[AMRadio] Ramsey AM-25 BC transmitter...need help


Edward B Richards zuu6k at juno.com
Sat Mar 1 11:12:34 EST 2008


Hi Guys;

Someone on this reflector was kind enough to send me a manual on subject.
Unfortunately the schematic is confusing to me. All the lines that cross
each other have no designation as to whether they connect or just cross
unconnected. Usually a schematic will have a dot where lines connect and
no dot for just cross-over or a hump to designate crossover and no hump
if they connect. This schematic has neither. All the cross lines look the
same. I cannot tell which ones are connected and which ones just cross
over. Also, there are practically no voltages given, nor the function of
Q1 & Q2 which look like a voltage regulator, but what voltage? The
transmitter has severe distortion. It actually sounds better tuned off
the center, to either side. I suspected it was FMing but cannot prove it.
The carrier is steady with modulation on a scope. I traced the audio all
the way through to the antenna and it sounds good but the detected
carrier is badly distorted. The voltages around Q3, the PA transistor
look suspicious but I don't know what they should be. I replaced Q3 twice
with no improvement. The RF injection has some very distorted wave forms
but the carrier looks good thanks to the flywheel effect of the final
tank. Can any one shed some light on this problem for an inept technician
that does not understand his computer? Please respond off line to  
zuu6k at juno.com  . Thank you.  Ed  K6UUZ


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