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Old 10th Dec 2021, 6:04 pm   #1
Bufo Bill
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Default HP 182T: Scope plugin friendly?

Hi, bought a HP 182T for use with HP 8558B Spectrum Analyser. I thought these were just for SA plugins, but I see 250mV and 10V calibration points on the front, so I am wondering if it operates as a scope too. If I could run my scope plug-ins on this . . . Ooh! Bit scared to try in case something goes bang.
Your advice would be most welcome.
Cheers from Bill.
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Old 10th Dec 2021, 6:37 pm   #2
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Default Re: HP 182T: Scope plugin friendly?

HP182T. The manual says (eventually as they would like you to buy a 182A as well as a 182T) that the 182T can take the real time plug-ins as well. It quotes 1801 DT 50Mhz,1803 ST offset,1804 4T 50Mhz,etc, and the usual Time Bases, as well as the Sampling 1810A, TDR and Frequency domain. Dated 1976.
The special feature of the 182T is outputs for recorder for use with the Spectrum analyser. Not to be used with the conventional PI.
The HP182A manual says all plug-ins currently (1970) available can be used.

But warns that none of the plug-ins for the 183 series will work. And equally none of the 180 series PI will working the 183 Main Frame. That uses a VHF tube with an additional power supply and slightly longer PIs.
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Old 10th Dec 2021, 7:05 pm   #3
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Default Re: HP 182T: Scope plugin friendly?

Thanks Bill, knew I could count on you.
The resuscitation has not been perfect, the calibrator readings are 125.5 mV, and 5.01V.
Will test the rail voltages later on and report back.
Bill.
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Old 10th Dec 2021, 7:39 pm   #4
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Default Re: HP 182T: Scope plugin friendly?

The manual just arrived, will test A2R17, A2R18, A2R19 voltage dividers later on.
For now, Aloo Madras beckons.
Cheers from Bill.
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Old 10th Dec 2021, 8:10 pm   #5
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Default Re: HP 182T: Scope plugin friendly?

The plug-in list from the 1976 182T manual (scanned by agilent);
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Name:	HP 182T Plug-ins.jpg
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Compatibility list from 1971 180 system brochure (doesn't include "T" S.A. variants)
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Name:	HP 180 System Plug-ins Compatibility.jpg
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The four oscilloscope outputs are not available on the "T" S.A. variants, instead has four Aux outputs, Z-Axis input is present on both.

Also note that certain plug-ins are not recommended for use with the storage CRT variants 181 & 184. e.g. the 1601L logic state analyzer.

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Old 10th Dec 2021, 9:23 pm   #6
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Default Re: HP 182T: Scope plugin friendly?

Thank you David.
Sooo . . . Tried my 1806A and 1820c combo. I cannot get a trace on the screen unless using the Find Trace Button, which shows as an oddly shaped Square wave (see post #1 for reason) when using the calibrator. Oddly this does not happen with the 8558B or with the 1806A/1820c when used in my Hp 180a.
Re the calibrator voltages; the resistors A2R17, A2R18, A2R19 were fine, I see an Electrolytic cap near by which I will test later. Probably should have started with that one.
Cheers from Bill.
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Old 10th Dec 2021, 9:44 pm   #7
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Default Re: HP 182T: Scope plugin friendly?

I'm assuming you verified the PSU voltages before trying the scope plug-ins, something that should always be done with an unknown condition mainframe.
I read this elsewhere where someone bought a scope frame with no plug-ins and damaged their working plug-ins trying it.

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Old 10th Dec 2021, 9:55 pm   #8
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Default Re: HP 182T: Scope plugin friendly?

Hi David, thanks for the help. I checked it was 230V.
Bill.
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Old 10th Dec 2021, 10:08 pm   #9
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Default Re: HP 182T: Scope plugin friendly?

Yes always check the mains setting too.

I meant the regulated PSU voltages that go to the plug-ins.
Just looked through my browsing history, it was this post mentioning a failed pass transistor in a mil-180 series scope they got, damaging their known working plug-ins.

https://www.antiqueradios.com/forums...hp?f=8&t=90779
Quote:
I have what was once the AN/USM-281 from hell. The HP model; it was sitting at a hamfest with no plug-ins, marked "free." Took it home and powered it up, seemed OK, so like a fool, I was lazy and tried it out with my pristine plug-ins from my good HP180A. It then proceeded to blow up the vertical plug-in! Learned my lesson. The scope needed a new pass transistor in the power supply but the plug-in was history (not worth fixing, especially how they are put together.)
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Old 10th Dec 2021, 10:23 pm   #10
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Default Re: HP 182T: Scope plugin friendly?

Ah, see what you mean!
No, hadn't thought to check, will do so tomorrow. Both 8558B and scope plugins are functioning correctly in my 180a mainframe. I have also applied "Bill's mixture" to the connectors, by the way.
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Old 10th Dec 2021, 10:54 pm   #11
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Default Re: HP 182T: Scope plugin friendly?

