Hallicrafters S-118 circuit diagram sought
 

I was at the Newport (south Wales) radio rally tihs weekend. On an
impulse I purchased a Hallicrafters S-118 for £20 (about $40). I don't
have any valve equipment, so I saw it as a way to get something to play
with.

When I got it home I took off the cover. An additional transformer had
been added above the chassis which was configured as an autotransformer
to transform 240V to 120V, as required by the original transformer (but
it was a bit of a beast). There also had been some modifications to the
antenna connections to bring them more uptodate, so I was worried at
what else might have been fiddled with.

I also did quite a lot of googling to find out more about the reciever.
I was surprised to see that the radio dated from the early sixties -
just like me! I really like the large tuning dial which seems much more
modern than it's true age. When I looked at the build quality I thought
that it was quite sloppy/poor, and I even wondered if what I was seeing
was later modifications to replace older components, but I have come to
the conclusion that most of what I see is original.

I found a service manual on the BAMA website, but the schematic was
virtually un-readable. If anyone knows whether a more clearer schematic
is available freely on the net, please send me the link. Perhaps another
model has a similar schematic, if so please post details. I am
particularly interested to understand the HV power supply and heater
voltage. The schematic just about lets me see that the heater winding of
the transformer might be 12V and that the secondary voltage appears to
be doubled by two diodes. I either need to find a way to transform 240V
to 120V with a smaller transformer than the one which was added, or I
need to replace the original transformer with a UK equivalent.

I am really looking forward to carefully checking out the reciever and
getting it operational again. Any advice would be gratefully recieved.

73 de

--Gary (M1GRY)