Wow you guys are fast to help!
Here is some more info: error is only from 20-40GHz, so it has something to do with the doubler I assume. Any span or frequency in this range has this error. I have seen >20GHz work for a little while but only randomly. My next idea is a shorter DB25 cable as mine is about 20 feet long. Tried turning up the LO power coming in on the sweeper with no luck. I can't find a replacement doubler on ebay to test with. These must be very rare. Can they be serviced? This display/sweeper/control box setup has been tested with an 8515 and no errors at all.
|
Re: Spectrum analyzer in a high traffic strong signal environment
Hi:
You might switch in some attenuation and see if all the peaks fall by that amount.
--
Have Fun,
Brooke Clarke, N6GCE
axioms:
1. The extent to which you can fix or improve something will be limited by how well you understand how it works.
2. Everybody, with no exceptions, holds false beliefs.
|
Agreed you have to excersize caution when working on the test set especially if it comes to 2.4mm connectors and hardlines
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: Bruce via groups.io
Sent: Wednesday, March 2, 2022 4:32 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
Absolutely agree, but it can be problematic to dig into the test set?
if the problem is in the 85202.? The test set is more easilly damaged,?
particularly if you are unfamiliar with its innards.
The other thing he should confirm is the 834X OUTPUT at the test set input.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
> True but in all the years I been fixing those units back at tucker?
> about 85% of all failures were testset related
>
> Sent from Mail<> for Windows
>
> From: Bruce via groups.io<mailto:bruce@...>
> Sent: Wednesday, March 2, 2022 4:24 PM
> To:?
> [email protected]<mailto:[email protected]>
> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>
> Note that the problem could also be in the 85102 IF unit.? Do you have
> either the test set simulator or a second test set of some kind?
>
> The test set simulator is a plug that fits the IF RF outputs and has a
> connector for the 20.4MHz signal from the IF to provide a signal
> approximating the outputs from the test set.
>
> It would be bet to confirm the 85102 before digging nto the 8516.
>
> Cheers!
>
> Bruce
>
> Quoting Lothar baier <Lothar@...>:
>
>> Ok so the 8510 test-sets have 4 samplers , 2 of them are connected
>> to the couplers , the other 2 are reference samplers , those are
>> connected to the switch/splitter , the RF coming in from the source
>> is split inside of this assembly in 3 paths , 2 reference paths that
>> are connected to the reference samplers the third one is routed to a
>> switch which switches the RF either to coupler 1 or 2 while
>> terminating the unused coupler in 50ohm !
>> NO IF FOUND usually indicates that either one or both reference
>> samplers does not receive a signal or that the signal level is to
>> low .
>> This can have multiple reasons :
>>
>>?? 1.? The Source output level is to low , cable from source to the
>> testset might be broke
>>?? 2.? Doubler amplifier assembly is bad
>>?? 3.? Switch /Splitter bad
>>?? 4.? Bad sampler or sampler driver
>> Note that for 2 or 3 defective can also mean issues with the control
>> circuits !
>> You can also get this error if you have power holes in the source
>>
>> First thing to do is to set the start and stop frequency to a small
>> range like 2-4GHz or 1-2GHz and see if the error goes away, if it
>> does then increase the sweep range to see where the error starts to
>> appear !
>> Next check the source level at the end of the cable you use to
>> connect the source to the test-set , make sure the level is within
>> the range the test-set can process
>> If this doesn’t resolve things take the lid of the test-set and
>> check your DC Voltages to ensure they are all correct , next
>> disconnect the output of the doubler amplifier block and check if
>> you have RF coming out ,? you can also connect the source directly
>> to the cable that connects the doubler to the switch splitter set
>> your sweep from 2-10GHz if the error goes away you have a problem
>> with the doubler or doubler control if its still present you have to
>> check the signal at your samplers if the signal is there your
>> sampler is bad or the sampler driver
>>
>> Sent from Mail<> for Windows
>>
>> From: ratn9ne via groups.io<mailto:ratn9ne@...>
>> Sent: Wednesday, March 2, 2022 2:37 PM
>> To:
>> [email protected]<mailto:[email protected]>
>> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>>
>> I have a complete 8516 VNA setup and it was intermittently working
>> with a standard DB25 Thru cable. Right now I am stuck on "NO IF
>> FOUND" error and out of ideas.
