HP 214B Pulse Generator repair question

The manual is on the BAMA site. google BAMA

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Thank you for your swift reply -- but unfortunately, that sites offers the exact same diagram/manual file I already have. The trouble is that there's no parts list included, so I can't look up any component values.

So any suggestions are still appreciated :-)

Best regards,

Richard Rasker

Richard Rasker wrote in news:4c8508bf$0$729$ snipped-for-privacy@textreader.nntp.internl.net:

try this;

or;

Great find, but once again, it doesn't feature a parts list that I can find; the text also doesn't mention the type or ratings of output tubes or fuse.

I'm afraid that all manuals available on the Internet are based on this one -- they're eerily alike, especially the front page photo scan is identical in all cases. I'll try contacting Agilent, but something tells me that this may well be the only information they have available, so the outlook isn't particularly favourable :-(

Anyway, thank you for your efforts (mr. Terrell as well).

Richard Rasker

I used to work at HP. I'll post to an HP alumni technical list and see if anybody who used to design / build / support these things responds.

Bob Pownall

Look for labels, or silk-screened indications of the fuse type and rating... you never know. It might be possible to analyze the exploded bits, of course. Collect them all!

If it helps, MJ15003 is rated for 20A, max. The safe-operating-area limit is a polygon on log(I)/log(V) paper with nodes at [ 20A, 10V], [5A, 50V], [0.5A, 140V].

I've repaired some old SW radio gear where it was impossible to get technical data. That never stopped me though. I understood the circuits, mixers, IF, Hartley osc etc.. and applied what I knew typical values existed for the circuit to work. Similar to what you suggest. Same with more recent mosfet power amp from the 80's. Sound Code Systems or SCS. Couldn't find at the time (too early for the primitive internet search engines) any service errata. But I knew the parameters of the devices and what they should spec and effected a repair. The amp is still in service here. If the OP has a couple blown MJ's and a toasted fuse that shouldn't require scientific intervention.

Richard Rasker wrote in news:4c852e0e$0$729$ snipped-for-privacy@textreader.nntp.internl.net:

maybe these links will help;

good luck.

Artekmedia have the full manual, I guess you can get it as download off their website if you contact tthem, ( Artekmedia.com ) but its listed as a CD on Ebay , search # 370162101455

JC

That would be great, thanks!

Richard Rasker

I'm legally responsible for whatever goes wrong (further damage or injury) if I put in the wrong parts, most notably fuses. Furthermore, this thing is used in a university laboratory by quite a number of people, so I really need to get it right. So in this particular case, guesswork is out of the question (but if I had to guess, I'd say that the fuse should be something between 1 and 4 amps, and the tubes look quite similar to PL519's).

Richard Rasker

Try getting it from the Agilent site:

I'm having a problem downloading it (hangs 25% of the way through) so I can't tell if it's the same as the one on BAMA.

Never mind. It's the same as the one on BAMA. No parts list.

Put it another way: you're responsible, and want to get the machine both working and working safely. The fuse selection isn't a 'legal' decision, it's a technical one. You'll use technical data, judgement, and take technical advice.

The 'correct' value fuse can't be critically important, if its failure spewed bits of metal in all directions the first time it interrupted the circuit... and you still want the machine back into operation.

This guy just doesn't seem to get it. I could see if he was working on a GE MRI machine or Agilent DNA spectrometer. But this is an obsolete pulse generator from the 80's. Besides repair is he also legally responsible for calibration and certification?

Place an amps guesser in place of the fuse and measure the operating current. Ummm... replace the blown transistors first. Then select a value about 2-3 times the measured current. If you're charging a big filter capacitor, consider a slow blow fuse.

If that's true, then walk away. You were given an impossible assignment, where there is insufficient information to return the unit to its original operating condition without you having to make a decision. Should a liability situation arise, one item the court might need to determine is whether you are competent to repair the equipment. Be sure to document your decisions, supply references, sources, and justifications for your actions. Attorneys just love impressive documentation and paper trails.

I haven't seen any mention of dried out electrolytic capacitors, which are the most common source of failures in 20+ year old equipment. An ESR tester will be required to make the determination. If it still has the original electrolytics in the power supply section, I would be seriously worried. I just repaired an HP 8620A sweep generator mainframe. The major problem was dried out electrolytics.

I buy a lot of older HP test gear off ebay as well as older radios. Most of this gear is 25-60 years old and needless to say, the condition of the electrolytic capacitors is somewhat suspect...

No problem. Get one of these university people involved in the repair so that you have someone available to blame should things go awry. Students are expendible anyway. Be sure to let them make a few decisions. If litigation and liability are you primary concerns, it's always best to have a scapegoat handy.

Life is nothing but a succession of calculated risks, which are call guesswork when they fail.

Spend $150 on a carcass. Look inside for the missing values. Steal what parts are needed:

OK, I got some responses but I'm not sure how useful they are.

The eBay price is $7.50 + $2.25 shipping, so how far wrong could you go?

Sorry I couldn't come up with better answers to your questions.

Bob Pownall

OK, thanks, I think I'll give this one a go. The equipment is definitely worth it, and besides, half an hour of my time is rather more expensive than this.

Richard Rasker