Type 488 tube
 

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

Type 488 tube
 

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

Alan

Type 488 tube
 

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

Type 488 tube
 

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

Type 488 tube
 

"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?

Type 488 tube
 

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

Type 488 tube
 

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

Type 488 tube
 

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.

Type 488 tube
 

"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?

Type 488 tube
 

"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....... ;~)