On Mon, 22 Sep 2008 01:00:59 -0700 (PDT), charrid
wrote:

Power supply was also my first thought, but Nixies light up and if I
try hard, I can change some digits. Time base fault sounds like a
good bet. Thanks for the hint.

It's probably a simple divide by 10 divider chain. Should be easy to
troubleshoot. Since it probably doesn't work on any range, it's
probably somewhere between the clock oscillator and the first digit
counter. This should be easy (famous last words).

Incidentally, I bought an HP5334A counter on eBay. When plugged in,
it displayed an error messages that indicated the clock section was
dead. I got a really good price on it, so I decided it was better to
fix than to return. I didn't have a schematic yet, and none could be
found to download. After replacing the clock oscillator and the hex
inverter that was acting as an oscillator, I eventually discovered
that the internal/external toggle switch was open. Sounds simple but
this trivial troubleshooting exercise took about a week.
Moral #1: If it moves, it breaks (especially on old equipment).
Moral #2: Simple problems take forever. Complex problems are easy.
Moral #3: That which is most obviously working, beyond any need of
checking, it usually the problem.

I did get to ietlabs site in my first searches. Never thought of
mailing them for a scan, though. I'll give them a try.

It will probably cost you some money, but methinks is worth the
effort.

I'm sitting on a fairly complete collection of Intech marine radio
service manuals from the 1970's. One of my customers has a Canon
Imagerunner 5000 copier and scanner combination that does a totally
impressive job of scanning manuals (hopper feed, de-collating, scan to
PDF, etc). At about 2-3 hours per manual, this is a major project.

old equipment all too often:
http://802.11junk.com/jeffl/pics/home/slides/lab.html
Note: *It's a lab, not a museum.

I don't think 20-30 year old HP's are at all museum pieces - they are
still in their prime.

That depends on what you're doing. For tinkering and experimentation,
it's good enough. For design projects and consulting, it's
inefficient, insufficient in many ways, and barely adequate. For
example, using a digital camera to obtain a spectrum analyzer image is
rather clumsy with my cardboard hood.

Cool. *One question. *Is the frequency range of the Eico the same as
the Heathkit ranges that I listed? *I'm curious.

Eico 710 has 8 coils starting below AM BC band:
L1 0.4 - 0.7
L2 0.7-1.38
L3 1.38-2.9
L3 2.9-7.5
L4 7.5-18
L5 18-42
L6 42-100
L7 100-250

Thanks. Not even close to the Heathkit. So much for that theory.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558