I restored one not too long ago. Learned a lot including how to
restring the drive cable. I must have worked on many 606As and Bs when I
worked for Hewlett-Packard many years ago but was appalled that I
remembered so little about them. On mine the rotors of the tuning caps
were decentered and the plates had been severly bent to compensate. I had
to disassemble the thing enough to remove the caps and fix them. I have
just the vaguest memory of something to do with the caps in these guys
having problems. Generally, -hp- stuff of this vintage should set up
better than specs although there were some real dogs such as early 400D/H
voltmeters which were completely redesigned about twice, and some early
200CD oscillators which had several revisions of the circuits particularly
the power supplys. I dont' think there were any really serious revisions
of the 606A but can't be certain.
Agilent has many -hp- manuals on line in reasonably hi-res PDF form,
they may have a better copy than you have. There is also some stuff at the
HP Memory Project site.
--
Richard Knoppow
Los Angeles
WB6KBL
Richard,
This is my frist 606A. I've been digging into this one just trying to get
dust off, etc. Pretty impressing mechanicals in this thing. I've rebuilt
some R390As and this thing is just about as much fun. Love those large
gears that house the oscillator and amplifier coil assemblies.
When I got it, I couldn't turn the range change switch. It turned out to be
just dried lubricant on a few parts. I've cleaned and oiled things a bit
and it works great now. I was very surprised to find calibration to be on
the money for the most part. I tweaked one range at the upper end and I
think all the others were very close on the lower end. The only range I
can't bring into spec is the top range. Not enough L or C to get it rignt
and not sure what to do to correct this.
This one has all HP-branded tubes. It looks like they may have never been
changed from the factory.
Thanks for the reply,
Barry - N4BUQ