Empathy List Archives

JC

Jared Cabot

Thu, Dec 2, 2021 9:57 AM

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.

On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...

I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...

I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.

I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.

Jared.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? Jared. ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts <time-nuts@lists.febo.com> wrote: > Don't give up now, Jared! You must be so close to getting that puppy running correctly. > > On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: > > > Well, yay... > > > > I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... > > > > I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. > > > > I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. > > > > Jared. > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there.

JC

Jared Cabot

Thu, Dec 2, 2021 12:04 PM

Latest update.

Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point.
Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it.

(I attached the schematic, hopefully it shows up ok).

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.

On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...

I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...

I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.

I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.

Jared.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there._______________________________________________

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

Latest update. Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point. Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it. (I attached the schematic, hopefully it shows up ok). Jared ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts <time-nuts@lists.febo.com> wrote: > Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) > > Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? > > Jared. > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote: > > > Don't give up now, Jared! You must be so close to getting that puppy running correctly. > > > On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: > > > > Well, yay... > > > > I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... > > > > I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. > > > > I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. > > > > Jared. > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > > To unsubscribe, go to and follow the instructions there._______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > To unsubscribe, go to and follow the instructions there.

JC

Jared Cabot

Thu, Dec 2, 2021 2:15 PM

So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason.
Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V).
I can find a 5% 9V (1N936A), but the 11V is harder to find.

Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway.....

Schematics attached for reference.

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 21:04, Jared Cabot jaredcabot@protonmail.com wrote:

Latest update.

Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point.

Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it.

(I attached the schematic, hopefully it shows up ok).

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.

On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...

I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...

I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.

I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.

Jared.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there._______________________________________________

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason. Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V). I can find a 5% 9V (1N936A), but the 11V is harder to find. Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway..... Schematics attached for reference. Jared ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ On Thursday, December 2nd, 2021 at 21:04, Jared Cabot <jaredcabot@protonmail.com> wrote: > Latest update. > > Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point. > > Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it. > > (I attached the schematic, hopefully it shows up ok). > > Jared > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote: > > > Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) > > > > Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? > > > > Jared. > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote: > > > > > Don't give up now, Jared! You must be so close to getting that puppy running correctly. > > > > > On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: > > > > > > Well, yay... > > > > > > I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... > > > > > > I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. > > > > > > I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. > > > > > > Jared. > > > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > > > > To unsubscribe, go to and follow the instructions there._______________________________________________ > > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > > > To unsubscribe, go to and follow the instructions there.

BK

Bob kb8tq

Thu, Dec 2, 2021 2:25 PM

Hi

Since you can “dial in” the correct voltage, I’d go with the parts you
can find. I’d be suspicious that all those parts died and the transformer
is still healthy …..

Bob

On Dec 2, 2021, at 9:15 AM, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason.
Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V).
I can find a 5% 9V (1N936A), but the 11V is harder to find.

Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway.....

Schematics attached for reference.

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 21:04, Jared Cabot jaredcabot@protonmail.com wrote:

Latest update.

Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point.

Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it.

(I attached the schematic, hopefully it shows up ok).

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.

On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...

I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...

I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.

I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.

Jared.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there._______________________________________________

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there.

<A15 Power Supply and Regulator Assembly Schematic.png>_______________________________________________
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To unsubscribe, go to and follow the instructions there.

Hi Since you can “dial in” the correct voltage, I’d go with the parts you can find. I’d be suspicious that all those parts died and the transformer is still healthy ….. Bob > On Dec 2, 2021, at 9:15 AM, Jared Cabot via time-nuts <time-nuts@lists.febo.com> wrote: > > So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason. > Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V). > I can find a 5% 9V (1N936A), but the 11V is harder to find. > > Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway..... > > Schematics attached for reference. > > > > Jared > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Thursday, December 2nd, 2021 at 21:04, Jared Cabot <jaredcabot@protonmail.com> wrote: > >> Latest update. >> > >> Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point. >> > >> Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it. >> > >> (I attached the schematic, hopefully it shows up ok). >> > >> Jared >> > >> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ >> > >> On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote: >> > >>> Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) >>> > >>> Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? >>> > >>> Jared. >>> > >>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ >>> > >>> On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote: >>> > >>>> Don't give up now, Jared! You must be so close to getting that puppy running correctly. >>> > >>>> On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: >>> > >>>>> Well, yay... >>> > >>>>> I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... >>> > >>>>> I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. >>> > >>>>> I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. >>> > >>>>> Jared. >>> > >>>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >>> > >>>> To unsubscribe, go to and follow the instructions there._______________________________________________ >>> > >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >>> > >>> To unsubscribe, go to and follow the instructions there. > <A15 Power Supply and Regulator Assembly Schematic.png>_______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > To unsubscribe, go to and follow the instructions there.

