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Re: Help request - how to test an HP8350B RF plugin YIG

 

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Hi,

?

I have some experience with the 8350B, as I have three plug-ins including an 83595A that I have repaired with some difficulty.

?

There is the YIG OSC signal that is coupled and outputs on the rear panel AUX OUTPUT.

You measured there, and there was no RF signal present, so I would say that the YIG OSC is not working.

There is only a coupler between the YIG output and the AUX OUTPUT.

It would be necessary to confirm that the bias and all voltages to the YIG are correct.

?

For the A8 PCB that doesn't seem to work in the faulty plug-in, measure A8TP10 and A8TP6, both should have the same signal.

If TP6 has DC noise as you mentioned, then the circuit would not be able to correct the current flowing in the YIG coil, and thus the feedback loop would be open.

I would tend to think that there would be an error in the measurement (bad contact or something), since this same A8 board works in the other plug-in.

?

In my 83595A plug-in, the A8 board is an 83592-60002, we probably have the same A8 board.

So, I did a measurement at TP6 and TP10, and it is according to the service manual.

?

?

Yves

?

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De?: [email protected] <[email protected]> De la part de Paul Bicknell
·¡²Ô±¹´Ç²â¨¦?: 22 septembre 2024 21:12
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] Help request - how to test an HP8350B RF plugin YIG

?

OK going from memory the 83592A RF plug-in is actually a very compact unit with a lot to it

The yig signal should be available on the rear of the plug in so I would start there next try the output on the fundamental Yig frequency band

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I assume you have checked the 8350 with another plug in and all is OK as the stand by battery¡¯s are a killer for the 8350 when they age best advice is to remove the stand by battery¡¯s?

if they are in a sorry state? then the 8350 frame could suffer from bad joints and connections also the IDC will be at risk of intermittent faults ?I have recently scraped an A version it has repaired 8 other sweepers / plugins ?

I love these sweepers but faults can be tricky to sort out

Paul

?

?

From: [email protected] [mailto:[email protected]] On Behalf Of i.brokos via groups.io
Sent: 22 September 2024 22:20
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Help request - how to test an HP8350B RF plugin YIG

?

Hello,

I'm trying to repair a 83592A RF plug-in

I have bought it from eBay with many components missing, and I have completed it.

Furthermore, I have changed the 300uF cap on A8 board, it was in it.

?

I looked for a signal in the front output or the AUX output, NO RF power - All Bands.

?

From the manual, I have the troubleshooting procedure (see photo)

I have measured on A13AI YO BIAS PCB test points (See photo)

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YO Coil Current Source Waveforms in A8TP6 (see photo) is flat/noise !

With another A8 Board from a working plug-in, the YO Coil Current Source Waveforms in

A8TP6 is present, but again there is NO RF power - All Bands

?

I tried the working plug in with the A8 from the plug in I try to repair (not working plug in)

the YO Coil Current Source Waveforms in A8TP6 is present, and the plug in is working!!!!

That means that the two A8 boards are working !!

?

I can't understand why on the no working plug in the one A8 the YO Coil Current Source Waveforms in

A8TP6 is present and in the other doesn't when in the working plug in both A8 YO Coil Current Source Waveforms in

A8TP6 is present?

??

?

Furthermore, I can't measure TP "G"

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Can I disconnect the J2 without burning the YO (if it is working!) and take the measurement of TP "G" for -2Vdc?

OR it is not necessary the YO is failure ?

?

If there is any suggestion on the next steps, it will help

JOHN

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?

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Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on

 

One more thing you can do is to check the traces on the motherboard that connect the processor and memory boards. Maybe one of them is open or shorted.?
Thanks i'm gonna try that, i did not check that.
?
It seems from your posts that you are in the UK, AU, or NZ.
I'm actually from France, where those are even rarer. I've been looking at spectrum analysers online for more than a year and i never came across a 8568 (A or B).
?
Thx for the help again.
Re: HP 8566B Not Showing Any Signal

 

Here is a video of the 100MHz calibrated signal going into the input of the attenuator. Does this look correct?
Re: HP 8566B Not Showing Any Signal

 

New attenuators in use and unless I totally misunderstand how the 8566B is running things, that's not a constant step in attenuation.
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Thoughts?
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Re: 8665B noisy signal & Cal Errors

 

