Dumont RA-110 from ETF
 

Managed to get this set in the silent auction for $20 :)


The bad news: 19AP4 is toast

The good news: Cabinet has had a decent amateur refinish job and the knobs were sitting inside a coffee cup tucked between the picture tube and chassis.....but that's not all!

After giving the chassis a once over, I'm convinced this was a working set that had a picture tube failure. The recap job here is artistry. Whoever did this job used some funky 2 x 50 uF 500V UK manufactured caps and mounted them neatly in the chassis. Not really any info out there on them, they say FAC/RD37DUK 95-42.

They make everything look so neat, in the midst of what would be long terminal strips of caps mounted on the chassis if I were the one doing the job. Even the disc caps are all new.

Also, there's a funky relay underneath, with one wire labeled COIL. A quick glance shows that the wires go between the power transformer and the twin 5U4s. Could be some type of surge surpression that someone built in, like a soft start circuit?

Anyway, I'd love to shake the hand of the man who did this work.....

:thmbsp: I'm just about 99% positive that you will find that relay is a "field repair" replacement of a Dumont factory supplied item .

I'm less sure as to it's exact functioning , but my guess is that it was to protect the CRT from being phosphor burned in the event of a sweep failure ?

I don't have a schematic to be able to say. I just can't recall ever seeing anything like this in any set I've ever had my hands in.....

The relay was standard fare for Dumont/Crosley sets. 5000 ohm coil.
Usually bad and often just bypassed. 6AL5 activated. I recently replaced
two.

WIll it not wake up at all? On say 8-9 volts--will is give decent emission--or is it just "dead"?

The RA-110 manual is on our site.

Those are guitar amplifier filter caps... manufacture stopped around 2001 or so, but they were common in Marshall and other british made tube amps.

So, what is that tube mounted underneath the chassis?

That's the odd thing. Powered it up on my tester, 6.3V, and let it warm up for a minute. Walked away for a sec, heard a quiet SNAP, and the filament went dead :(

Never had that happen before.

Thanks Steve, I was actually reviewing the DuMont service notes and find it odd that they claim that the RA-110 and RA-103 chassis are basically the same, especially since the RA-110 has a separate HV chassis. But since I've never had my hands into an RA-103 before, I can't really say.

It's a 6AL5....

Sorry to hear, that is typical heater burn-out for a very gassy tube... likely the 19AP4 was pretty much "up to air" when you got it. How do the getters look?

jr

I have the same set in blonde. I picked mine up on Ebay for $10 and like yours had a dud crt. I picked up a tested like new crt for $75. The set was recapped in the recent past so I tried it and it works well except that it needs a new focus control. The winding of the control is burnt in the "sweet" spot so I cant get the raster as sharp as it could be.

crt
 

I have a crt if you decide to keep it.

Oh, I'm keeping it, believe me :D

Might have one lined up, but if not I'll definitely let you know :)