Hello all,
I tested this tube on a Heathkit IT-21 (it was a spare tube), it tested at 68%. I pulled the 12SG7 from the radio i am working on and it heated up but went to zero under test, radio did work. Tried the spare again and now it goes to zero under test.
I have tested a few more tubes in the socket and they do test.
Did i burn the tubes out or take something out in the tester?
Thanks,
Mitch

:Hello all,
:I tested this tube on a Heathkit IT-21 (it was a spare tube), it tested at 68%. I pulled the 12SG7 from the radio i am working on and it heated up but went to zero under test, radio did work. Tried the spare again and now it goes to zero under test.
:I have tested a few more tubes in the socket and they do test.
:Did i burn the tubes out or take something out in the tester?
:Thanks,
:Mitch
:
Sorry,
I think i had the switches set wroung on the tester. Both tubes are shot, won't work in the radio. I have ordered another one tonight.
Mitch

::Hello all,
::I tested this tube on a Heathkit IT-21 (it was a spare tube), it tested at 68%. I pulled the 12SG7 from the radio i am working on and it heated up but went to zero under test, radio did work. Tried the spare again and now it goes to zero under test.
::I have tested a few more tubes in the socket and they do test.
::Did i burn the tubes out or take something out in the tester?
::Thanks,
::Mitch
::
:Sorry,
:I think i had the switches set wroung on the tester. Both tubes are shot, won't work in the radio. I have ordered another one tonight.
:Mitch
:
T.

PS, you need to find a way to check the calibration on your tester. If nothing else, get some tubes that you KNOW how they test, and compare them to how they test on your tester.
Just because a tube works in a radio doesn't mean it will test good.

:::Hello all,
:::I tested this tube on a Heathkit IT-21 (it was a spare tube), it tested at 68%. I pulled the 12SG7 from the radio i am working on and it heated up but went to zero under test, radio did work. Tried the spare again and now it goes to zero under test.
:::I have tested a few more tubes in the socket and they do test.
:::Did i burn the tubes out or take something out in the tester?
:::Thanks,
:::Mitch
:::
::Sorry,
::I think i had the switches set wroung on the tester. Both tubes are shot, won't work in the radio. I have ordered another one tonight.
::Mitch
::
:
:I hope not from that same source.
:T.
:
:PS, you need to find a way to check the calibration on your tester. If nothing else, get some tubes that you KNOW how they test, and compare them to how they test on your tester.
:Just because a tube works in a radio doesn't mean it will test good.
:
Terry,
ordered the tubes from the source you recommended.

Look at my new post and see if you can comment on the GE 202 we are both working on.
Thanks,
Mitch

Hi Mitch,
Bad luck. These tubes have two cathode connections, which can make them easy to burn out on tube testers. If voltage gets between the cathode connections, the cathode connection inside the tube fuses, killing the tube.

Best Regards,

Bill

:Hi Mitch,
: Bad luck. These tubes have two cathode connections, which can make them easy to burn out on tube testers. If voltage gets between the cathode connections, the cathode connection inside the tube fuses, killing the tube.
:
:Best Regards,
:
:Bill
:
Bill G.
You are correct about this tube.
I looked up the meaning of the (*) on the test chart. Says not to move cathode levers to test for shorts, only one at a time. I moved both and killed the tube.
Thanks,
Mitch

Mitch

While waiting for a replacement tube try 12SK7. In most radios tubes are interchangeable.

Norm

::Hi Mitch,
:: Bad luck. These tubes have two cathode connections, which can make them easy to burn out on tube testers. If voltage gets between the cathode connections, the cathode connection inside the tube fuses, killing the tube.
::
::Best Regards,
::
::Bill
::
:Bill G.
:You are correct about this tube.
:I looked up the meaning of the (*) on the test chart. Says not to move cathode levers to test for shorts, only one at a time. I moved both and killed the tube.
:Thanks,
:Mitch
: