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Old July 20th 08, 11:45 PM posted to rec.radio.amateur.boatanchors
BillJ BillJ is offline
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First recorded activity by RadioBanter: May 2007
Posts: 7
Default Tube tester problem

Don Bowey wrote:
On 7/20/08 12:57 PM, in article , "BillJ"
wrote:

I have Sylvania Electric tube tester. Has worked for many years, but
today known good tube test flat zero. Filaments do light. I have no
model number, it is a green panel, with roll chart.

Anybody know what might go wrong. I looked inside and see one tube, a
1EL7 I think it was. Other wise looks good, with no bad smells.

Thanks, Bill


Check the Meter Movement with a very low voltage and lots of resistance.

Set the tester up for a few tubes, one at a time, and measure the voltages
at the pins. Trace back to source of missing voltages. Wiggle the pots for
affect.

A tube manual will suggest what voltage to expect.

There are probably at least two DC power supplies in the tester. Check them
for input and output voltages. Depending on the vintage of the tester you
may have selenium rectifiers that have a too high internal resistance. Don'
forget to test the capacitors for shorts.

And don't forget.........The internal toob might be shot. Seeing a filament
glow does not a good tube make.

Neither my Sylvania tube manual nor a Google search list a 1EL7.

Have you looked for ti's manual?

Thanks for the tips: meter movement works on line voltage set at mid
scale, so don't think thats the problem. Any idea what the internal tube
is for? I don't see a filament glow, but it's only a 1 Volt,
May have the tube number wrong.
What is the "ti" manual?