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

[John Hutchins]

Ian -

I rebuilt, oh yea - Calibrated, - my I177-a a few years back.  I found 
all the carbon resistors were > 10% out of spec.
The single cap was also replaced 510 pf and .1uf caps.  I used 1% Metal 
film resistors. Ceramic and mica caps.
Good luck
-Hutch


On 3/25/2011 2:04 PM, DeWitt Clay wrote:
> #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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