[davidff]

I Recently found a "spare" chassis for a  41/623 Radio/BOL .  I recently restored a complete unit and thought it would be a good idea to have a spare for parts, etc.    I replaced the rotted out power cord, and all the electrolytics.  and now  It powers up all the tube filaments  but the 50Y3 rectifier will not power up.  I know the tube is fine as it works in my original good working  chassis.  I am seeking some advice on how to proceed.  I would like to get this chassis working if possible.  The transformer does not "appear" to be shorted as far a leaking, etc.   Thanks for reading.

[morzh]

David


It should be easy.

Simply (if you DO know the tube works) check
1. The transformer's winding that feeds the rect filament
2. Wiring to its socket
3. Socket itself for contact/oxidation.

Likely is one of these.


PS. If it is 41-623 it has no transformer.....or what is it you are referring to?
http://www.nostalgiaair.org/PagesByModel...013445.pdf

[klondike98]

The 41-623 is an AC/DC set and has no power transformer and the 50Y6 rectifier filaments are in series with 3 of the other tubes so they should not be lit either if the rectifer filaments or socket are causing and open, or am I missing something?

[morzh]

Yep. My question exactly.

[davidff]

One of the 7B7 tube wont light and the XXD will not light.(both test good)   The other filaments, (not the 50Y6) all lite as well as the pilot lamp.  I will spray the tube sockets with deoxit and wiggle a bit.  I do not see any broken wires underneath.

[klondike98]

OK, there has to be something causing an open in the filament series.  As morzh suggests try cleaning the tube sockets and I'd also resolder each of those connections in that series; perhaps there is a cold solder joint causing the problem.  

[morzh]

There is also 50L6GT tube in series, have you checked it? It cannot be lit either.
In any case, why don't you look in the sch and follow it. Wiggling/sprying is only good when you know what you wiggle, spray, tap, and why.

[davidff]

That 50L6 was the guilty one.  I did not see that the filament was bad, I cleaned all the pins, and with a replacement, I now have all tubes lit.  I just need to connect it to the speaker and see how it performs.  Thanks for the guidance.