"ablebravo" wrote in message
ups.com...
this is the first more complex (than s38s) halli have i tried to
repair. as received, the set. set played, but w/out sensitivity or
vol. recapped (not micas) and tested all tubes, replacing as needed.
checked resistors, and replaced a few. set also had severe crackling
which matched 'short in a tuning cap' as described in marcus and levy.
i replaced the tuning condensor, due to remaining crackles i simply
couldn't get out w/cleaning. crackles went away w/partswap and set
appeared to align well -- used scope across output to voice coil. got
good volume and nice waves as i went thru the IF and the band steps.
for IF the sig gen was connected to the center of the gang, the middle
of 3 posts on the top of it, w/the ground to the chassis and the gang
fully open.

radio plays well on band 3 -- good vol on strong station, many stations
w/short wire. picks up similarly on band 2 down to about 4 mhz.

bc is silent except for what sounds like a couple of spots that 'want
to be' stations. very faint voice heard in one spot. band 4 seems to
be similar.

a quick reattach of sig gen, and good tones heard all bands at align
freq for those bands, and good IF tone. bandswitch was checked and
cleaned. seems to be making good contact w/clean click/pop as changed
w/set on. a little puzzled where to look because of this.

docs say make sure the image freq is out of the way of oscillator freq
for bands. i don't quite understand what this means, or how to be sure
they aren't colliding, but i think i may have misaligned the base IF?
maybe aligned with an image of it? have noticed when aligning other
sets, you can find several positions that ring w/the tone, but only one
that rings best. is this the result of getting the echo instead of the
original? care was taken on the rf aligns to find thru most of the adj
range for the best response. but did not try moving the if's
radically.
ab


First, carefully clean the band switch wafer metal wipers with a cotton
Q-tip and some DeOxit.
No need for heavy handiness here -- just good patient (methodical) cleaning.
IF you are short on time or not patient that day -- do something else and
come back to it.

gb