Well, if you grounded the B+ on the plate side of the RF choke, you could have heated the
choke enough to make smoke without burning it out. It would probably be discolored in that
case.
Where did you ground the B+ and what was between that point and the power
supply?
On 4/9/2013 8:41 PM, john starr001 wrote:
I am a beginner learning amplifier basics and decided to build a simple 6146
class C final CW rig with a 6CL6 driven crystal oscillator much like the Eico
720 or Globe Scout. The power supply is a full bridge 600v B+ and 300v
non-regulated screen supply. I did something stupid and accidentally grounded
the B+ supply. So I blew the 3A AC line fuse but just before one of the
components in the 6CL6 or 6146 circuitry went up in a cloud of smoke. I have
visualized every cap, resistor and inductor and find no damage. I have
measured every resistor, directly or indirectly, in-circuit and all are to
spec. No open inductors and no shorted ceramic caps (all in -circuit). I
tested the power supply disconnected from the RF circuit and the supply,
without load seems fine. The 6146 and 6CL6 test fine as well. I want to put
it all back together again and test the voltages with the 6146 and 6CL6 removed
but I am a chicken worrying about blowing up something else (like my transfomer
t
he next time). There was a obvious puff of smoke so something was lost. I
figure approaching this kind of problem must be routine for you guys working on
amps so would appreciate learning what would be your next steps to find the bad
part while minimizing further damage. I thought the 6146 screen would burn up
if the plate B+ were suddenly lost but it tests fine on my Hickock. tnx and
73john
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Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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