TV-7B/U Meter reading 120 on 6L6 Tube

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denimdragon

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Joined
Nov 21, 2019
Messages
4
This is most likely an operator error, but the booklet say that a good 6L6 should read 43. I tried two NOS 6L6s and the meter went right to 120. Now take this
all with a grain of salt because I am new to tubes, and tube testing. However, I read/take instructions pretty well so I believe I am doing everything correct. I guess
my question here is, is that normal for it to read that high?

I have diassemblied the unit because whenever I get old gear, I inspect it to make sure that there isn't any obvious visible issues. I have already replaced the bathtube
capacitor the was attached to the meter terminals and replaced it with a new 100uF 35Volt Rubycon. The old cap was 75uF and I followed a youtube video on how
to calibrate and restore it (Blueglow Electronics). Mark seems pretty knowledgeable about the testers and was the reason I hunted down the TV-7 unit intially. The
Aplitrex AT-1000 is above my pay grade.

Any guidance on this would be greetly appreciated as I have 1000's of tubes that need testing and I want this to be my main box. I have a Knight 600B, but from what
I have read here, it's good for emmissions testing, so I will use it for that as a way to quick all the tubes before I put them on the TV-7.

Again thanks for any advice on these matters.
 

mjrippe

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Joined
Dec 27, 2011
Messages
2,571
Location
Brooklyn, NY
Well, there are a few possibilities. Simplest would be an incorrect setting of either the bias or the range switch.

When you say "calibrate and restore it" are you referring to just changing that one cap or a full cal of the entire unit?
 

denimdragon

New member
Joined
Nov 21, 2019
Messages
4
Well, there are a few possibilities. Simplest would be an incorrect setting of either the bias or the range switch.

When you say "calibrate and restore it" are you referring to just changing that one cap or a full cal of the entire unit?

Thanks for the reply. I'm doing a full cal of the entire unit. Also my settings were spot on. I'm going to put it back together here in a bit and give it a go once again. Then I'll see what the results are and take it from there.
 

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