>>
>>
>>
>>
>>
>
>
>
>
>
>
>
>
>
>
>
?
|
Absolutely agree, but it can be problematic to dig into the test set if the problem is in the 85202. The test set is more easilly damaged, particularly if you are unfamiliar with its innards.
The other thing he should confirm is the 834X OUTPUT at the test set input.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
True but in all the years I been fixing those units back at tucker about 85% of all failures were testset related
Sent from Mail<> for Windows
From: Bruce via groups.io<mailto:bruce@...>
Sent: Wednesday, March 2, 2022 4:24 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
Note that the problem could also be in the 85102 IF unit. Do you have
either the test set simulator or a second test set of some kind?
The test set simulator is a plug that fits the IF RF outputs and has a
connector for the 20.4MHz signal from the IF to provide a signal
approximating the outputs from the test set.
It would be bet to confirm the 85102 before digging nto the 8516.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Ok so the 8510 test-sets have 4 samplers , 2 of them are connected
to the couplers , the other 2 are reference samplers , those are
connected to the switch/splitter , the RF coming in from the source
is split inside of this assembly in 3 paths , 2 reference paths that
are connected to the reference samplers the third one is routed to a
switch which switches the RF either to coupler 1 or 2 while
terminating the unused coupler in 50ohm !
NO IF FOUND usually indicates that either one or both reference
samplers does not receive a signal or that the signal level is to
low .
This can have multiple reasons :
1. The Source output level is to low , cable from source to the
testset might be broke
2. Doubler amplifier assembly is bad
3. Switch /Splitter bad
4. Bad sampler or sampler driver
Note that for 2 or 3 defective can also mean issues with the control
circuits !
You can also get this error if you have power holes in the source
First thing to do is to set the start and stop frequency to a small
range like 2-4GHz or 1-2GHz and see if the error goes away, if it
does then increase the sweep range to see where the error starts to
appear !
Next check the source level at the end of the cable you use to
connect the source to the test-set , make sure the level is within
the range the test-set can process
If this doesn’t resolve things take the lid of the test-set and
check your DC Voltages to ensure they are all correct , next
disconnect the output of the doubler amplifier block and check if
you have RF coming out , you can also connect the source directly
to the cable that connects the doubler to the switch splitter set
your sweep from 2-10GHz if the error goes away you have a problem
with the doubler or doubler control if its still present you have to
check the signal at your samplers if the signal is there your
sampler is bad or the sampler driver
Sent from Mail<> for Windows
From: ratn9ne via groups.io<mailto:ratn9ne@...>
Sent: Wednesday, March 2, 2022 2:37 PM
To:
[email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
I have a complete 8516 VNA setup and it was intermittently working
with a standard DB25 Thru cable. Right now I am stuck on "NO IF
FOUND" error and out of ideas.
|
True but in all the years I been fixing those units back at tucker about 85% of all failures were testset related
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: Bruce via groups.io
Sent: Wednesday, March 2, 2022 4:24 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
Note that the problem could also be in the 85102 IF unit.? Do you have?
either the test set simulator or a second test set of some kind?
The test set simulator is a plug that fits the IF RF outputs and has a?
connector for the 20.4MHz signal from the IF to provide a signal?
approximating the outputs from the test set.
It would be bet to confirm the 85102 before digging nto the 8516.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
> Ok so the 8510 test-sets have 4 samplers , 2 of them are connected?
> to the couplers , the other 2 are reference samplers , those are?
> connected to the switch/splitter , the RF coming in from the source?
> is split inside of this assembly in 3 paths , 2 reference paths that?
> are connected to the reference samplers the third one is routed to a?
> switch which switches the RF either to coupler 1 or 2 while?
> terminating the unused coupler in 50ohm !
> NO IF FOUND usually indicates that either one or both reference?
> samplers does not receive a signal or that the signal level is to?
> low .
> This can have multiple reasons :
>
>?? 1.? The Source output level is to low , cable from source to the?
> testset might be broke
>?? 2.? Doubler amplifier assembly is bad
>?? 3.? Switch /Splitter bad
>?? 4.? Bad sampler or sampler driver
> Note that for 2 or 3 defective can also mean issues with the control?
