Re: HP 8566B Not Showing Any Signal
Thanks again for the information! Here is a video showing the SA with the attenuator and the coaxial switch bypassed.
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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.
hth, Wilko
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Re: 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.
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I looked for a signal in the front output or the AUX output, NO RF power - All Bands.
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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
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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 !!
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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?
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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 ?
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If there is any suggestion on the next steps, it will help
JOHN
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Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on
What happens if you disconnect the bus cable and then turn on the analyzer? LED 1 should stay on, while LED 2 should extinguish. I suspect both will stay on as they have so far, but if things change it may be a clue.
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As far as any other easy tests, I would also check all the front panel keys. They have leaf springs in them so that they return to their normally-off position. These springs can dislodge and leave a key in a state where it's always acting as if it's pressed. During preset, the processor checks for that condition. If a key is in such a position, you would get just one of the LEDs remaining on, but I would check anyway because of the age of this analyzer.
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The easiest way to check for errand springs is to press each key and note if there is a click. The key should firmly return to its resting position. Keys with missing or dislodged springs will feel ¡°mushy¡±.
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Other than that, check that the processor clock is working. Everything else becomes more difficult to troubleshoot because of the need for a signature analyzer. Even with one of those, chasing a problem can get circular until you have replaced almost every part on a board.
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Pragmatically speaking, if you can find a processor and memory board for sale, it would be easiest to just swap them. Most 8568A (and 8566A) have been updated to ¡°B¡±, which left many unwanted ¡°A¡± boards around. I am not sure if they still show up for sale, but the cost should be minimal due to lack of demand.
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Vladan
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Re: HP 8566B Not Showing Any Signal
That's great info Ed! Thank you so much! I wonder if that is my exact problem, because earlier today when I first got to the SA, nothing that was working last night worked today! I turned it off and on again, and BINGO the cal signal passed through. It makes me think that the relay could be bad and that recycling it caused it to work again. I'll give this a look and report back.
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Re: Operating Manual 8901A wanted
Hello,
Please find attached both manuals that I have on the HP8901A unit.
One is the operating manual, and the other is the service manual.
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Enjoy.
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George
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Re: HP 8566B Not Showing Any Signal
It's not always the attenuator problem in the 8566. Bad contacts in the band selector relay can show similar problems. I thought for a long time I needed to fix the attenuator in my main one, but later discovered (by the exact nature of the symptoms) it's actually the relay. In this case, only the low band seems to go bad due to poor contact, while the high band seems OK. The symptom is severe roll-off at the lower frequencies due to the open contact capacitance in series with the signal. It's hard to spot sometimes because switching bands and ranges cycles the various contacts, and can make them work again for a while. A bad contact in the high band state can go unnoticed for a long time, since the capacitance of an open contact there has much less effect at the higher frequencies.
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It's approximately the same amount of grief to get at either one, so it's good to fully check both whenever possible.
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Ed
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Re: HP 8566B Not Showing Any Signal
Swapped out the A6 module from the spares unit into the "working" unit and it's attenuator is blown too. Lucky me. Same exact issues as before.?
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Re: HP 8566B Not Showing Any Signal
Working through the service manual now. Unfortunately, I only have the service manual for the 8566A version of the spectrum analyzer. Fingers crossed it¡¯s close enough.
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Operating Manual 8901A wanted
Hello all,
a good friend donated me a 8901A modulation analyzer. To take full advantage of this nice instrument, I am looking for the corresponding OP manual.
Unfortunately ko4bb manuals site is still down and Agilent website offers only 8101B.
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Can somebody please provide me the manual.
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Thanks in advance.
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Regards Ernst
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Re: HPIB disk drive as a substitute for SRAM cards
Hi Robert,
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I did send you an email but have not received a reply
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Jim
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Re: HP-IB connector screws
Nice, thanks for the doubler info. Can you share the 10MHz modifications for the MBFs? I'd like to perform a similar modification on mine. I've not been able to find schematics for these.
-Dave
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On 9/21/24 02:29, Wilko Bulte wrote: The MBF are indeed 5 MHz modules modified for 10 MHz. The Rb itself is a 5 MHz FRK-HLN. I added a doubler between the FRK and the MBF as described here:
preview.png
high-performance-frequency-doublerv1-31 <>
PDF Document ¡¤ 1,4 MB <>
<>
hth,
Wilko
On 21 Sep 2024, at 02:44, Dave McGuire <mcguire@...> wrote:
?On September 19, 2024 3:42:54 AM "Wilko Bulte" <wkb@...> wrote:
I've been accumulating T&M kit into my ham shack for quite a while now. The shack is in the attic which makes for a cozy but sometimes crowded workspace. I did, interesting maybe, choose the smallest room in the attic. Knowing full well I can easily fill the entire attic (say 5x the shack floor space) with kit as well.
Recently I added some steel strips for load distribution of the table's weight. This HP stuff is mighty heavy, and stacking does not help for "point loads" (does that translate, "puntlast" in Dutch). ?Yup, point loads.
