03-05-2018, 03:25 PM
Does anyone know if a power transformer for a model 87 will work in a model 86? The schematics look almost the same.
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Dave Thomas
Coatesville, PA
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Philco 86 Pwr Trans
03-05-2018, 04:09 PM
Well.....philament voltage for 71A is 5V at 0.25A and for 45 is 2.5V at 1.5A, so the "C" winding is different. Otherwise it would work.....
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing. 
03-06-2018, 09:30 AM
Thanks for catching this morzh. I didn't dig deep enough and wrongly assumed the filament voltages would be the same.
*********** Dave Thomas Coatesville, PA
03-06-2018, 11:32 AM
Dave,
What sucks that for the most part they are the same  Except the Pus-Pull section. Then again, maybe you could fit the 45s into it instead of 71A Could require some mods.... People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
03-06-2018, 11:17 PM
The issue with the #45s is that they require more B+ voltage, and more bias I believe, I think you can use the same output transformer. It may be pretty close anyhow, the #45s run ar 2.5 volts but draw 1.5 amps, the 71As run at 5 volts but draw .25 amps, so the same winding with 1/6 the current draw. Are you sure that the original transformer has failed? Does it run hot, or smokes, or is open circuit?
Regards Arran
03-17-2018, 09:20 AM
It's definitely shot. It looks like someone attempted to "repair" it before me and literally toasted the PT. The good news is that I found a stripped down 86 chassis on eBay that still had the PT on it. I took a chance and bought it for $30 and after I rewired the primary and CT leads it worked like a charm. Reinstalling it will take a while but it looks like I'm back on business.
*********** Dave Thomas Coatesville, PA
03-17-2018, 10:18 AM
Sounds Great!
When my pals were reading comic books I was down in the basement in my dad's workshop. Perusing his Sam's Photofoacts Vol 1-50 admiring the old set and trying to figure out what all those squiggly meant. Circa 1966 Now I think I've got! Terry
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