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Hi, Thanks for letting me join your group,? I have a HP3580A which I am going around in circles trying to repair. It has a large amplitude spurious signal at around 90hz (only around 10db lower than the Cal signal amplitude), this signal, depending on settings makes the unit unusable below around 300hz. The unit does work normally other than this signal. If you short (with a cap) the input to the A9U2 mixer it makes no difference to the spurious signal, but if you bypass the LO input to that mixer the signal drops significantly. This makes me think that this spurious signal may be riding on the LO signal,? but the LO signal at A9 TP4 looks exactly like the manual shows. You can reduce the amplitude of the spurious signal with the mixer balance trim pot, but this adjustment is extremely touchy, much more so than the adjustment would be in normal circumstances.?
I have found a few faulty electrolytic capacitors and replaced them, and in sheer desperation replaced many more capacitors. If anyone has any ideas it would be greatly appreciated? Thanks Steve
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Is the spur exactly 90 HZ? ?That might be a clue.
I would double check the mixer trim pot connections with an ohm meter on low range and also reflow the solder of joints.
You might need another 3580 to find the spur. ? :-(
--
Regards, Bernie Murphy
|
Hi Bernie
I have only been able to estimate the 90Hz signal by injecting a signal into the input from a sig gen at a high amplitude to override the spurious signal and see where it sits on the waveform. I actually suspect that the spurious signal is nothing like 90Hz but a signal close to the LO signal or a harmonic of it. Regarding the mixer, I have replaced the IC and the balance trim pot to no effect. I totally agree that the best way to fix it may be another 3850. I have for some time been on the lookout for a HP8556 plug in for my HP141T that would solve all the problems. Thank you for your suggestions? Steve Dench
Is the spur exactly 90 HZ?? That might be a clue.
I would double check the mixer trim pot connections with an ohm meter on low range and also reflow the solder of joints.
You might need another 3580 to find the spur. ? :-(
--
Regards, Bernie Murphy
|
There are several HP 8556s on E-bay
Cheers!
Bruce
Quoting Steve Dench <sjdench48@...>:
toggle quoted message
Show quoted text
Hi Bernie
I have only been able to estimate the 90Hz signal by injecting a signal
into the input from a sig gen at a high amplitude to override the spurious
signal and see where it sits on the waveform. I actually suspect that the
spurious signal is nothing like 90Hz but a signal close to the LO signal or
a harmonic of it.
Regarding the mixer, I have replaced the IC and the balance trim pot to no
effect.
I totally agree that the best way to fix it may be another 3850. I have for
some time been on the lookout for a HP8556 plug in for my HP141T that would
solve all the problems.
Thank you for your suggestions
Steve Dench
On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...> wrote:
Is the spur exactly 90 HZ? That might be a clue.
I would double check the mixer trim pot connections with an ohm meter on
low range and also reflow the solder of joints.
You might need another 3580 to find the spur. :-(
--
Regards, Bernie Murphy
|
Hi Bruce,? When I do an Ebay search it only shows one, that comes with 3 other units, while the price for the 4 items isnt bad, the postage to me in Australia for such a heavy package (of the 4 plugins) is way out of my budget. Its possible that other 8556s that are listed do not show up for me as they problably dont have international postage. (just a guess). Thanks for your reply. Steve.
On Thu, 8 Oct 2020, 1:28 pm Bruce, < bruce@...> wrote: There are several HP 8556s on E-bay
Cheers!
Bruce
Quoting Steve Dench <sjdench48@...>:
> Hi Bernie
>
> I have only been able to estimate the 90Hz signal by injecting a signal
> into the input from a sig gen at a high amplitude to override the spurious
> signal and see where it sits on the waveform. I actually suspect that the
> spurious signal is nothing like 90Hz but a signal close to the LO signal or
> a harmonic of it.
> Regarding the mixer, I have replaced the IC and the balance trim pot to no
> effect.
> I totally agree that the best way to fix it may be another 3850. I have for
> some time been on the lookout for a HP8556 plug in for my HP141T that would
> solve all the problems.
> Thank you for your suggestions
> Steve Dench
>
> On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...> wrote:
>
>> Is the spur exactly 90 HZ?? That might be a clue.
