zeitguy said:
I am reluctant to open this up unless necessary, but I don't get any
meter movement on any setting with either internal or external
modulation on the 1001. THe scope trace is unaffect also. If I have
to open this up and the tubes are good, what is the next thing I should
be checking? I am pretty novice but have the tools and am willing to
learn. Thanks.
These instruments were quite reliable in their day. You can download a copy of
the GR 1001A model from ftp://bama.edebris.com/bama/gr/1001a/1001a.djvu. It
might have a few differences from the model 1001, but is probably close enough
to give you some help. You'll need the DJVU browser plug-in to view and print
the manual, but it's free and works well. Follow the link on the BAMA page to
get it.
From your symptoms, I'd assume that the RF side is working, and you should
concentrate on the modulation circuitry.
My first suspects would be the switches... the modulation switch and the meter
switch. If either of those has bad contacts, the instrument would have no
modulation. Get a small vial or spray can of DEOXIT contact cleaner (available
from web vendors like
www.mcminone.com. Another thing to check would be the
modulation level pot, and resistors R11 and R14. Diodes D1 and D2 are less
likely suspects, but you should check them as well.
Finally, check for broken wire(s) from the modulation pot, through C14, R11,
C15, L1, C20 and R14.
HTH,
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)
Never take a laxative and a sleeping pill at the same time!!