> circuits !
> You can also get this error if you have power holes in the source
>
> First thing to do is to set the start and stop frequency to a small?
> range like 2-4GHz or 1-2GHz and see if the error goes away, if it?
> does then increase the sweep range to see where the error starts to?
> appear !
> Next check the source level at the end of the cable you use to?
> connect the source to the test-set , make sure the level is within?
> the range the test-set can process
> If this doesn’t resolve things take the lid of the test-set and?
> check your DC Voltages to ensure they are all correct , next?
> disconnect the output of the doubler amplifier block and check if?
> you have RF coming out ,? you can also connect the source directly?
> to the cable that connects the doubler to the switch splitter set?
> your sweep from 2-10GHz if the error goes away you have a problem?
> with the doubler or doubler control if its still present you have to?
> check the signal at your samplers if the signal is there your?
> sampler is bad or the sampler driver
>
> Sent from Mail<> for Windows
>
> From: ratn9ne via groups.io<mailto:ratn9ne@...>
> Sent: Wednesday, March 2, 2022 2:37 PM
> To:?
> [email protected]<mailto:[email protected]>
> Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
>
> I have a complete 8516 VNA setup and it was intermittently working?
> with a standard DB25 Thru cable. Right now I am stuck on "NO IF?
> FOUND" error and out of ideas.
>
>
>
>
>
?
|
Note that the problem could also be in the 85102 IF unit. Do you have either the test set simulator or a second test set of some kind?
The test set simulator is a plug that fits the IF RF outputs and has a connector for the 20.4MHz signal from the IF to provide a signal approximating the outputs from the test set.
It would be bet to confirm the 85102 before digging nto the 8516.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
toggle quoted message
Show quoted text
Ok so the 8510 test-sets have 4 samplers , 2 of them are connected to the couplers , the other 2 are reference samplers , those are connected to the switch/splitter , the RF coming in from the source is split inside of this assembly in 3 paths , 2 reference paths that are connected to the reference samplers the third one is routed to a switch which switches the RF either to coupler 1 or 2 while terminating the unused coupler in 50ohm !
NO IF FOUND usually indicates that either one or both reference samplers does not receive a signal or that the signal level is to low .
This can have multiple reasons :
1. The Source output level is to low , cable from source to the testset might be broke
2. Doubler amplifier assembly is bad
3. Switch /Splitter bad
4. Bad sampler or sampler driver
Note that for 2 or 3 defective can also mean issues with the control circuits !
You can also get this error if you have power holes in the source
First thing to do is to set the start and stop frequency to a small range like 2-4GHz or 1-2GHz and see if the error goes away, if it does then increase the sweep range to see where the error starts to appear !
Next check the source level at the end of the cable you use to connect the source to the test-set , make sure the level is within the range the test-set can process
If this doesn’t resolve things take the lid of the test-set and check your DC Voltages to ensure they are all correct , next disconnect the output of the doubler amplifier block and check if you have RF coming out , you can also connect the source directly to the cable that connects the doubler to the switch splitter set your sweep from 2-10GHz if the error goes away you have a problem with the doubler or doubler control if its still present you have to check the signal at your samplers if the signal is there your sampler is bad or the sampler driver
Sent from Mail<> for Windows
From: ratn9ne via groups.io<mailto:ratn9ne@...>
Sent: Wednesday, March 2, 2022 2:37 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
I have a complete 8516 VNA setup and it was intermittently working with a standard DB25 Thru cable. Right now I am stuck on "NO IF FOUND" error and out of ideas.
|
Ok so the 8510 test-sets have 4 samplers , 2 of them are connected to the couplers , the other 2 are reference samplers , those are connected to the switch/splitter , the RF coming in from the source is split inside of this assembly in
3 paths , 2 reference paths that are connected to the reference samplers the third one is routed to a switch which switches the RF either to coupler 1 or 2 while terminating the unused coupler in 50ohm !
NO IF FOUND usually indicates that either one or both reference samplers does not receive a signal or that the signal level is to low .
This can have multiple reasons :
- The Source output level is to low , cable from source to the testset might be broke
- Doubler amplifier assembly is bad
- Switch /Splitter bad
- Bad sampler or sampler driver
Note that for 2 or 3 defective can also mean issues with the control circuits !
