Signature Analyzers ? ? ?

[George_Race]

I am looking at several different Signature Analyzers.

 Sony/Tektronix 308, HP 5004A, HP 5005A & B  and the HP 5006A

I work on a lot of old HP equipment that uses signature analysis.  I understand that the TEK and HP are compatible and will read the same signatures.

I am interested in hearing from others that have used the above instruments.

Your recommendations and comments would be appreciated.

Thanks,
George

[merox]

I own an HP 5005A but i've never used it for signature analysis. Basically I only own it because I was able to get two of them for cheap (<15€ for both together).

One was operational, the other one broken. If I remember correctly it was an easy fix, one of the display drivers on the display assy was broken and interrupted the processor bus. But beware, these devices contain quite a lot of ECL logic which is pretty much unobtainable by today (For that reason i've got an unfixable 5326B laying around). So if you buy a broken one, you may end with an unfixable brick.
Since these devices are mostly over 35 years old (my device contains chips dating between 79 and 81) the cable connecting the probe to the 5005A might also be a (fixable) problem. It consists out of a very flimsy coax-cable and two or three other "single conductor"-wires. If the device was in heavy use, a cable break can be very likely.

Apart from that the device seems quite stable in terms of long time accuracy. Even after over 35 years my 5005A is still in spec. Ohms, Volts and Frequency (and whatever i might have forgotten) - they all work fine.

[free_electron]

the sony 308 is junk. i have one. tiny little picture tube. klunky, unusable

i also have a 5004 and a 5005. the multimeter is also junk. it's a gimmick. nothing more.

apart from that, such a muchine is really very helpful with the hp machinery. i;ve been able to fix at least 10 machines which, without such a device , were hopeless.

[guido]

I also have a 308 (gift); it is usable. The probes are hard to get though.
I used it on a HP3456A and could get the signatures, no problem.

Mine developed a fault once; a regular elco shorted out. I've swapped all of them.
It is not much of a LA, but usable as signature analyser.

[George_Race]

Thanks guys, your really helped to confirm what I just did.  I purchased a 5004A.  I like the smaller size and I really do not need another multimeter.

I liked the looks of the Sony but did wonder about the size of the screen and why they were selling for so little on eBay.

The one I am getting looks just like brand new, is fully tested and guaranteed.  For the most part I only work on older HP equipment so going with the 5004A is probably the best way for me to go.

So thanks again for your comments, sometimes all it takes are a few words from an owner to help convince me of the direction to go.

George

[MarkL]

Just picked up an old HP 5006A from ebay.

It's clearly built down to a price: cheezy plastic case, sheet metal insert "nuts" for some of the machine screws, no connectors for the probes (they're hard wired).  Not at all up to the usual HP test equipment quality I expect from that era.  But whatever, it's not something I'm going to use every day and it gets the job done.

I got a very clean unit, but of the 11 buttons on the front panel, not a single one of them worked except the power button.  Not even intermittently after a bunch of cycling.  The unit responded to GPIB so I was sure it was something with the keyboard driver.

Not the case.  After a 20 minute session with a can of contact cleaner, I eventually got them all working again.  I guess this unit didn't see much action, certainly lately.

I do like the self test feature where you can plug all the probes into the front panel.  It automatically detects you're doing it and let's you know if everything passed or what's failing.

It has a service manual available for it and if you need to fix it, you need... A signature analyzer!

Anyone interested in reading more than you probably want to know about this old debugging technology can look here:

  www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1977-05.pdf

[wn1fju]

I've got both the HP 5005B and the HP 5006A.  As others have indicated, the 5005B has some "extra" features that are better left to dedicated instruments.  As much as signature analysis a cute idea, I don't think I've ever actually found a bad IC using one.  All I've ever managed to do is prove that the digital side of some piece was working correctly and my problems were elsewhere.  Most of my bad ICs were found either by simply looking at them with a scope or hooking up a few pins to a logic analyzer.  Maybe I've just been lucky so far as they mostly were garden variety 7400 or 4000 stuff.  My biggest problem, however, is that a lot of the vintage HP (and other vendor) equipment I've fixed had ROM upgrades and invariably one obtains service manuals without the yellow change sheets containing the updated signatures.