In article ,
wrote:
I'm working on a Collins 51J1. Originally came to me with a LOUD HUM but t=
hat was taken care of. Also had a very stiff band switch, resolved as well=
with some drops of machine lube (sewing machine oil). It's receiving on t=
he first 3 lowest bands very well or those being the broadcast band and 2 a=
bove that confirmed. All other bands have a bit of noise but no reception =
and can receive the xtal calibrator signal when turned on. =20

The crystal calibrator injects directly into the 6AK5 front end tube, I
believe. So if you are heaving the crystal calibrator but not hearing a
signal generator plugged into the antenna jack, something is wrong between
the antenna jack and the 6AK5, which is likely to be the bandswitch
control or the tuned input networks.

Sit down with the signal generator and work out the actual input sensitivity
on the various bands, and write it down on paper. There are only six of
those tuned input networks for all the different bands and if one of them is
tuned right and the others are bad it will work on a couple bands but not
others. Also cramolin the hell out of that bandswitch, especially the first
three or four wafers.

Having all the sensitivities on paper will help a lot when you go to look
at the schematic and see which bands go through which paths.
--scott


Seeing as how I'm new to Collins receiver repair but not new to boat anchor=
and old radio repair, what could I do to fix the issue.

Thanks and 74 de,

Gary/N9VU


--
"C'est un Nagra. C'est suisse, et tres, tres precis."