Hi Dave,?
?
Sorry, I was rushing to dinner earlier and missed part of your question. Settings on the SA (8566B) were 3 GHz center frequency, 2 MHz span, RBW 30 kHz, VBW 100 kHz, sweep 20 msec, 10 dBm attenuation.?
?
Settings on the 8665B sig gen were 3 Ghz, 0 dBm, modulation off.?
?
I later did a peak-hold to measure the average of the taller spurs, which flat topped with a bandwidth of about 10 kHz or so. Unfortunately I forgot to get a picture of that, and now the unit is partly disassembled awaiting parts.?
?
When you say "line triggered", do you mean a single sweep? As opposed to continuous? Yes, I did, and it looks exactly the same as if the video were paused.?

One thing I will say is they flutter in sync with each other. If the left spur goes down in frequency, so does the right spur. And likewise. The carrier never budges.?
Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on

 

Yes, having a spare parts box may not be a bad idea. Here in the U.S., the 8568A/B is almost unwanted. It seems from your posts that you are in the UK, AU, or NZ. It may be harder to find a cheap parts box there.
?
The 8568 is a really great analyzer. In fact, if you don't need to see above 1.5 GHz, it's more attractive than the 8566 because it barely has any microcircuits. Not to mention the extremely tedious front end alignment in the 8566.
?
One more thing you can do is to check the traces on the motherboard that connect the processor and memory boards. Maybe one of them is open or shorted.?
?
Vladan
Re: HP 141T Power Supply Help Needed

 

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/g/HP-Agilent-Keysight-equipment/photo/68333/805597

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From: [email protected] <[email protected]> On Behalf Of Michael Bafaro via groups.io
Sent: 23 September 2024 21:05
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

Dave,

?

How do I view ¡°141T reference replacement¡±?? Are there PCBs available? If so what is the price?

?

Mike

?

From: [email protected] <[email protected]> On Behalf Of Dave Wise
Sent: Monday, September 23, 2024 11:24 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

Already done, see ¡°141T reference?replacement" topic and photo album.

?

Dave Wise

From: [email protected] <[email protected]> on behalf of Michael Bafaro via groups.io <m.bafaro@...>
Sent: Monday, September 23, 2024 9:04 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

Bill,

?

The 141T that I purchased from Valuetronics now has a new fan and the power transistor sockets have been replaced. Now the 1A fuses on the 8552 IF module are popping.? I built a fixture that I can monitor the basic supply voltages with out the plugins in and the 141T covers on.? ?It turns out that there is an over voltage crowbar circuit in the IF module that fires at -15V.? I took some startup scope traces and they show that the -12.6V over shoots to -15.2V and the +100 overshoots as well.? Since these are tracking regulators and the basic reference is the neon tube in the +100V supply I tested it during startup and it overshoots badly.? Enclosed are some of the startup scope traces I took.? I am working on a circuit that will replace the neon tube with a 50V Zener in series with a TL431.? Since the 50V Zener will be inside the control loop its temp coefficient will not be an issue.? I will publish the TL431 design later in the week.?

?

Mike

?

From: [email protected] <[email protected]> On Behalf Of Bill Berzinskas
Sent: Friday, September 20, 2024 11:30 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

CONV mode is the only functional mode, i get blooming at almost any intensity / persistence setting in storage mode unless its so low its basically OFF.? ? ? ??

?

On Fri, Sep 20, 2024 at 12:21?PM factory via <bobradios11=[email protected]> wrote:

Beware of using the 141T in "Conv" mode, you cannot see if the intensity is set too high & causing damaging the storage mesh. You need to start with it in storage mode and turn intensity down to stop the blooming, then switch to "Conv", if there is any blooming, the intensity is set too high, do not increase the intensity once in "Conv" mode.

?

Attached are the numerous warnings in the 1973 manual and the label that is attached to the cover of my 141T.

?

David
Re: 8665B noisy signal & Cal Errors

 

Hi Dave,?
?
?
Thanks for your reply, and great question! The span was approximately 170 KHz between spurs.?

I did the MW Calibration and no change. I took the A14 assembly (GaAs divider, MW Loop, attenuators, etc.) from my known-good unit and swapped it out, no change.?

