JVC videosphere

[Findm-Keepm]

There's a mod - you change C401 and C402 to a polystyrene/styroflex cap (originals are polyester/mylar film with a crappy TC...). Replace with 4700pF, 160V polystyrene, hard to find anymore. eBay would be the best bet. The old mylars (in the AFC circuit) would change value independent of each other and cause horizontal hold/frequency issues, usually double the H-osc freq.

I've used 4700 pf NP0 100V ceramics in a pinch - they are about 30 cents each and just as stable.

There's also an AGC mod, if I can find my photo-stat copy from the 80s - it's also a cap change from mylar to something more stable IIRC.

From my notes, also the 470uF/25V cap off the yoke (yoke return cap) will cause non-linearity issues. The only other note is about the Hfe on the vertical transistors - make sure any replacements have the correct Hfe code on the transistor, as linearity issues also erupt with the wrong Hfe group.