[Milsurplus] Fixing up an I-177B tube tester

[DeWitt Clay]

#2.
Check the grid, screen, and plate wafer switch decks for bad 47 Ohm 1/2 watt 
resisters stuck in there between or around the wafers on each switch. These are 
in series and act like fuses/parasitic surpressors. They will stress and open 
up from testing a number of bad/shorted tubes over time.
73, DeWitt N4QNX


----- Original Message ----
From: Ian Wilson <ianmwilson73 at gmail.com>
To: milsurplus at mailman.qth.net
Sent: Fri, March 25, 2011 2:45:42 PM
Subject: [Milsurplus] Fixing up an I-177B tube tester

I would have thought this was easy enough that I could figure it out; but I
could
use some help here.

Problem #2: no reading on AMPL
  Nothing happening with a working tube. I can see the filaments are heating
OK.
  Removing the tube and looking at the voltages between plate and cathode
(pins
  5 and 8 for my test tube, a 12SK7) shows nothing (AC or DC) with or
without
  AMPL pressed.

The rectifiers are both lit. I measure 127V to ground on the 83 filament and
130V
to ground from the 5Y3GT filament.

Suggestions welcomed.

74, ian K3IMW
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