You cant really test many of the components with just an Ohmeter, they need
to be under stress.
Try a 1A fuse with the tubes removed and if OK just the 6CL6 and see if it
oscillates. Finally add the 6146 and go to a 3A fuse. The best way is with a
Variac.
Possibly the short just momentarily overheated some component and didnt
cause permanent damage.
Carl
KM1H
Currently refurbing a DX-100
----- Original Message -----
From: "john starr001" <jstarr001@hotmail.com>
To: <amps@contesting.com>
Sent: Tuesday, April 09, 2013 11:41 PM
Subject: [Amps] Basic Question Finding Passive Component Up in Smoke
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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