Electronics > Repair
[SOLVED] HP 34401a - Error 612, 613, 615, 617, 618, 619, 621
Zucca:
bobof, you can do it. Open a separate threadand start with little steps and patience.
tggzzz:
--- Quote from: bobof on July 03, 2019, 04:17:50 pm ---Hahahahaha... if you don't laugh you cry. This time the joke is on me!
Saw an auction come up for a load of test gear with a local auction house. 3x 34401A units (1 HP, 2 Agilent) in what looked like nice condition. Got them for what I thought was sensible money for 3 good instruments... Of course, no opportunity to test them.
--- End quote ---
Phew. I'm glad I didn't bid on those :) I decided to spend my money on a 19" rack full of vaguely similar equipment which I haven't checked yet. If and when I can figure out how to use it (!), I'll let people know. If not, I believe contains many many Vishay foil resistors :)
One of the previous items I bought from that auction house went into the rubbish bin, but fortunately I was able to rescue a functional HP OCXO. Another item was only fit for stripping for parts.
OTOH I've had some good things from that auction house, but it is very hit and miss. At least at this time of year there won't have been too much time for stuff to have become rusty.
bobof:
Well, one of the other units did have a bad B side on U201, and rather helpfully my BBQ'd unit's U201 appeared to be OK at a cursory glance, so it got swapped in (beats waiting for Digikey), and Ta-Da! At least now I have one unit that appears fully working. The BBQ unit display was brighter too, so I swapped that over while I was at it.
--- Quote from: tggzzz on July 04, 2019, 01:21:24 pm ---Phew. I'm glad I didn't bid on those :) I decided to spend my money on a 19" rack full of vaguely similar equipment which I haven't checked yet. If and when I can figure out how to use it (!), I'll let people know. If not, I believe contains many many Vishay foil resistors :)
One of the previous items I bought from that auction house went into the rubbish bin, but fortunately I was able to rescue a functional HP OCXO. Another item was only fit for stripping for parts.
OTOH I've had some good things from that auction house, but it is very hit and miss. At least at this time of year there won't have been too much time for stuff to have become rusty.
--- End quote ---
It looks like in this case I've literally bought someone's bone pile... Knowing this now next time I'll temper my bidding accordingly. Hope you have better look with the gear you picked up! At least with one working with a nice bright display it doesn't stand me at much of a loss.
--- Quote from: zucca on July 04, 2019, 01:02:38 pm ---bobof, you can do it. Open a separate threadand start with little steps and patience.
--- End quote ---
Thanks! Will do. I've stripped the burnt corner of the board including the relay. PCB has been properly carbonised in the area so I guess the only way this could be made functional again would be to re-build this area off the main PCB. Board at least looks OK around the relay site, and there isn't much to the circuit so I think it has to be quite do-able (assuming nothing downstream has taken a dirt dive). Maybe with a slim repair board made up with the relay footprint on it to tie the repair board to the mainboard. Oh, and it will want a U201 now it has been scavenged... :)
The last remaining faulty unit had a VFD which had some leakage issue (extraneous dots) and has errors 744,745 for the calibration data. More research needed...
ua4yhz:
Hi everyone. My device has the same errors during testing. Tell me, what voltage should be on the U101-B? I have 0V on all pins. New chip 1SK6-0001 PLCC44 has not yet ordered, decided to consult here.
Dr. Frank:
--- Quote from: ua4yhz on August 15, 2020, 01:58:52 am ---Hi everyone. My device has the same errors during testing. Tell me, what voltage should be on the U101-B? I have 0V on all pins. New chip 1SK6-0001 PLCC44 has not yet ordered, decided to consult here.
--- End quote ---
Hello,
your failure description is meaningless and unspecific.
U101-B is the input multiplexer, and w/o any signal applied, its input pins, and the ouput pins will be of course at or around 0V.
U101 itself very rarely fails, if it turns out later that it's affected, then check if its +5V, +18V and -18V supplies are ok
But please first describe, which modes and ranges are failing, and which are working, then we might track down the error properly.
Frank
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