The Talking Machine Forum — For All Antique Phonographs & Recordings

Can someone tell me what capacitors to use as replacements in the capacitor bank. The 1Mfd cap is shorted. Thanks

The attached PDF will answer you question. It is a fun job changing out those caps in that can. I have done it many times though.

Why deal with all that black goop inside the can, isn't there enough room in the chassis outside the can for a modern type ?
Or better yet, just add a terminal strip and replace them all if you have the room.

electrolaman 64 wrote: Sat Feb 10, 2024 12:38 am The attached PDF will answer you question. It is a fun job changing out those caps in that can. I have done it many times though.

VTMC Service Bulletin 777C amp 1928.pdf

Thanks for the info Carlton. Do you use a regular electrolytic or a nonpolar and what voltage?

Do not use electrolytic.
I use 660VAC rated motor run (not start) and keep the values the same.
660 vac rating is good for 1000V plus.
I have done about 30 of these and they are going strong 45 years plus

Do not use electrolytic. Here is more information with regard to buying caps for the 700 series amp. Same voltage ranges for the caps apply in both the 736 and 777C amps. Photos of my Capacitor restoration..... doing it the neat way. Note: the capacitors are in wax not tar as someone else inferred. Much easier to melt out.




Carlton

Here is additional information for the AP-777-C amplifier with capacitor voltages and current Mouser part numbers.