Someone on eBay was selling a the entire rack of cards (minus the A14, which is why I tested with my good one), including the COAX DISC and Delay Line card (which mine has) so I elected to just buy the whole lot, rather than keep swapping out cards from my good unit, and risk damaging them. Hopefully I'll have more to report back in a week!?
?
?
Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on

 

I 100% agree with you, that's not something i'd like to do, i personally wouldn't have thought of doing that. That's what the seller told me so i tried it too.
?
Pushing on the INSTR PRESET button can also sometimes cause the same thing to happen, it's just less likely to do it.
?
Thanks everyone for the help, i'll probably be back in a few days after i'll receive the logic analyser and do signature checks. If i can't find any issues then i'm gonna wait till i find another broken 8568a and try swapping the A15 board.
Re: HP 141T Power Supply Help Needed

 

I guess that refers to a past topic/thread in this groups archive.

The "Reference" is the neon tube, replaced by solid state parts.

Dave B (UK)
Re: 8665B noisy signal & Cal Errors

 

Question.

What was the span/division, and sweep speed (need to state / div, or full sweep rime) when that video was taken?

Do the spurious sidebands become less wayward. If the sweep is line triggered?

There is information there, that may help.

73.

Dave B (UK)
Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on

 

On 9/23/24 16:35, azpo1928r@... wrote:
Also, i completly forgot to mention, if i flip the power off then on pretty fast i get random stuff on the screen, like lines, garbeled text-looking stuff and things like that. It always did that. They last for multiple seconds.
That's a great way to blow up the power supply in just about anything electronic.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on

 

I just realised something really important :
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The service manual says "if the ADRS'D LED flashes without INSTR PRESET pressed it indicates A13 is functionning but cannot communicate with the controller processor"
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The ADRS'D Led is indeed flashing on my unit... never realised it wasn't normal...
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Btw, INSTR PRESET button is working just fine, i've tested it.
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So that probably narrows it down to A15 right?
?
If i remove A13 (hpib board) it doesn't blink anymore but still got the same two instr check leds.
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Also, i completly forgot to mention, if i flip the power off then on pretty fast i get random stuff on the screen, like lines, garbeled text-looking stuff and things like that. It always did that. They last for multiple seconds.
?
I just ordered a cheap usb logic analyser, i will do signature analysis checks.. in the meantime i'm searching for A15 and A14 boards online... people are selling them for more than double the price i paid for the whole unit (the 2 parts + the two cables + 4 volumes of manuals about it).
?
Seems cheaper to just buy a non-working RF part and try swapping the boards like you said...
Re: HP 141T Power Supply Help Needed

 

There is another design from Philips, they replaced a 103V reference tube, with a circuit based on two transistors, two resistors and a low voltage Zener diode, I keep meaning to try this someday, pdf attached.
?
Note: The resistor values will need altering for the 82V reference, used in the older HP 140 & 141 series mainframes.
?
David

V103 mod for PhilipsPM3262 family.pdf
V103 mod for PhilipsPM3262 family.pdf

Re: HP 141T Power Supply Help Needed

 

¿ªÔÆÌåÓý

Dave,

?

How do I view ¡°141T reference replacement¡±?? Are there PCBs available? If so what is the price?

?

Mike

?

From: [email protected] <[email protected]> On Behalf Of Dave Wise
Sent: Monday, September 23, 2024 11:24 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

Already done, see ¡°141T reference?replacement" topic and photo album.

?

Dave Wise

From: [email protected] <[email protected]> on behalf of Michael Bafaro via groups.io <m.bafaro@...>
Sent: Monday, September 23, 2024 9:04 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

Bill,

?

The 141T that I purchased from Valuetronics now has a new fan and the power transistor sockets have been replaced. Now the 1A fuses on the 8552 IF module are popping.? I built a fixture that I can monitor the basic supply voltages with out the plugins in and the 141T covers on.? ?It turns out that there is an over voltage crowbar circuit in the IF module that fires at -15V.? I took some startup scope traces and they show that the -12.6V over shoots to -15.2V and the +100 overshoots as well.? Since these are tracking regulators and the basic reference is the neon tube in the +100V supply I tested it during startup and it overshoots badly.? Enclosed are some of the startup scope traces I took.? I am working on a circuit that will replace the neon tube with a 50V Zener in series with a TL431.? Since the 50V Zener will be inside the control loop its temp coefficient will not be an issue.? I will publish the TL431 design later in the week.?