HP

Henk Peek

Thu, Dec 2, 2021 6:20 PM

Jared,

I think an -20 V rail short to ground has first blowup A15Q10.
Then the -20V converter was light loaded and the output DC voltage goes up and blows also the zeners.
The most easy way to protect and repair: replace A15Q10 with a LM337 with 2 resistors to adjust the output to -20V.
Remove the blown zeners and diode and mount the 2 resistors on the removed zener positions.

Regards, Henk

On Thursday, December 02, 2021 15:15 CET, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason.
Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V).
I can find a 5% 9V (1N936A), but the 11V is harder to find.

Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway.....

Schematics attached for reference.

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 21:04, Jared Cabot jaredcabot@protonmail.com wrote:

Latest update.

Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point.

Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it.

(I attached the schematic, hopefully it shows up ok).

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.

On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...

I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...

I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.

I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.

Jared.

time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

To unsubscribe, go to and follow the instructions there._______________________________________________

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Jared, I think an -20 V rail short to ground has first blowup A15Q10. Then the -20V converter was light loaded and the output DC voltage goes up and blows also the zeners. The most easy way to protect and repair: replace A15Q10 with a LM337 with 2 resistors to adjust the output to -20V. Remove the blown zeners and diode and mount the 2 resistors on the removed zener positions. Regards, Henk On Thursday, December 02, 2021 15:15 CET, Jared Cabot via time-nuts <time-nuts@lists.febo.com> wrote: > So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason. > Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V). > I can find a 5% 9V (1N936A), but the 11V is harder to find. > > Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway..... > > Schematics attached for reference. > > > > Jared > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Thursday, December 2nd, 2021 at 21:04, Jared Cabot <jaredcabot@protonmail.com> wrote: > > > Latest update. > > > > Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point. > > > > Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it. > > > > (I attached the schematic, hopefully it shows up ok). > > > > Jared > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote: > > > > > Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) > > > > > > Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? > > > > > > Jared. > > > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > > > > > On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote: > > > > > > > Don't give up now, Jared! You must be so close to getting that puppy running correctly. > > > > > > > On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: > > > > > > > > Well, yay... > > > > > > > > I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... > > > > > > > > I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. > > > > > > > > I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. > > > > > > > > Jared. > > > > > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > > > > > > To unsubscribe, go to and follow the instructions there._______________________________________________ > > > > > > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com > > > > > > To unsubscribe, go to and follow the instructions there.

MD

Magnus Danielson

Thu, Dec 2, 2021 10:49 PM

Hi Jared,

One of my 5065's have exactly this fault.

One approach is to rebuild with a new power inverter. Another is to
rebuild the amplifier board so it does not need -20 V and can operate
only on +20 V.

There should be DC-DC inverters, but I failed to grab a suitable
pre-built board for it.

I would enjoy not having to hear the 3.5 kHz switching frequency in my lab.

Cheers,
Magnus

Den 2021-12-02 kl. 15:15, skrev Jared Cabot via time-nuts:

So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason.
Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V).
I can find a 5% 9V (1N936A), but the 11V is harder to find.

Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway.....

Schematics attached for reference.

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 21:04, Jared Cabot jaredcabot@protonmail.com wrote:

Latest update.

Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point.

Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it.

(I attached the schematic, hopefully it shows up ok).

Jared

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote:

Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level)

Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check?

Jared.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐

On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote:

Don't give up now, Jared! You must be so close to getting that puppy running correctly.
On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote:

Well, yay...
I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back...
I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working.
I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time.
Jared.
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com
To unsubscribe, go to and follow the instructions there._______________________________________________
time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com

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To unsubscribe, go to and follow the instructions there.

