Arvin 4080T 8" Table Set

[Kevin Kuehn]

I found this lonely little set at the local thrift store yesterday afternoon. It's not beat up too bad, but unfortunately it's missing its back cover, along with the on/volume and fine-tuning knobs. Also the center of the channel change knob has what appears to be paint splatter all over it, very strange

The connector on the crt is loose, but the filament does light. I'm not even sure if an 8AP4 can be tested for emission on my B&K 466? I guess as it stands it's a nice parts set. Possibly someone has the missing parts? or even needs a better cabinet for theirs. I'm open to all suggestions.

[Eric H]

Cool, I'd like to find one of those at a Thrift Store!

The CRT should test on your 466, same settings as every other 40's tube, 10BP4 12LP4 etc.

Someone surely has a back, there are so many of these all beat to heck, this one looks restorable.

[Kevin Kuehn]

Originally Posted by Eric H

The CRT should test on your 466, same settings as every other 40's tube, 10BP4 12LP4 etc.

Eric, I can test for H-K and G1 leakage, but how do I set G2 cutoff voltage?
As far as I know an 8AP4 has no G2

[Kevin Kuehn]

Curiosity got the better of me, so I had to take a little peek under the chassis. Overall pretty clean, and looks like it should be easy to recap. I found the SAMS folder over on ETF. Boy it's hard to resist working on the latest and greatest treasure.

[Phil Nelson]

Great score. A compact set with lots of eye appeal.

Looks like the tuner uses air variable capacitors, similar to the Pilot TV-37 or this one in my Capehart-Farnsworth 661-P:



I'd be tempted to start recapping, too. Is that an unobtanium CRT?

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[jr_tech]

Originally Posted by Phil Nelson

I'd be tempted to start recapping, too. Is that an unobtanium CRT ?

Quite likely very difficult! Years ago, I had a beige colored model of the same set with no knobs, no back, rust on the chassis and a slightly off-color repaint job (the beige was somewhat pinkish) however, the set worked well, with mostly original parts... another collector wanted it badly, but I did not want to trade/sell it because the tube was so unique. He quickly found me a gassy "dud" that I use for "show and tell" to this day. He indicated that gassy ones were pretty easy to find. Not a good sign!
Hope your CRT turns out to be good!

jr

[Kevin Kuehn]

Hi Phil,

This tuner is a little different.

Google shows one NIB 8AP4 sold on ebay this past summer, so apparently they're not unobtainium. On the other hand I'm not too sure they were used in many sets. This is the first 8" I've ever run across. I expect a dozen complete TV's will surface before a crt only.

[Zenith26kc20]

I have to say, that tuner is wild looking! That appears as a metal cone tube. Hope it's good as I want to see that little guy working!

[Eric H]

Originally Posted by Kevin Kuehn

Eric, I can test for H-K and G1 leakage, but how do I set G2 cutoff voltage?
As far as I know an 8AP4 has no G2

Hmm, well in that case I don't know, does your 466 have the setup instructions?
If not I have them and could look it up.

[Kevin Kuehn]

Originally Posted by Eric H

Hmm, well in that case I don't know, does your 466 have the setup instructions?
If not I have them and could look it up.

My tube chart lists the 8AP4, but there are no specific set up instructions per say. It only lists to plug into socket 1, which is the standard socket on the 466 cable. The problem is there is no way to set the g2 cutoff voltage, and no switches to program it otherwise. So I assume the test is only valid for heater to cathode and g1 leakage.

[Eric H]

Originally Posted by Kevin Kuehn

My tube chart lists the 8AP4, but there are no specific set up instructions per say. It only lists to plug into socket 1, which is the standard socket on the 466 cable. The problem is there is no way to set the g2 cutoff voltage, and no switches to program it otherwise. So I assume the test is only valid for heater to cathode and g1 leakage.

I had to look up a pdf on the 8AP4 to understand what you meant, I see now where a 10BP4 has G2 on pin 10 the 8AP4 has no connection on pin 10, I was assuming it used the same gun

It shows G2 as being connected to the 2nd anode, which would be the shell of the tube in this case.

I don't know what to tell you at this point, perhaps just try and test it omitting the G2 adjustment and see if that works, or maybe you could connect the anode to pin 10?

[Eric H]

Originally Posted by Phil Nelson

Great score. A compact set with lots of eye appeal.

Looks like the tuner uses air variable capacitors, similar to the Pilot TV-37 or this one in my Capehart-Farnsworth 661-P:

Phil, I have a set that uses this same, or very similar tuner with the plates.
I can't remember which one it is for sure, maybe the Sonora?
The Raytheons with the variable tuner use slugs.

[Eric H]

BTW, that looks like a very clean chassis, I would do everything possible to restore this set!

I'd recap the chassis enough to get the HV and sweep working and find out how good the crt is, looks like it has all of 10 or 12 paper caps!
Check the getter on the CRT first though to make sure it hasn't gone white.

Generally the smaller metal tubes don't seem to have leakage problems as much as their bigger siblings.