>>
>> I would double check the mixer trim pot connections with an ohm meter on
>> low range and also reflow the solder of joints.
>>
>> You might need another 3580 to find the spur.? ?:-(
>>
>> --
>> Regards, Bernie Murphy
>>
>>
>
>
>
|
Steve let me look. I could buy it and ship it to you. One thing I learned from using the 141/8555 series is it is a nice feature to have an IF for each "RF" unit - avoids wer and tear on the mating connectors and eliminates re-calibration each time.
Cheer!
Bruce
Quoting Steve Dench <sjdench48@...>:
toggle quoted message
Show quoted text
Hi Bruce,
When I do an Ebay search it only shows one, that comes with 3 other units,
while the price for the 4 items isnt bad, the postage to me in Australia
for such a heavy package (of the 4 plugins) is way out of my budget. Its
possible that other 8556s that are listed do not show up for me as they
problably dont have international postage. (just a guess).
Thanks for your reply. Steve.
On Thu, 8 Oct 2020, 1:28 pm Bruce, <bruce@...> wrote:
There are several HP 8556s on E-bay
Cheers!
Bruce
Quoting Steve Dench <sjdench48@...>:
Hi Bernie
I have only been able to estimate the 90Hz signal by injecting a signal
into the input from a sig gen at a high amplitude to override the spurious
signal and see where it sits on the waveform. I actually suspect that the
spurious signal is nothing like 90Hz but a signal close to the LO signal or
a harmonic of it.
Regarding the mixer, I have replaced the IC and the balance trim pot to no
effect.
I totally agree that the best way to fix it may be another 3850. I have for
some time been on the lookout for a HP8556 plug in for my HP141T that would
solve all the problems.
Thank you for your suggestions
Steve Dench
On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...> wrote:
Is the spur exactly 90 HZ? That might be a clue.
I would double check the mixer trim pot connections with an ohm meter on
low range and also reflow the solder of joints.
You might need another 3580 to find the spur. :-(
--
Regards, Bernie Murphy
|
I have a ¡®second LO and YIG¡¯ assy from an HP8559 SA which I just uncovered from a clear out... must have had it for years....
If there is any interest I will part with it for a reasonable offer...
Note: I am in UK
Unit is unknown condition electrically as I have no means of testing it.
Mechanically it looks good.
Can¡¯t recall why i kept it as I don¡¯t have a comparable analyser now...
Will post some images when I am back at home...
Just wondering if any parts are common to any other generator or analyser...
Would prefer to find a good home for it than recycle...
Regards
toggle quoted message
Show quoted text
On 8 Oct 2020, at 20:25, Bruce <bruce@...> wrote:
?Steve let me look. I could buy it and ship it to you. One thing I learned from using the 141/8555 series is it is a nice feature to have an IF for each "RF" unit - avoids wer and tear on the mating connectors and eliminates re-calibration each time.
Cheer!
Bruce
Quoting Steve Dench <sjdench48@...>:
Hi Bruce,
When I do an Ebay search it only shows one, that comes with 3 other units,
while the price for the 4 items isnt bad, the postage to me in Australia
for such a heavy package (of the 4 plugins) is way out of my budget. Its
possible that other 8556s that are listed do not show up for me as they
problably dont have international postage. (just a guess).
Thanks for your reply. Steve.
On Thu, 8 Oct 2020, 1:28 pm Bruce, <bruce@...> wrote:
There are several HP 8556s on E-bay
Cheers!
Bruce
Quoting Steve Dench <sjdench48@...>:
Hi Bernie
I have only been able to estimate the 90Hz signal by injecting a signal
into the input from a sig gen at a high amplitude to override the spurious
signal and see where it sits on the waveform. I actually suspect that the
spurious signal is nothing like 90Hz but a signal close to the LO signal or
a harmonic of it.
Regarding the mixer, I have replaced the IC and the balance trim pot to no
effect.
I totally agree that the best way to fix it may be another 3850. I have for
some time been on the lookout for a HP8556 plug in for my HP141T that would
solve all the problems.
Thank you for your suggestions
Steve Dench
On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...> wrote:
Is the spur exactly 90 HZ? That might be a clue.