Hi Jared, One of my 5065's have exactly this fault. One approach is to rebuild with a new power inverter. Another is to rebuild the amplifier board so it does not need -20 V and can operate only on +20 V. There should be DC-DC inverters, but I failed to grab a suitable pre-built board for it. I would enjoy not having to hear the 3.5 kHz switching frequency in my lab. Cheers, Magnus Den 2021-12-02 kl. 15:15, skrev Jared Cabot via time-nuts: > So it looks like I lost the -20V rail. Seems that A15Q10 (2N4234), A10CR9A (9V Zener), and A15CR9B (11V Zener) are all dead for some reason. > Q10 is easy enought o find, but the zeners are a little more tricky, they are specified as part number 1902-0247, a 20V, 1%, 0.4W +0.005%TC zener (20V made up of the 9v + 11V). > I can find a 5% 9V (1N936A), but the 11V is harder to find. > > Maybe I should look into redesigning this board entirely, the transformer on mine is rather noisy anyway..... > > Schematics attached for reference. > > > > Jared > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Thursday, December 2nd, 2021 at 21:04, Jared Cabot <jaredcabot@protonmail.com> wrote: > >> Latest update. >> >> Looks like I'm getting 2.76VDC out of A7J1 and I can't adjust it with A7R3. According to the manual, it should be less than 50mV.. I was able to set this to around 0.5mV previously, so it did work at one point. >> >> Q1 and Q2 test ok on my ebay component tester, IC1 is a selected uA741TC, but I'm not sure how to effectively test it. >> >> (I attached the schematic, hopefully it shows up ok). >> >> Jared >> >> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ >> >> On Thursday, December 2nd, 2021 at 18:57, Jared Cabot via time-nuts time-nuts@lists.febo.com wrote: >> >>> Well, it seems more digging is needed... I have 84uA Photo I coming from the RVFR on A7P1, but the front panel is at 14 (Should be 42 for my Photo I level) >>> >>> Manual says look at Q1, Q2 and IC1 circuits. Anyone have any pointers or suggestions on what to check? >>> >>> Jared. >>> >>> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ >>> >>> On Thursday, December 2nd, 2021 at 17:21, Andy Gardner, ZL3AG via time-nuts time-nuts@lists.febo.com wrote: >>> >>>> Don't give up now, Jared! You must be so close to getting that puppy running correctly. >>>> On 2/12/21 9:16 pm, Jared Cabot via time-nuts wrote: >>>>> Well, yay... >>>>> I put the OCXO back in the 5065A, and got a good 2nd Harmonic reading. So I started going through the alignment procedures and somehow I now have no 2nd harmonic again, and I can't get it back... >>>>> I'm starting to lose interest in this thing, seeing as I have the Leo Bodnar GPS standard anyway that I don't have to sit for hours twiddling dials and poking things just to get it maybe sort of working. >>>>> I might give this one more chance before I sell it off to someone with a little more patience, or who prefers fixing gear instead of actually using it. I think I've had this thing working for all of a couple days in the months I've owned it, whereas the GPS standard is the size of a pack of cards and has never failed in the same time. >>>>> Jared. >>>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >>>> To unsubscribe, go to and follow the instructions there._______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >>> >>> To unsubscribe, go to and follow the instructions there. >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-leave@lists.febo.com >>> To unsubscribe, go to and follow the instructions there.

LM

Larry McDavid

Fri, Dec 3, 2021 2:56 AM

Try as I might, I cannot hear a single thing from my 5065A, which has
run 24/7 for five years without issue.

Jared earlier said he has inverter noise from his 5065A and now Magnus
reports it also. How common is this?

I will be interested in a replacement A15 regulator board as Ulf
Kylenfall SM6GXV described. Let's allow Ulf to build and test the PWBs
he receives and then some kind of group buy could be arranged.

I have an operation manual from ArtekMedia for the 5065A but it shows
the older OCXO and has no service details or schematic. Is a more
complete manual available anywhere?

Larry

On 12/2/2021 2:49 PM, Magnus Danielson via time-nuts wrote:

Hi Jared,

One of my 5065's have exactly this fault.

One approach is to rebuild with a new power inverter. Another is to
rebuild the amplifier board so it does not need -20 V and can operate
only on +20 V.

There should be DC-DC inverters, but I failed to grab a suitable
pre-built board for it.

I would enjoy not having to hear the 3.5 kHz switching frequency in my lab.

Cheers,
Magnus

...

Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

Try as I might, I cannot hear a single thing from my 5065A, which has run 24/7 for five years without issue. Jared earlier said he has inverter noise from his 5065A and now Magnus reports it also. How common is this? I will be interested in a replacement A15 regulator board as Ulf Kylenfall SM6GXV described. Let's allow Ulf to build and test the PWBs he receives and then some kind of group buy could be arranged. I have an operation manual from ArtekMedia for the 5065A but it shows the older OCXO and has no service details or schematic. Is a more complete manual available anywhere? Larry On 12/2/2021 2:49 PM, Magnus Danielson via time-nuts wrote: > Hi Jared, > > One of my 5065's have exactly this fault. > > One approach is to rebuild with a new power inverter. Another is to > rebuild the amplifier board so it does not need -20 V and can operate > only on +20 V. > > There should be DC-DC inverters, but I failed to grab a suitable > pre-built board for it. > > I would enjoy not having to hear the 3.5 kHz switching frequency in my lab. > > Cheers, > Magnus ... -- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland)

time-nuts@lists.febo.com

HP 5065A, no 2nd harmonic.

...