"At 11:38pm on March 25, 2024, David C. Poland said…
Again, if the hi=lo switch is missing, use a meter to determine which primary post is for the higher mains voltage. you should have 3 lugs for the power transformer primary. Probably…"
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Help needed
Started this discussion. Last reply by David C. Poland Mar 25. 21 Replies 0 Likes
Working on all wave 15, no sound or reception. Speaker rebuilt, everything good on speaker.Looking at schematic I see primary field coil only has 5 volts going to it, is this correct? all tubes are…Continue
all wave 15 question
Started this discussion. Last reply by Kent King Jan 8. 17 Replies 0 Likes
Happy new year to all, my first question is the volume control, i have a pictorial of the underside of the chassis, it shows the volume control to be a dual 500k volume and 700-ohm gain control. my…Continue
All wave 15 filament issue
Started this discussion. Last reply by David C. Poland Jan 1. 5 Replies 0 Likes
When reciever chassis is not connected I have 3 volts,once connected to reciever chassis, filament voltage drops to 2 volts ,I see no filaments lit.Any suggestions as to where to look?Continue
Scott all wave 15
Started this discussion. Last reply by douglas wright Dec 31. 13 Replies 0 Likes
i am needing help getting parts for a allwave 15 in a Warrington cabinet.i am needing the dial escutcheon and all the escutcheons on the front panel.i would be happy to begin with obtaining a dial…Continue
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"Again, if the hi=lo switch is missing, use a meter to determine which primary post is for the higher mains voltage. you should have 3 lugs for the power transformer primary. Probably can't tell with resistance measurement of the…"
"If you have not tried a new 5Z3, do so. An old tube may be suspect. Did it test ok earlier.
You have a proper size fuse? fuse did not blow?
Also, was the amp right side up when you powered it?
If on its side, orient the amp so pins 1 & 4 are…"
"17113359616581633919601195299621.jpg"
"Kent,
The tube will start arcing, then the filaments will go out.
Test the tube and tube is dead.
I think I measured 5.2 volts at 5z3 filaments."
"My transformer is tapped, 115 or 120.
Not sure how to post photo on reply.
My transformer looks original"
"Even with the higher line voltage elevating the B+, 470 volts is a bit much. Initial surge likely even higher hitting the 1st Filter cap ahead of the 30 Henry choke the hardest.
You figure why no hi-lo switch? do you have power transformer with tap…"
"What do you meaning by losing the 5Z3 filament? Does the tube go bad (filament open)? Or something else? Does the set blow the fuse? Be sure you are using no more than a 3A fast blow fuse.
Kent"
"Kent. I am measuring 480 volts, with 125volt input line voltage, I also seem to be losing the 5z3 filaments not right away, just when it has been on for about 30 minutes while I am trying to measure voltages inside set.
I will have to check why this…"
"I don't recall the exact voltage but it will be very high, as there is a significant drop across the rectifier tube and the filtering...probably 450 VAC...and BE CAREFUL measuring those voltages - they are AC, more dangerous than even the high…"
"One more question for you guys and then I won't bother you for a while.
What should the plate voltage be at the rectifier plates from the transformer.?"
"Just to be sure, the correct 3 tube power supply uses 5Z3 and two 2A3 outputs. Sockets have tube numbers embossed.
The hi-lo switch is for the primary of the power transformer, to deal with the era's fluctuations of house voltages.
Is you…"
"My 15 is the later with the 55 2nd detector.
Also my power supply differs from the schematic, it does not have the hi/ low switch. It also doesn't have the 2 bath tub caps on the side of chassis. The cam I mentioned is in the antenna coil…"
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Comment Wall (1 comment)
- At 11:38pm on March 25, 2024,
David C. Poland said…
Again, if the hi=lo switch is missing, use a meter to determine which primary post is for the higher mains voltage. you should have 3 lugs for the power transformer primary. Probably can't tell with resistance measurement of the primary.
photo MG_1056.jpeg of my AW-15 transformer primary lugs for reference. Notice the partly obscured 110 and 120 labeling.
So REMOVE the rectifier tube. Then move the power cord connection between the two primary lugs and see which give you the LOWER voltage measured between the high voltage center tap and one of the tube socket rectifier plates. use the 500 volt AC scale. Maybe put one hand in your pocket for safety when you power on. You are seeking the one that shows a LOWER high voltage.
While you are at it, double the measured voltage to see about what your first filter cap is seeing as a full wave output. CAUTION: With the rectifier tube inserted, the speaker and receiver absolutely need to be plugged into the amp to draw down the working high voltage somewhat.
If you are inadvertently feeding 125 volts AC into the "lo' side, the B+ voltage will be way high.
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