Hello all,
Well I got the new investment at home today. The manual refers to a
77S as well, so there was a 2 tube made with the s suffix. This unit was
orginally bought about 1976 to 1977, serial number 2742. It is a full
size case like the DX and SX version. The manual said the S has a bigger
power supply and heaver plate tank circuit components. The guy that sold
me the amp said it is good working condition. After I got home and
removed the top cover, the plate tune vacuum cap has about 200 little
pitts in the internal element. I assume it was way out of tune a few
times and once it became pitted the arcs were easier to get started.
Anyone know if this item is easly found? The book said it was a 400pf at
7500 volts.
The next item of interest was the band switch. It looks like the
contacts are still making but some arcing has taken place. Looks like it
might have been on 10 meters at the time??? I might as well replace that
too.
The next thing which has nothing to do with the operating is the paint
on the outside of the case. The paint is coming off and will need to be
cleaned and repainted, including the front panel.
There is room for an additional tube but no hole was provided. However
there are 4 small holes drilled to hold the tube chimney, from the way
it looks.
It has QSK with a vacuum relay in the output. I have not powered it up
to see if anything else is shot. I probably should do that to see if
anything else major is bad. Any suggestions are appreciated on this
restoration project. Thanks to all that has already sent in the valuable
info concerning this amp.
Ron W4WA
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