"Stan Shankman" wrote in
:

Questions: HP 8640B signal generator . . .

Greetings all,
I picked up a used HP 8640B signal generator off of eBay. I have
always wanted one, and now I have one.
Mine seems to work okay, but the tuning cavity only requires use of
the clockwise most portion of its range. Much of the counter-clockwise
range is just not needed - even though the frequencies seem to be
okay. Is this normal? I have never used an HP 8640B before so I cannot
say. Also, I noticed that when I remove the top-most counter board
(the board that contains the digital readout segment displays), I see
a smaller compartment that contains the pre-scalar. Judging by the
missing screws, and the overall appearance, it looks like there could
have been a lid on that compartment. Was there in fact such a lid? Or,
is this locations reserved for an option? Also, after removing the top
lid from the unit, I see two strong "RF boxes" the smaller one, in the
front, is the frequency counter (with the 7-segment readout as
described above), and the other box, the big one in the middle
right-most side (looking form the front), is presumably the frequency
multipliers. Now my question is, behind these two boxes, is another
(much smaller) open-lid box that contains a few plug-in cards. But
when looking closely at this box, I see that it too might have had a
lid. Can anyone say for sure if such lids were in fact present when
the unit was new? If so, can anyone provide such spare parts?
Oh, and while I'm at it, can anyone say if it is possible to add
option-002 (the frequency doubler option)? Can such parts be obtained
- perhaps from a dead unit? Or am I better off just finding a unit
that has the doubler option already installed and parting with my
current unit? Thanks,
- Stan Shankman
K7SJB


Rather than attempt to answer some of your questions with possibly
erroneous info, and since you have the manual on file, have you
studied the Service Sheets in Section 8, and especially page 8-73
closely? I might answer some of your questions regarding missing covers,
etc. I haven't dug through the thick manual for reference to your other
items... My manual does not cover any details on the Options, only the
main unit. I'm using HP manual, PN: 08640-90017

Ed K7AAT