[Test-Equipment] HP-3330B repair: parts needed

[Chris Trask]

Jose,
    I had the eact same problem with one of my HP3330's last year.  I traced
it down to the A27 board, and with some effort found that IC11 (an SN7473)
had expired, possibly due to a supply voltage surge.  I replaced it with a
74HC73, and it has worked fine ever since.  That's the board that locks the
low noise VCO to the noisy synthesized digital signal.

    Those older TTL parts are not very forgiving for supply voltage surges,
and I suffered damage to two pieces of equipment last year when a utility
mains transformer out on a pole failed and caught fire.  The other piece of
equipment was an HP141T mainframe, and I have repaired it also.

Chris

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----- Original Message -----
From: "Jose V. Gavila" <eb5agv at ctv.es>
To: <test-equipment at mailman.qth.net>
Sent: Thursday, July 01, 2004 7:48 AM
Subject: [Test-Equipment] HP-3330B repair: parts needed


> Hello!
>
> Well, as I was still waiting for some other test equipment to try to fix
my
> HP-8555A, I decided to go for an 'easy one'... well... It is an HP-3330B
> "Automatic Synthesizer" which is a 0.1Hz to 13MHz signal generator,
> modularly built and so very easy to service. As I had replacement for (I
> thought) all the plug-in circuits and what happened to it was just an
> slightly off (a couple kHz) frequency, I thought it would be easy to get
it
> working again.
>
> So, armed with the Service Manual, I started troubleshooting tree. It took
> me to locate a faulty VTO module, which once replaced modified just a bit
> output frequency but definitely added stability. Great!!!. Then, following
> the tree and after some checking steps, I got to a point which said
> 'Replace A27 Module'. Ok, no problem, I thought... But YES, there IS a
> problem!!!. I have all modules EXCEPT for that one :-(!!!. I have the
> remnants of no less than 3 HP-3330Bs (except for chassis, covers, ...).
> Well, I have all and every card EXCEPT the one marked as 03330-66518
> ("SL2/SL3 Mixer/Phase Detector")
>
> I hope somebody will be willing to exchange that module for any other
> HP-3330B module. Any taker???
>
> Thanks and best regards,
>
> JOSE
> ----------------------------------------------------------------------
>    73 EB5AGV / EC5AAU - JOSE V. GAVILA
>       La Canyada - Valencia (SPAIN) - Loc: IM99SM
>
>    Vintage Radio: http://jvgavila.com
>    Vintage Test Equipment: http://jvgavila.com/testeq.htm
>    European Boatanchors List: http://groups.yahoo.com/group/euro_ba_swap
>
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