I would double check the mixer trim pot connections with an ohm meter on
low range and also reflow the solder of joints.
You might need another 3580 to find the spur. :-(
--
Regards, Bernie Murphy
|
Hi Bruce, that is a very kind offer, but I do feel that the international postage for such heavy items will still be very high?? I do take your point on separate IF units, that does make perfect sense and I hadn't thought of that. Cheers Steve.
On Fri, 9 Oct 2020, 6:25 am Bruce, < bruce@...> wrote: Steve let me look.? I could buy it and ship it to you.? One thing I?
learned from using the 141/8555 series is it is a nice feature to have?
an IF for each "RF" unit - avoids wer and tear on the mating?
connectors and eliminates re-calibration each time.
Cheer!
Bruce
Quoting Steve Dench <sjdench48@...>:
> Hi Bruce,
> When I do an Ebay search it only shows one, that comes with 3 other units,
> while the price for the 4 items isnt bad, the postage to me in Australia
> for such a heavy package (of the 4 plugins) is way out of my budget. Its
> possible that other 8556s that are listed do not show up for me as they
> problably dont have international postage. (just a guess).
> Thanks for your reply. Steve.
>
> On Thu, 8 Oct 2020, 1:28 pm Bruce, <bruce@...> wrote:
>
>> There are several HP 8556s on E-bay
>>
>> Cheers!
>>
>> Bruce
>>
>> Quoting Steve Dench <sjdench48@...>:
>>
>> > Hi Bernie
>> >
>> > I have only been able to estimate the 90Hz signal by injecting a signal
>> > into the input from a sig gen at a high amplitude to override the
>> spurious
>> > signal and see where it sits on the waveform. I actually suspect that the
>> > spurious signal is nothing like 90Hz but a signal close to the LO signal
>> or
>> > a harmonic of it.
>> > Regarding the mixer, I have replaced the IC and the balance trim pot to
>> no
>> > effect.
>> > I totally agree that the best way to fix it may be another 3850. I have
>> for
>> > some time been on the lookout for a HP8556 plug in for my HP141T that
>> would
>> > solve all the problems.
>> > Thank you for your suggestions
>> > Steve Dench
>> >
>> > On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...>
>> wrote:
>> >
>> >> Is the spur exactly 90 HZ?? That might be a clue.
>> >>
>> >> I would double check the mixer trim pot connections with an ohm meter on
>> >> low range and also reflow the solder of joints.
>> >>
>> >> You might need another 3580 to find the spur.? ?:-(
>> >>
>> >> --
>> >> Regards, Bernie Murphy
>> >>
>> >>
>> >
>> >
>> >
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
|
Hi Nigel, thanks for the offer but I don't think that parts from an 8559 being a Ghz capable SA would be compatible with either the 3580A (50Khz) or a 8556A plugin which I would like to buy, but I do appreciate you thinking of me, maybe someone else on the forum could make use of them?? Cheers Steve.
On Fri, 9 Oct 2020, 6:54 am nigel adams via , <bristol.rell6l= [email protected]> wrote: I have a ¡®second LO and YIG¡¯ assy from an HP8559 SA which I just uncovered from a clear out... must have had it for years....
If there is any interest I will part with it for a reasonable offer...
Note: I am in UK
Unit is unknown condition electrically as I have no means of testing it.
Mechanically it looks good.
Can¡¯t recall why i kept it as I don¡¯t have a comparable analyser now...
Will post some images when I am back at home...
Just wondering if any parts are common to any other generator or analyser...
Would prefer to find a good home for it than recycle...
Regards
> On 8 Oct 2020, at 20:25, Bruce <bruce@...> wrote:
>
> ?Steve let me look.? I could buy it and ship it to you.? One thing I learned from using the 141/8555 series is it is a nice feature to have an IF for each "RF" unit - avoids wer and tear on the mating connectors and eliminates re-calibration each time.
>
> Cheer!
> Bruce
>
>
> Quoting Steve Dench <sjdench48@...>:
>
>> Hi Bruce,
>> When I do an Ebay search it only shows one, that comes with 3 other units,
>> while the price for the 4 items isnt bad, the postage to me in Australia
>> for such a heavy package (of the 4 plugins) is way out of my budget. Its
>> possible that other 8556s that are listed do not show up for me as they
>> problably dont have international postage. (just a guess).