?

Mike

?

From: [email protected] <[email protected]> On Behalf Of Bill Berzinskas
Sent: Friday, September 20, 2024 11:30 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

CONV mode is the only functional mode, i get blooming at almost any intensity / persistence setting in storage mode unless its so low its basically OFF.? ? ? ??

?

On Fri, Sep 20, 2024 at 12:21?PM factory via <bobradios11=[email protected]> wrote:

Beware of using the 141T in "Conv" mode, you cannot see if the intensity is set too high & causing damaging the storage mesh. You need to start with it in storage mode and turn intensity down to stop the blooming, then switch to "Conv", if there is any blooming, the intensity is set too high, do not increase the intensity once in "Conv" mode.

?

Attached are the numerous warnings in the 1973 manual and the label that is attached to the cover of my 141T.

?

David
Re: 8665B noisy signal & Cal Errors

 

Special Function 320, instrument self test.?
Re: Efratom MBF distrib amps

 

On 9/22/24 17:50, Wilko Bulte wrote:
My pal Robert PE1MJA took the time to reverse engineer the MBF so all credits to him! And no guarantees there are no mistakes, goes without saying I suppose..
The trick is playing with the caps to peak the filter to 10 instead of 5 MHz.
Ahh, this is very handy, thanks Wilko. Please extend my thanks to Robert as well.

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: HP 141T Power Supply Help Needed

 

¿ªÔÆÌåÓý

Already done, see ¡°141T reference?replacement" topic and photo album.

Dave Wise

From: [email protected] <[email protected]> on behalf of Michael Bafaro via groups.io <m.bafaro@...>
Sent: Monday, September 23, 2024 9:04 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed
?

Bill,

?

The 141T that I purchased from Valuetronics now has a new fan and the power transistor sockets have been replaced. Now the 1A fuses on the 8552 IF module are popping.? I built a fixture that I can monitor the basic supply voltages with out the plugins in and the 141T covers on.? ?It turns out that there is an over voltage crowbar circuit in the IF module that fires at -15V.? I took some startup scope traces and they show that the -12.6V over shoots to -15.2V and the +100 overshoots as well.? Since these are tracking regulators and the basic reference is the neon tube in the +100V supply I tested it during startup and it overshoots badly.? Enclosed are some of the startup scope traces I took.? I am working on a circuit that will replace the neon tube with a 50V Zener in series with a TL431.? Since the 50V Zener will be inside the control loop its temp coefficient will not be an issue.? I will publish the TL431 design later in the week.?

?

Mike

?

From: [email protected] <[email protected]> On Behalf Of Bill Berzinskas
Sent: Friday, September 20, 2024 11:30 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 141T Power Supply Help Needed

?

CONV mode is the only functional mode, i get blooming at almost any intensity / persistence setting in storage mode unless its so low its basically OFF.? ? ? ??

?

On Fri, Sep 20, 2024 at 12:21?PM factory via <bobradios11=[email protected]> wrote:

Beware of using the 141T in "Conv" mode, you cannot see if the intensity is set too high & causing damaging the storage mesh. You need to start with it in storage mode and turn intensity down to stop the blooming, then switch to "Conv", if there is any blooming, the intensity is set too high, do not increase the intensity once in "Conv" mode.

?

Attached are the numerous warnings in the 1973 manual and the label that is attached to the cover of my 141T.

?

David
Re: HP 141T Power Supply Help Needed

 

i either get no trace at low intensity or blooming just after a background green fill.? ? ?I've been going through the 8552/8554 so I haven't paid it much mind but I do need to come back to it.? ? Will look over the A5 details soon.?


On Sat, Sep 21, 2024 at 5:04?AM Dave_G0WBX via <g8kbvdave=[email protected]> wrote:
Does it "Bloom" with the trace intensity set to minimum?

It does look like the storage sub-system needs attention.

Dave B. (UK)


--

Created on and sent from a Unix like PC running and using open source software:
Re: 8665B noisy signal & Cal Errors

 

What is "special 320" ?



On Mon, Sep 23, 2024 at 9:56?AM W4PJB via <petebibbyjr=[email protected]> wrote:
Quick update: I put the unit in self test (Special 320) and got code +2,433,311. From the code list, this appears to need MW Loop Adjustment.

I will do this cal and report back!?
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