HP-8601A

BARRY'S 8 TRACK REPAIR

Restoring the HP 8601A RF Generator/Sweeper

I was fortunate enough to purchase this item along with several other vintage HP
gems from a retired Avionics Engineer. Since this equipment was used in an
Avionics shop, it was kept in perfect calibration and working order. The only bad
thing is that it had not been used (or even turned on) in about 10 years. Thankfully,
this unit still worked fine except for the usual dirty controls and a lot of dust.

Some diligent work with rubbing alcohol, WD-40, rags and Q Tips took care of the
dirty front panel and switch operation. As with much HP equipment, many of the
controls are sealed and cannot be cleaned (well, you can usually sneak a feeble
squirt of contact cleaner into the tiny spaces between the terminals and the housing
if you're lucky). All in all, this little gem cleaned up very nicely as you can see.

The mechanical readout on the upper left needed some TLC, as a portion of the
digits were somewhat discolored. By now, you probably know that I like my test
equipment to look as close to brand new as possible. Well, the moment I touched
my alcohol-dipped Q Tip to the digits, they immediately vaporized and disappeared!
The paint had dried up and was only clinging to the mechanism by sheer hope.

It was obvious that the entire readout needed to be reconditioned - somehow. I
brought home a very fine white paint pen, a small container of white paint and a
few tiny brushes, not really sure which method would yield the best results. As it
turns out, both were horribly inadequate for the application. There was no way I
was going to be able to reproduce the neatness and exactness of the original.

Finally, the Fone Brainstorm kicked in! I ended up printing a bunch of white-on-
black digits on my favorite laser printer (an HP Laser Jet 6P), meticulously cutting
them into tiny rectangles, and got out my trusty tube of clear RTV. Using a pair
of tweezers, I painstakingly positioned the tiny digits onto the display. I had to
pre-curve the tiny paper rectangles so they would match the shape of the drums,
of the corners would come up. The end result, however, was well worth the few
hours I spent on the job. In fact, they are slightly smaller than the original digits
(thus making them a little easier to read), and even line up a little better:

You really couldn't ask for better results - BETTER than the original!

The HP 8601A is an RF Signal Generator which provides
frequencies from 0.1 MHz to 110 MHz, has inputs for AM
or FM modulation from an external source, and has other
features such as variable sweep width, output level - and
a CRANK to change frequencies quickly, with the readout
offering near-perfect accuracy without an external counter.
Its range and features make this piece of equipment one
of the most useful apparatus for AM-FM radio servicing.