[Amps] Basic Question Finding Passive Component Up in Smoke
Carl
km1h at jeremy.mv.com
Wed Apr 10 08:53:46 EDT 2013
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 at hotmail.com>
To: <amps at 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
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1430 / Virus Database: 2641/5735 - Release Date: 04/09/13
>
More information about the Amps
mailing list