[dconant]

Hello, I got this Philco 611 for free. I did not realize it was an AC/DC set until I started to look at it wondering where the power transformer was. Guess what there isn't one you big dummy. Checked the tubes and found the 6 volt ones had open filaments so what happened there? The 43 and 25Z5 are good. I thought about just using this radio for parts as the cabinet is pretty beat up. I want to see if it plays so I tacked in replacement ecaps cutting out the old ones and replaced the dead tubes. Bought it up slowly. There is not a peep out of it. All parts of the speaker are good. I started to check voltages and noted at most 12 volts from chassis to what ever. So I tried cathode to plate on 25Z5 and get about 117 volts. So this makes me wonder how do I read the voltages on the other tubes as in where do I connect the negative probe?  

Yeah I know its a waste of time to troubleshoot a radio with original caps. I just want experiment a bit. At least get the audio amp doing something.

Dan

[morzh]

The AV plug's pin that is not the one going to the 25Z5 Anodes is the B-.
Measure towards i to know the rest of the voltages, unless specifically noted in the sch.


611 is the 610 with AC/DC power.

[Arran]

So all of the 6.3 volt tubes had open heaters? I have a 32 volt set where someone plugged it into the 120 volt mains and the way they worked it was that the 6.3 volt tube were in series across the 32 volts, but only one had the heater/filament blown open, one was still all right, and the other had poor emission, so one would think that the Philco 611 would have behaved the same, the weakest one would act like a fuse and pop before the other two? The 25 volt tubes have heavier heaters so no issue there, although in my 32 volt set they were connected across the 32 volt line, so they died with having 120 volts across them.
Regards
Arran

[dconant]

Yep all three. The 6A7, 75 and 78. All 5 tubes are in series. There is a canned ohm to take care of the rest of the volts.

[Arran]

I'm wondering if someone may have pulled the trick of pulling the original tubes and putting duds in there, are they Philco brand tubes or something else?
I rather like the looks of that set, if it's the tombstone version, I have a 620 which is similar, a good set if you can get one.
Regards
Arran

[dconant]

Arran, I thought about the tube swap. Two are Philcos and the other is Tung Sol. I have a 620 waiting it's turn.

Dan

[dconant]

I see why at least one of the 6 volt tubes burned out. While the input voltage is at 105 volts the 6 volt tubes are at 6.2 volts and the 25 volt tubes are at 21 volts. The tubes are all .3 amps. The canned ohm is reading pretty much spot on so why are the 6 volt tubes getting so much voltage?

Also when I do DC checks I am getting over 80 volts no matter where I probe in the radio even on the volume control connections. I'm using the AC line where the one wire is not connected to the 25Z5 tube for the negative point. Why is this? Have I misunderstood what Mike said earlier? Frankly I don't get this radio. I've started on this so now I want to see it working.

[morzh]

6V tubes are actually 6.3V tubes.

And some variation of that voltage, whether less or more, are actually normal. You do not have anything you should worry about.
And you could bring the voltage to 115VAC which is what is expected.