08-20-2018, 12:49 PM
Russ +10
You don't want to use electrolytic caps in the power supply in these early AC sets. They where designed using large foil/paper caps. Small electrolytic caps can't handle the ripple current and will short after several months of operation. Use mylars instead. Also stick pretty close to the original capacitance value. By adding more it will cause the power supply output voltage to rise. Most are rated @ 630v which is fine.
A few yrs ago I was servicing a Philco 87. Replaced all of the faulty parts and used some 4.7mf@450v electrolytics in series to replace the 2mf or so caps in the p/s. All was well and the set was my go to set for abt 4 months till I was listening to it and the volume started to drop. Dropped down to nil. Took a quick look in the back and the 80 tube was lit a bright red (not good). Upon disassembly the input cap was a dead short. Replaced w/mylars has been fine since.
GL
You don't want to use electrolytic caps in the power supply in these early AC sets. They where designed using large foil/paper caps. Small electrolytic caps can't handle the ripple current and will short after several months of operation. Use mylars instead. Also stick pretty close to the original capacitance value. By adding more it will cause the power supply output voltage to rise. Most are rated @ 630v which is fine.
A few yrs ago I was servicing a Philco 87. Replaced all of the faulty parts and used some 4.7mf@450v electrolytics in series to replace the 2mf or so caps in the p/s. All was well and the set was my go to set for abt 4 months till I was listening to it and the volume started to drop. Dropped down to nil. Took a quick look in the back and the 80 tube was lit a bright red (not good). Upon disassembly the input cap was a dead short. Replaced w/mylars has been fine since.
GL
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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