"John Cusick" wrote in message
news
OK, I'm really not sure if this is a dumb question or not... and it seems
to me that this is the place to ask.

I have a box of old radio tubes (15 or 20) that physically look NOS, but
the identification of each has been rubbed off with time and handling by
various non-cautious people.

Is there any way to identify an unknown tube type? I have a tube testor,
O'scope, pwr supply, and other various pieces of test equip.and I hate to
throw these away since I have a few old radios I would like to repair, and
may have a use for them.

I'm hoping there is a method that is simpler than hanging around Ebay for
a month in case I need a few and one of mine end up in the garbage due to
lack of ID.

Regards,

John C.

Jeesh... Looking & recognising the 'family" is the first thing - at least
you'll know if it's a triode, pentode, beam toob, whatever. In 9-pins,
it's really easy to track the pinout - that will tell a bunch.
Now for the "tricks which may or may not work" part:
Put tubes in the fridge for a few minutes. Then breath on them, rotating
them slowly - sometimes rubbed-off stamp /screen will become clear ewnough
to read.
If that fails, wipe the tubes with 8windex*, and try the same trick - once
again, works sometimes.
Basically, if you've seen a whole bunch of toobs in your life, you can tell
which's which 'cos you've seen them before...

A little household amonia on a t-shirt can sometimes bring up the numbers if
they're not gone altogether.

R

John Cusick wrote:

OK, I'm really not sure if this is a dumb question or not... and it seems
to me that this is the place to ask.

I have a box of old radio tubes (15 or 20) that physically look NOS, but
the identification of each has been rubbed off with time and handling by
various non-cautious people.

Is there any way to identify an unknown tube type? I have a tube testor,
O'scope, pwr supply, and other various pieces of test equip.and I hate to
throw these away since I have a few old radios I would like to repair, and
may have a use for them.

I'm hoping there is a method that is simpler than hanging around Ebay for
a month in case I need a few and one of mine end up in the garbage due to
lack of ID.

Regards,

John C.