[RadioDR401]

Does anyone know if a power transformer for a model 87 will work in a model 86?  The schematics look almost the same.

[morzh]

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.....

[RadioDR401]

Thanks for catching this morzh.  I didn't dig deep enough and wrongly assumed the filament voltages would be the same.

[morzh]

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....

[Arran]

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

[RadioDR401]

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.

     

[Radioroslyn]

Sounds Great!