cash? Click to get a loan.
http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTFRc5hEnCdmeYppreg2sNh7b9xRu81AoDczVpjBR4PVYw2PsHkLiI/
The cat's out of the bag!
2009/9/17 Corby Dawson cdel...@juno.com:
Forgot to mention the FTS 1200 oscillator on eBay right now!
Corby Dawson
Need cash? Click to get a loan.
Hi,
As promised here is a heads up on the sale of an FTS 1200 oscillator eBay
320349664178
There will be a few more if it sells so keep an eye out.
On another topic is there anyone out there that would be willing to help
modify Brooks Sheras
Pic code to incorporate some modifications to the
Dawson cdel...@juno.com wrote:
From: Corby Dawson cdel...@juno.com
Subject: [time-nuts] FTS 1200 9110 1000A-100 1000B pinouts here!
To: time-nuts@febo.com
Received: Sunday, 1 March, 2009, 1:02 AM
Well after re-researcing the pinouts again I decided to post this while
they are fresh.
These Pinouts
and frequency measurement time-nuts@febo.com
Cc: ang...@dodo.com.au
Subject: Re: [time-nuts] FTS 1200 9110 1000A-100 1000B pinouts here!
Hi Time Keepers
Not quite an answer to the below question , but my own request for TCXO
pinout info
on my recent purchase on Ebay.
The TCXO unit was designated to go
Well after re-researcing the pinouts again I decided to post this while
they are fresh.
These Pinouts are for units removed from FTS Cesium standards and were
verified by measurement in the standard.
PIN1000B1000A-1001200
9110
1
Hi,
Here are some results of the FTS 1200 and FTS 9110 oscillators I have
recently tested.
1SEC 10SEC100SEC
1200 1 7.14-13 1.48-12 1.92-12
1200 2 3.29-13 1.80-13 3.28-13
1 and 2 above previously tested
1200 1B 4.00-13 5.50-13
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