You can also get this error if you have power holes in the source
?
First thing to do is to set the start and stop frequency to a small range like 2-4GHz or 1-2GHz and see if the error goes away, if it does then increase the sweep range to see where the error starts to appear !
Next check the source level at the end of the cable you use to connect the source to the test-set , make sure the level is within the range the test-set can process
If this doesn’t resolve things take the lid of the test-set and check your DC Voltages to ensure they are all correct , next disconnect the output of the doubler amplifier block and check if you have RF coming out ,? you can also connect
the source directly to the cable that connects the doubler to the switch splitter set your sweep from 2-10GHz if the error goes away you have a problem with the doubler or doubler control if its still present you have to check the signal at your samplers if
the signal is there your sampler is bad or the sampler driver
?
Sent from for Windows
?
toggle quoted message
Show quoted text
From: ratn9ne via groups.io
Sent: Wednesday, March 2, 2022 2:37 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] 8516A cable question
?
I have a complete 8516 VNA setup and it was intermittently working with a standard DB25 Thru cable. Right now I am stuck on "NO IF FOUND" error and out of ideas.
|
Re: Spectrum analyzer in a high traffic strong signal environment
Another measure is to look at the level of the LO feed through at "0" frequency. Usually expected to be less than -20 dB (that is what I see on 8566 SA)
Cheers!
Bruce
Quoting nj902 <wb0emu@...>:
toggle quoted message
Show quoted text
If the analyzer shows the correct level from the calibrator - it's probably fine.? If your instrument requires you to connect a jumper between the calibrator output and the RF input - that is an even higher confidence.
For a more comprehensive verification, connect your signal generator to the spectrum analyzer and measure various frequencies and amplitudes.
When measuring signals in a high RF environment, if you suspect mixer overload, increase the input attenuation.? If the suspect signals decrease by more that the extra attenuation, they were bogus.
Also, most analyzers won't reduce attenuation below 10 dB without extra steps.? That protects the instrument because attenuators aren't as easy to damage (or as expensive) as mixers are.? Zero dB attenuation can give you the most sensitivity for viewing weak signals - but - don't go there unless you are sure it is safe.
|
Re: Spectrum analyzer in a high traffic strong signal environment
If the analyzer shows the correct level from the calibrator - it's probably fine.? If your instrument requires you to connect a jumper between the calibrator output and the RF input - that is an even higher confidence.
For a more comprehensive verification, connect your signal generator to the spectrum analyzer and measure various frequencies and amplitudes.
When measuring signals in a high RF environment, if you suspect mixer overload, increase the input attenuation.? If the suspect signals decrease by more that the extra attenuation, they were bogus.
Also, most analyzers won't reduce attenuation below 10 dB without extra steps.? That protects the instrument because attenuators aren't as easy to damage (or as expensive) as mixers are.? Zero dB attenuation can give you the most sensitivity for viewing weak signals - but - don't go there unless you are sure it is safe.
|
Re: Spectrum analyzer in a high traffic strong signal environment
Thanks,
I have to confess this happened to me recently with a spectrum analyzer. Currently it seems to work fine where the -10dB calibrator shows -10dB on the display.
Is there ways which I might assess the health of the input to the spectrum analyzer if I might have actually hurt something? Thanks
Ops!
|
I have a complete 8516 VNA setup and it was intermittently working with a standard DB25 Thru cable. Right now I am stuck on "NO IF FOUND" error and out of ideas.
|
Re: 334A Distortion Analyzer, etc.
My quick knee-jerk without studying the schematic is, if it’s in the signal chain, you probably want a high-gain low-noise part like a BC556.? If you only have a 2N3906, it would be okay for debug.
?
Dave Wise
?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]>
On Behalf Of Colin Herbert via groups.io
Sent: Wednesday, March 02, 2022 11:10 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] 334A Distortion Analyzer, etc.
?
Hi All,
I have been puzzling for a while but I'm not sure that I have got to the truth yet.