?I see a nice Efratom MFS in there. ?Are your MBF modules the 5MHz versions modified for 10MHz?
????????????????????-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
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Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on
Thanks for the info. I actually forgot to mention the stuff i tried :
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- Cleaning all the board connectors and removing them + visually checking them (no rust, no leaking capacitor, no oxidation)
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- Checking voltages (all seem good)
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- tried to give it 10MHz from a signal generator and switching the 10MHz reference to external, absolutely no difference
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I also have the original service manual.
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The memory is separate, it's on A14 board btw.
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I'm gonna check continuity for all connections on the bus cable. I tried wiggling it around etc but i got nothing. Maybe there's a broken wire in there.
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Btw the seller i bought the SA from told me he tested the display part on his hp8568B and it worked just fine. But who knows if he used the same bus cable or not... the fault may be here
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If it's not the bus cable, what else should i try? I'm gonna buy a cheap usb logic analyser and use it as a signature analyser, i may be able to determine where is the fault located...
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Does anyone here have some "tricks" to find out where is the fault, without having a signature analyser? I have a scope.
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Thx
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Re: Probe Cables for 16801A Logic Analyser
eBay have got some very weird rules lately. They also have problems shipping to Germany.
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Global were able to relist the items for me under a different heading and got eBay to list it for me (these were for 100mm ground leads, not something that needs CE marking) but it was still pretty expensive. I used MyUS.com instead as an experiment but it turned out even worse. I think the problem is that ebay also use a reshipper (Pitney Bowes) and there is the cost of shipping from the seller to pitney bowes, the cost of processing the package (opening and repackaging to check it is as declared) and the cost of prepaying any duty and VAT to avoid a collection fee at the UK end as well as the actual shipping.
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Global made a mistake. They sent me two ground leads instead of two packs. So for my ?76 I got 2 ground leads (the one from breakout pod to ground, not the short one from a single-signal termination housing to local signal ground). I was concerned that MyUS.com had dropped them on the floor, but that seemed unlikely given how they were packaged, and Global readily agreed that their packer had misunderstood. They immediately sent the missing leads by letter post at a cost of a couple of dollars, which is why I'm happy with them.
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But ebay suck. I hope they lose a ton of sales with this crazy system.
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Ok. I remember that, now.
Clearly, I need to find my copies of "The Past Through Tomorrow" and "Time Enough for Love" and re-read them. I particularly need to re-read the chapters in TEFL entitled "Excerpts from the Notebooks of Lazarus Long", which Heinlein used as a vehicle to collect random pieces of his wisdom, right or wrong. "Specialization is for Insects" has always been my favorite quote.
DaveD
KC0WJN
Thanks for all the fish.
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All spelling mistakes are the responsibilty of the reader (Rick Renz, STK, ca. 1994)
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On Sep 22, 2024, at 00:57, David C. Partridge via groups.io <david.partridge@...> wrote:
?And the final part of the challenge response is "Not while the evil days come not." So the full Howard challenge/response went:
Caller: Life is short.
Responder: But the years are long.
Caller: Not while the evil days come not.
D.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Dave Daniel
Sent: 21 September 2024 15:14
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Introduction
....but the years are long.
I almost missed that. Another "like the hot kiss at the end of a wet fist" moment.
DaveD
KC0WJN
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And the final part of the challenge response is "Not while the evil days come not." So the full Howard challenge/response went:
Caller: Life is short.
Responder: But the years are long.
Caller: Not while the evil days come not.
D.
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Dave Daniel Sent: 21 September 2024 15:14 To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] Introduction ....but the years are long. I almost missed that. Another "like the hot kiss at the end of a wet fist" moment. DaveD KC0WJN
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Re: HP 8566B Not Showing Any Signal
Tomorrow I'm going to pull the attenuator out of my spare 8566B, and hopefully, it will work better.
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Re: HP 8566B Not Showing Any Signal
Made some progress tonight. I bypassed the attenuator and ran the -10dB Cal source directly into where the output of the attenuator connects (sorry, I don't remember what that's called). We're getting a signal on the scope now, which is some progress! Here's a video showing how it's going. I'm curious why I have so many harmonics of the signal...it almost seems like something a square wave would have. And the ~80MHz signal that is ALWAYS there is intriguing.?
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Re: Probe Cables for 16801A Logic Analyser
Global cant ship to the UK due to Ebay rules apparently, but I can buy off their website without any problems
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Re: HP 8568A Spectrum Analyser not booting up. Both INSTR CHECK Leds on
The first thing I would check is the bus cable connecting the two boxes. Then, I would verify that all the power supplies are working.
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If that doesn't help, I would re-seat the boards in the processor cage. It might help to find out if yours really is a 8568A. It may have been converted to a "B". The "A" has a separate memory board, while the "B" has memory on the processor board. If it is an "A", check also the NiCd battery pack which usually leaks and does some damage. The service manual has useful information regarding the two Check LEDs.
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Vladan
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Brad Jackson
Dave McGuire
David C. Partridge