Updates for any that is interested:
Changed the caps captured in below image:
- 1st row with 4 brown Silmic II 220uF/35V are the decoupling caps for preamp
- the 4 smaller Silmic II's 100uF/35V are the output capacitors for power supply
- the rest of them are Panasonic FMs 100uF/50V and 100uF/25V are use in bypass capacitors for accessory power supply and the microcontroller bypass ones
- the red Wima's are bypass film caps
View attachment 42314
Immediate results:
1. The volume is increasing more linearly . Previously the volume would increase too fast with volume know being rotated.
2. Sound - I can't feel too much of a difference, but bass seems more deep and accurate. Waiting a while for the caps to settle in (burn in as other would say).
Next step would be changing the resistors in preamp section, because while removing the board I could see that those resistors were being stressed and board got darker in that area. Also noted that the bypass 0.022 uF which I replaced with Wima, were almost cooked. They just broke into pieces when removed.
NOTE: As compared to the replaced caps on the amp boards, these caps were in specs. I have opened one and still could see electrolyte inside. But those on the amp boards were way off the specs, and ended on the dumpster.
Regards,
Claudiu M.