I have a H-P 334A Distortion Analyzer which I put away a while ago and now I find that something is not right. When I turn the instrument on, the meter-needle swings to the right and then comes back to zero fairly quickly. Unfortunately, there is still a little
movement on the meter-needle but this settles down eventually. Since it looks as though the current isn't passing completely down the A2R44, A2Q8 and A2Q9 components completely, I have ascertained that transistor A2Q9 has probably died on me. This transistor
was originally a Motorola SM4713 PNP silicon type. Research tell me that while this transistor is discontinued, an equivalent is probably a 2N3251. However, this is a bit pricey just to check out and I suspect that a?2N3906
will probably suffice just to check. Has anyone else any better ideas? I really want to get this Distortion Analyser working satisfactorily. Thanks is anticipation,
Colin.
|
334A Distortion Analyzer, etc.
Hi All,
I have been puzzling for a while but I'm not sure that I have got to the truth yet.
I have a H-P 334A Distortion Analyzer which I put away a while ago and now I find that something is not right. When I turn the instrument on, the meter-needle swings to the right and then comes back to zero fairly quickly. Unfortunately, there is still a little movement on the meter-needle but this settles down eventually. Since it looks as though the current isn't passing completely down the A2R44, A2Q8 and A2Q9 components completely, I have ascertained that transistor A2Q9 has probably died on me. This transistor was originally a Motorola SM4713 PNP silicon type. Research tell me that while this transistor is discontinued, an equivalent is probably a 2N3251. However, this is a bit pricey just to check out and I suspect that a?2N3906 will probably suffice just to check. Has anyone else any better ideas? I really want to get this Distortion Analyser working satisfactorily. Thanks is anticipation,
Colin.
|
Re: Spectrum analyzer in a high traffic strong signal environment
"...is it possible that although the input levels look fine on screen when in reality the analyzer is actually seeing higher than -30dB at it's input..."
-
Not only is it possible, it is very probable.? Before connecting a spectrum analyzer to any antenna, I like to connect the antenna to an RF power meter.? The broadband sensor will measure the total RF energy that will be incident on your spectrum analyzer's mixer.
In most cases, I believe it is necessary to use some sort of preselector to narrow the spectrum to the area of interest.? I have a complete set of K&L tunable preselectors covering the range from 80 MHz to 1 GHz.? Each covers an octave band.
|
Re: Spectrum analyzer in a high traffic strong signal environment
If the signals are radiated then using cables and adapters with very good shielding can help mitigate the issues but if they are conducted than things become difficult!
toggle quoted message
Show quoted text
On Mar 2, 2022, at 11:23, DW via groups.io <wilson2115@...> wrote:
?There might be cases where a spectrum analyzer is used to measure a particular signal that is surrounded by many adjacent strong signals. Perhaps the signal measured isn't as strong as the adjacent signals and requires and increase in level
but unfortunately the adjacent signals are raised as well.
Although none of the strong adjacent signals are overpowering of the analyzer, perhaps they are all somewhere around -30dBm but there are about 10 of them or more, is it possible that although the input levels look fine on screen when in reality the analyzer
is actually seeing higher than -30dB at it's input thus staying below the input level limits might not always be so obvious.
Thoughts on this, thanks
|
Spectrum analyzer in a high traffic strong signal environment
There might be cases where a spectrum analyzer is used to measure a particular signal that is surrounded by many adjacent strong signals. Perhaps the signal measured isn't as strong as the adjacent signals and requires and increase in level but unfortunately the adjacent signals are raised as well.
Although none of the strong adjacent signals are overpowering of the analyzer, perhaps they are all somewhere around -30dBm but there are about 10 of them or more, is it possible that although the input levels look fine on screen when in reality the analyzer is actually seeing higher than -30dB at it's input thus staying below the input level limits might not always be so obvious.
Thoughts on this, thanks
|
Re: HP8640B RF Fails Several Seconds After Power Up
My 8640B came with trashed RANGE and DEVIATION knobs.? Rather than hunt down spares, I cobbled my own.? I took a generic knob and simply attached the old skirt to it.? It looks
wrong but works right.
?
FWIW,
Dave Wise
?
toggle quoted message
Show quoted text
From: [email protected] <[email protected]>
On Behalf Of Brian via groups.io
Sent: Wednesday, March 02, 2022 2:21 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP8640B RF Fails Several Seconds After Power Up
?
Hello George, from 12,000 miles away.
?