>> Thanks for your reply. Steve.
>>
>>> On Thu, 8 Oct 2020, 1:28 pm Bruce, <bruce@...> wrote:
>>>
>>> There are several HP 8556s on E-bay
>>>
>>> Cheers!
>>>
>>> Bruce
>>>
>>> Quoting Steve Dench <sjdench48@...>:
>>>
>>> > Hi Bernie
>>> >
>>> > I have only been able to estimate the 90Hz signal by injecting a signal
>>> > into the input from a sig gen at a high amplitude to override the
>>> spurious
>>> > signal and see where it sits on the waveform. I actually suspect that the
>>> > spurious signal is nothing like 90Hz but a signal close to the LO signal
>>> or
>>> > a harmonic of it.
>>> > Regarding the mixer, I have replaced the IC and the balance trim pot to
>>> no
>>> > effect.
>>> > I totally agree that the best way to fix it may be another 3850. I have
>>> for
>>> > some time been on the lookout for a HP8556 plug in for my HP141T that
>>> would
>>> > solve all the problems.
>>> > Thank you for your suggestions
>>> > Steve Dench
>>> >
>>> > On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...>
>>> wrote:
>>> >
>>> >> Is the spur exactly 90 HZ?? That might be a clue.
>>> >>
>>> >> I would double check the mixer trim pot connections with an ohm meter on
>>> >> low range and also reflow the solder of joints.
>>> >>
>>> >> You might need another 3580 to find the spur.? ?:-(
>>> >>
>>> >> --
>>> >> Regards, Bernie Murphy
>>> >>
>>> >>
>>> >
>>> >
>>> >
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>
>
>
>
>
>
>
>
|
No problem - If you ever need someone to do something like this, I'm generally happy to do so - if you wanted something savaged for particular parts, I'd also consider that - depending on the size and scope.
Cheers!
Quoting Steve Dench <sjdench48@...>:
toggle quoted message
Show quoted text
Hi Bruce, that is a very kind offer, but I do feel that the international
postage for such heavy items will still be very high? I do take your point
on separate IF units, that does make perfect sense and I hadn't thought of
that.
Cheers Steve.
On Fri, 9 Oct 2020, 6:25 am Bruce, <bruce@...> wrote:
Steve let me look. I could buy it and ship it to you. One thing I
learned from using the 141/8555 series is it is a nice feature to have
an IF for each "RF" unit - avoids wer and tear on the mating
connectors and eliminates re-calibration each time.
Cheer!
Bruce
Quoting Steve Dench <sjdench48@...>:
Hi Bruce,
When I do an Ebay search it only shows one, that comes with 3 other units,
while the price for the 4 items isnt bad, the postage to me in Australia
for such a heavy package (of the 4 plugins) is way out of my budget. Its
possible that other 8556s that are listed do not show up for me as they
problably dont have international postage. (just a guess).
Thanks for your reply. Steve.
On Thu, 8 Oct 2020, 1:28 pm Bruce, <bruce@...> wrote:
There are several HP 8556s on E-bay
Cheers!
Bruce
Quoting Steve Dench <sjdench48@...>:
Hi Bernie
I have only been able to estimate the 90Hz signal by injecting a signal
into the input from a sig gen at a high amplitude to override the spurious
signal and see where it sits on the waveform. I actually suspect that
the
spurious signal is nothing like 90Hz but a signal close to the LO
signal
or
a harmonic of it.
Regarding the mixer, I have replaced the IC and the balance trim pot
to
no
effect.
I totally agree that the best way to fix it may be another 3850. I
have
for
some time been on the lookout for a HP8556 plug in for my HP141T that would
solve all the problems.
Thank you for your suggestions
Steve Dench
On Thu, 8 Oct 2020, 11:07 am Ham Radio, <bernard.murphy@...> wrote:
Is the spur exactly 90 HZ? That might be a clue.
I would double check the mixer trim pot connections with an ohm
meter on
low range and also reflow the solder of joints.
You might need another 3580 to find the spur. :-(
--
Regards, Bernie Murphy
|
