[Raymond Koonce]

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

[Alan Douglas]

The only 88s I'm aware of are all rectifiers. Is it possible that
someone swapped bases with another tube?

Alan

[Raymond Koonce]

Alan Douglas wrote:
The only 88s I'm aware of are all rectifiers. Is it possible that
someone swapped bases with another tube?

Alan

Alan,

Here's a shot of everything on the base. Most of it's not intelligible
except for the 488 designation.

Do I have a one-of?

Raymond

[Peter Dettmann]

On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann

[Brenda Ann]

"Peter Dettmann" wrote in message
...
On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann

Voltage regulator, maybe?

[Alan Douglas]

All I can guess is that someone used a dud tube to test the
hot-stamping dies. The longer name looks vaguely familiar
("Commander" first came to mind which was a Chicago maker I think).

Alan

[Raymond Koonce]

Peter Dettmann wrote:
On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann


Hi Peter,

I have some higher resolution photos and there is definitely a grid
visible behind the mesh. I assumed it to be a triode and gassy. It's
nice to look at anyway.

Raymond

[Raymond Koonce]

Alan Douglas wrote:
All I can guess is that someone used a dud tube to test the
hot-stamping dies. The longer name looks vaguely familiar
("Commander" first came to mind which was a Chicago maker I think).

Alan

Thanks for your input Alan.

[ian field]

"Brenda Ann" wrote in message
...

"Peter Dettmann" wrote in message
...
On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann

Voltage regulator, maybe?

Thyratron?

[Paul P[_2_]]

"ian field" wrote in message
...

"Brenda Ann" wrote in message
...

"Peter Dettmann" wrote in message
...
On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann

Voltage regulator, maybe?

Thyratron?

formerly used at ALCOA for the electric furnaces....... ;~)