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Echophone S-4 Help Wanted - Printable Version

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Echophone S-4 Help Wanted - Winky Dink - 01-16-2019

I have the set fully assembled, non-working, with a couple of issues impeding my progress.
 
[Image: https://farm8.staticflickr.com/7925/32882731378_0770cf940f_z.jpg]

 
The overriding issue is too-high voltage.  At 115VAC, the plate voltage for the 245 is over 300v, and over 700v for the rectifier.  So, I'm doing my testing now at 60v or 75v and all the other voltages seem higher than expected--except the filament voltages, which are all good.
 
[Image: https://farm8.staticflickr.com/7902/32882730148_a2576a31fa_h.jpg]
 
(Direct link to image:  https://flic.kr/p/S6JA4f)
 
Is the transformer putting out too much voltage, or is it likely that I have made some wiring mistake?  I've checked all the wiring several times, and it all seems OK except I'm uncertain about the RF transformers, but I'll ask about that later.
 
Thanks for looking,
Henry

RE: Echophone S-4 Help Wanted - Steve Davis - 01-16-2019

Henry, make sure you are using the high voltage tap on the power transformer.

Steve

RE: Echophone S-4 Help Wanted - Winky Dink - 01-17-2019

Steve,

I had the line connected to lug 81, 115V on the schematic.  I moved it to lug 82, 125V.  Is that what you meant?  At 115VAC, the 245 plate voltage was 345V.  Here's a full description of the transformer outputs at 60VAC, extrapolated to 120VAC.

[Image: https://farm5.staticflickr.com/4819/32897004678_0fc4126ded_c.jpg]

RE: Echophone S-4 Help Wanted - Steve Davis - 01-17-2019

Yes, the line should connect to 80 and 82. If connected to 81 all voltages will increase about 10 percent.

Steve

RE: Echophone S-4 Help Wanted - Winky Dink - 01-17-2019

Hm-m-m. Voltages did indeed increase, but the problem is that the B voltage is already too high. The 245 plate should be some between 150v and 250v. It's 345v at normal line voltage. Except for filament voltages, a quick check seemed to show all other tube voltages were too high as well.

RE: Echophone S-4 Help Wanted - Phlogiston - 01-17-2019

Are you testing this unloaded, that is, with one or more tubes removed?

RE: Echophone S-4 Help Wanted - Winky Dink - 01-17-2019

First let me say that I finally realize how the high-low voltage taps work--that is by changing the ratio between the primary and secondary. Before I couldn't see how going to the high voltage tap would decrease the transformer output.

I am testing with all tubes in. Fully loaded. But my test results have been so inconsistent that I switched to a different multimeter. The meter didn't make any difference. What I can see now is that when power is first on (Again, at 60VAC) the 245 plate voltage rises from zero to about 135 volts in a few seconds, then slowly reduces to 107 over a period of 2-3 minutes. I'm keeping it on now for 20 minutes to be sure that it stays at 107. If that stays steady, I check again at 115VAC, and if I get the expected 210v at the plate, then I'll proceed with the rest of the voltage tests, and if the radio still doesn't talk, then I go to my next issue.

That y'all so much.

RE: Echophone S-4 Help Wanted - Winky Dink - 01-21-2019

Further testing of the 245 plate voltage is more confusing (I keep checking the 245 because they're expensive and I'm afraid of killing it.)  At 60VAC, the plate voltage quickly rises to about 110, then over a few minutes it decreases.  After 20 minutes it's down to 70v.
 
BUT, when I ran it at 115VAC, the plate voltage started at 220v and over time, it increased until I stopped at 400v.
 
After reviewing all the wiring again, including the speaker and speaker plug connections, the only thing I'm unsure of is my wiring for the antenna coils, RF coils, and the potentiometer.  First question is, what kind of  RF coils do I have.  I've assumed that they're the original flavor--not the later models with Litz wire.
 
[Image: https://farm5.staticflickr.com/4880/32882730298_48c2c0d84f_c.jpg]
 
Of course, I have no idea what the descriptions mean.  With the connections I've made, here are the coil resistances.  Does it make sense?
 
[Image: https://farm8.staticflickr.com/7883/32882730168_11af43ce72_c.jpg]
 
One inconsistency is that I disconnected one of the Bakelite caps, and it isn't 50pF as indicated on the schematic.  If my cap tester is right, then it's less than 10pF.