And looking at the calibrator part of the diagram, it would need the +15V & -100V rails checking before further diagnosis.
If it's anything like my HP scopes, the beam find switch probably needs a good clean.

P.S. I've acquired a 181T recently from PP auctions, surprisingly it was advertised as a 181A, it includes the 1804A four channel & 1825A timebase plug-ins. I've yet to test any of this, been busy working on other items from the same auction.

David
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Old 10th Dec 2021, 11:52 pm   #12
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Default Re: HP 182T: Scope plugin friendly?

Nice find David! What is PP Auctions?
Will take those measurements tomorrow, your help is much appreciated.
Cheers from Bill.
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Old 11th Dec 2021, 2:37 pm   #13
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Default Re: HP 182T: Scope plugin friendly?

They are an auctioneer that sells surplus equipment from businesses & closed companies, they seem to run an online auction of electronics (i.e. test gear & TV broadcast gear etc, no old radios) a couple of times a year, as always take note of the T&Cs, buyer fees and where the item is located, as that is where you collect from (most were at their Aunby site, but not all).
https://www2.ppauctions.com/page/16/sales

They had a number of 180 scopes/SA frames in the last sale (Nov), I just hope the lot of 181/2 SA stuff I didn't buy was in better condition than the older 140 series plug-ins I won.

David
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Old 11th Dec 2021, 5:45 pm   #14
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Default Re: HP 182T: Scope plugin friendly?

Fundamentally, the 182T is a 182A with longer persistence tube to help with slower spectrum analyser scans and somewhat different BNC outputs on the rear (which never really get used anyway). I do mean longer persistence and not a storage tube. If you want storage, the 184A could be used at the expense of a smaller display and the likelihood that the tube has been knackered by inexperienced users. The 853A spectrum analyser mainframe adds digital storage but will not take 'scope plug-ins.

BTW, you mentioned the calibrator readings being off, but did not say how you are measuring them. Can we assume that you are just looking at them on screen using the appropriate 'scope plug-ins? If so, are they decent square waves (once any 'scope probe has been compensated for that plug-in?

Last edited by Humber888; 11th Dec 2021 at 5:52 pm.
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Old 11th Dec 2021, 6:03 pm   #15
Bufo Bill
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Default Re: HP 182T: Scope plugin friendly?

Hi, LT rails all fine.
With regards to plug in voltages, I take it we start at contacts of J1. If I have read my schematic correctly, pin 16 should have power, but actually has no voltage that I can measure. I verified my counting on the pins by reading pin 27, which should be -100V, which reads correctly on my machine.
Does anyone follow me there? I can post a snippet of schematic if necessary. Hoping its just a duff wire on pin 16.
Cheers from Bill.
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Old 11th Dec 2021, 6:28 pm   #16
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Default Re: HP 182T: Scope plugin friendly?

Disregard last post my counting was wrong! Will return later with better info.
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Old 11th Dec 2021, 7:50 pm   #17
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Default Re: HP 182T: Scope plugin friendly?

Hi, progress has been made. I measured all the pins on J1 that seemed relevant, counting correctly now, and all was fine. I had cleaned and cleaned the contacts and switches, and gave it another shot. Bill's mixture gave me a sort of ghost of what should be there, and another scrub revealed a nice image at last. I must have spent a full quarter hour polishing!
So, excitement over, we turn to the calibrator again. As I said, the rails measured fine; the +15V was +15v and -100.3V for the other in question. So we still have 125.5mV and 5V on the calibrators.
Thanks for sticking with me, this is so much fun, hope you are not too bored by it all.
Many thanks from Bill.
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Old 11th Dec 2021, 9:09 pm   #18
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Default Re: HP 182T: Scope plugin friendly?

Should the measurement be peak to peak? That would explain things! Still making stupid mistakes.
Bill.
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Old 11th Dec 2021, 9:18 pm   #19
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Default Re: HP 182T: Scope plugin friendly?

OK as all the rails are correct, next would be to check the waveforms shown on the diagram with a known working scope. Transistors are a standard part 2N3440 and the diodes are listed as 120V (can't read the part number), C1 is a high quality 150D tantalum, can't quite read the other C4 but suspect it's an ordinary 30D electrolytic.
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Name:	HP 182T A2 calibrator circuit.jpg
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You mention the calibrator output was an odd shape, coincidently my 181T has a sloping top to the calibrator square wave, will add a picture later.
Everything else seems to work, I checked the PSU rails on the test points on the PCB at the back, I found many switches had dirty contacts, who knows how long since it was last used. I used a sine/square oscillator to confirm the problem was the calibrator output and not elsewhere.

David

Last edited by factory; 11th Dec 2021 at 9:31 pm. Reason: error 181A changed to 181T
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Old 11th Dec 2021, 9:29 pm   #20
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Default Re: HP 182T: Scope plugin friendly?

Hi David, many thanks for the encouragement. A good clean has worked wonders. The dirt that has come out of the switches! Visible crud when I got in there with the servisol and a little paintbrush! I need to be more patient with my cleaning.
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