If only I had met you when I lived and worked in the UK.
?
I have a couple of 8640Bs that I’ve managed to keep going – the odd capacitor failing, and those dreaded gears going U/S.
?
A member of the radio club asked me to look at an 8640B that wasn’t working. There was no RF output and gears were so badly cracked you couldn’t turn the knobs.
Someone must have tried because one of the wings on the band-change knob is missing. Now that I’ve replaced gears and lubricated bearings, the band change is fine. Unfortunately, even Walter of Sphere Research in Canada can’t help with that knob; can you?
?
I now have reliable RF output, but no frequency readout. I purchased another frequency readout module from a person scrapping an 8640B, who claimed his counter
had been working. But, in fact, neither counter works. Can you help?
?
73 de Brian, VK2GCE
?
?
Hi
I have repaired a number of HP8640B signal generators with similar faults, the TO3 sockets for the power supply pass transistors go faulty with time resulting in poor Base and Emitter connections.
G Edmonds G6HIG
|
Re: looking for HP 8340/41B Manual change supplement for 2804A and 2812A Serial# range
"Lothar baier" <Lothar@...> writes: Its the 8516A 40GHz testset !
The manual outlines that FW 11.88 is required and SN 2812A or higher.
Yes there are hardware changes, the CPU and sweep board have different part numbers , the 8516 uses a internal doubler to use a 20GHz source the doubler is controlled over a controll interface on the back of the testset which is connected to the 8410 interface connector on the 8340 , I assume that HP changed the CPU board to be able to control the 8516 and discard the 8410 controll.
I ordered a CPU board on ebay for $75 and will change it out to see if it works, if not i will also change the sweep board
On Mar 2, 2022, at 00:42, Matt Huszagh via groups.io <huszaghmatt@...> wrote: Interesting, thanks for sharing. I checked my own manuals. The one I purchased from Artek has the 2812A component level service manual for the 8340B, but only volume 2. The copy of volume 1 there is for prefix 2650A. However, I think vol 2 is the only one you need. This contains the backdating information. There's more than 20 pages describing the changes from the 2804A prefix, including changes to the A58 and A60 assemblies. Matt
|
Re: HP8640B RF Fails Several Seconds After Power Up
Hello George, from 12,000 miles away.
?
If only I had met you when I lived and worked in the UK.
?
I have a couple of 8640Bs that I’ve managed to keep going – the odd
capacitor failing, and those dreaded gears going U/S.
?
A member of the radio club asked me to look at an 8640B that
wasn’t working. There was no RF output and gears were so badly cracked you
couldn’t turn the knobs. Someone must have tried because one of the wings on
the band-change knob is missing. Now that I’ve replaced gears and lubricated
bearings, the band change is fine. Unfortunately, even Walter of Sphere
Research in Canada can’t help with that knob; can you?
?
I now have reliable RF output, but no frequency readout. I
purchased another frequency readout module from a person scrapping an 8640B,
who claimed his counter had been working. But, in fact, neither counter works.
Can you help?
?
73 de Brian, VK2GCE
?
?
Hi
I have repaired a number of HP8640B signal generators with
similar faults, the TO3 sockets for the power supply pass transistors go faulty
with time resulting in poor Base and Emitter connections.
G Edmonds G6HIG
|
Re: 8350B *restoration adventure?*
Hi Ruben, sorry, for white/white-red wire, the AC current for “no plugin” is 2.67A, not 267mA…I forgot to multiply by ten for this measurement, my probe was on the scale 100mV/A. ? ? Yves ? Yves, that data is very helpful, thank you so much! Helps a lot indeed ;)
Giving a first sight to your numbers, I noticed in AC current measurement, that my figures are similar to yours except for the white-white/red-white. I have the plugin connected draw figures without any plugin. So weird. Remember the old transformer was destroyed by melted and shorted secondarys. That said, I have the power for two hours last time and no hot heat sink or malfunction of the logic circuitry. The filter caps was tested OK. I bought new extrafine test probes, so next step is measure the DC current using fuse sockets.?
To be continued... ? PD Lothar, I always look for 'best offer' auctions on eBay, but the shipment and customs still very heavy. It's a disadvantage to live in Europe for this hobby :D
Regards,
Ruben
|
Willy
Brian