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

[Paul Kraemer]

Ian
I am offering solution to problem which sounds very similar to that which I 
experienced with my TV7 tester
I let an incompetant tech use the tester and whatever wrong settings he had 
caused the meter to peg--- VERY HARD. The current through the meter measured 
correct but the meter indicated way wrong. I finally observed something 
physically peculiar about the meter. The pointer had actuall come off it's 
bearing. A well placed smack on the case put it right. Worked perfect ever 
since.
Paul K0UYA

----- Original Message ----- 
From: "Ian Wilson" <ianmwilson73 at gmail.com>
To: <milsurplus at mailman.qth.net>
Sent: Friday, March 25, 2011 1:45 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 #1: can't adjust line to correct meter position
>  It reads low. If I crank it up to max the meter reads in the white zone
> just below
>  the correct line position. However, this gives excessive filament
> voltages. I have
>  measured all the resistors I can get to easily (especially the meter 
> shunt
> and
>  series resistors when in LINE mode), and have checked both rectifier
>  tubes. Unless the meter sensitivity has changed over time, I'm stumped.
>
> 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
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Milsurplus at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>