[Collins] 75S-3C

[Carl]

----- Original Message ----- 
From: "Dr. Gerald N. Johnson" <geraldj at netins.net>
To: <collins at mailman.qth.net>
Sent: Wednesday, September 03, 2014 12:24 AM
Subject: Re: [Collins] 75S-3C


With it sitting unused, you will need to care for the aluminum
electrolytics that have moved towards self destruction. Probably need to
replace all, and if the black beauties haven't been replaced they need
to be replaced too with orange drops because they are all leaky.

** Orange Drops are a complete waste of money and space for large values and 
besides, they are now made in China as that division has been sold at least 
twice since Sprague went away.
The axial lead film caps are just as good, smaller, and arent as ugly.



I haven't any experience with the tubesters, but if you go back to tubes
you will probably have to replace tubes more often and replacing tubes
next to tuned circuits usually means a bit of alignment is needed for at
least those next to the replaced tube.

** Maybe in the RF and first mixer but the wise thing to do is buy a couple 
from the same batch or at least manufacturer so spares are readily 
available. If a tube swap requires a drastic realignment then Id be 
concerned about the old or new being a problem as long as the old was 
realigned only when new. Normal aging should not require realignment as that 
set has more than adequate gain available to compensate.

Carl
KM1H