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jakruby 17th March 2010 02:17 PM

Old test gear
 
I am thinking of buying a distortion analyser HP339A, Sound Technology, Tektronix, etc. But i worry because these items are getting on to be almost 30 years old now. As i do not live in usa servicing will be expensive if at all possible. My question is thus is this old gear worth it? I realise that they are extremely well made......or should i just settle for a soundcard/software solution?

Allen Wright 17th March 2010 03:27 PM

Old PROFESSIONAL test gear tends to be VERY reliable. I have a lab full of HP and TEK gear from 30 years ago, and it never breaks down.

But I used to work for HP so fixing it holds no dramas for me as long as I can get the service manual.

The key is to check it over very carefully before buying. Sometimes it's all worn out, other times it's actually never been used.

I have two scopes, one HP and one TEK that each would have cost the price a full sized execuitive car when new, but I bought them for around $150 each - and they were effectively brand new.

But for a hobbiest, a soundcard is most likely the smart decision - I have and use both.

Regards, Allen

jakruby 18th March 2010 08:39 AM

good points thank you

Ashley Ace 18th March 2010 02:38 PM

From my side of the ocean, I`ll gladly agree to the previous point. I have got an oscilloscope made in USSR about 46 years ago. It is all-tube and yet it works fine even without replacing old caps and tubes.
The only disadvantage is its bandwidth. This can be broadened by the measures above, but it seemed enough last time I cought a high frequency oscillation in my amp.
And yes, it looks like there is no power in the world to make it stop working.

Cheers. Ace.

Matt BH 18th March 2010 11:36 PM

I have a HP334A, its been totally reliable and is very well built. The 339 is a much better piece of kit. The only thing I had to do was give it a good clean and clean all the switch contacts as it was a bit eratic but still usable. Calibration is another matter, the set up in the manual is beyond my test equipment. I got a quote of 50 from a UK test house which is not bad at all. I didnt bother though as it seems to be inline with with my other calibrated kit.
Cheers Matt.

Magura 18th March 2010 11:47 PM

I have a few Hp pieces, that are 60 years old. Works just fine.


Magura :)

tomchr 19th March 2010 12:00 AM

+1 for the use of HP/TEK test gear. Many of the service manuals can be downloaded from the manufacturer's website and the remaining can be bought through Manuals Plus, eBay and others. The circuits are well documented and not that daunting to fix if you know a thing or two about electronics.

My instrument park includes: HP8903A, HP3312A, HP3478A, HP3581A, TEK 2465B, TEK 2215, plus a handful of HP power supplies. All salvage or surplus equipment that was being discarded because it was broken in one way or another - except the 3312A and 3478A. I think the most expensive piece of gear was $150 including shipping.

~Tom

Matt BH 19th March 2010 11:26 PM

Completely agree, my TEK2235 was 30 quid with a dead PSU. Pretty easy fix, one resistor had drifted and the voltages were very slightly high. Amazing how picky they are on voltage limits, I only found it accidentaly when I shorted a rail with my meter and it sprang into life. Your 2215 is basically identical and I was using the manual for that model from the excellent BAMA site.
Anything from HP or Tektronix is worth getting if only for bits. Some people would shoot me for that statement and I am slowly coming to the same opinion. Truely great gear.

Cheers Matt.

Allen Wright 20th March 2010 12:41 AM

[QUOTE=Matt.B.H.;2124069]>>>Calibration is another matter<<<

If the unit works well, I very much doubt if the cal is off. I worked at HP in the service/cal lab, and hardly anything we got in had gone out of cal, even after years and years.

Tube gear can go out of cal when tubes are replaced, but yours is SS so I say: No worries. You could use it to cal lesser quality gear.

Regards, Allen

Conrad Hoffman 20th March 2010 01:03 AM

That classic HP and Tek equipment is built to a standard that modern economics has all but eliminated. It's rock stable, but IMHO you still have to learn how to fix the occasional problem. Caps do go bad (but don't replace anything unless it's proven to actually be bad), switches do need cleaning, and anything with batteries needs to be examined internally for damage. One caveat is that most modern hi-fi equipment is better than most older distortion analyzers. You really need both a distortion analyzer and a spectrum analyzer (PC is fine) to learn anything very useful.

Best,
Conrad


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