I just got one of these Panasonic SX units working, but I can't turn the awful S-XBS off without the remote. I've looked through the service manual and the furthest I've got is to trigger the reset test point. Unfortunately reset does nothing to the S-XBS as it is on by default... If anyone has a spare remote for one of these things, let me know! They should look like this: Alternatively, if anyone knows how to spoof the remote, that will be even better! The service manual does not include the remote's schematics.
Sorry can't help Bub, i avoid later panasonics like this for this reason, what a dreadful idea having the bass just on the remote
I will never recommend this series (2 Belt SX) either, due to its many problems (extremely fragile clutches and gears, rubber on capstans (!)) , weak amp. But part of my curiosity wants a working SX so that I can compare it to its Sony and Aiwa competitors from the same late years (I think that even with the S-XBS off, it's not competitive). I can finally get one of these things working thanks to Marian's new SX belts. Truly an awful design having some settings only on remote... but I like the white Panasonic reels.
I have both an SX97F and an SX87V. Same analog skeleton: AN7501, 100μF from the amp to the jack (C134 / C135), 22μF / 4V on the amp rail (C111), and an extra 1μF between the volume pot and the amp input (C51). Sony cassette portables do not put that 1μF there. What I changed on both: C134 / C135 → 220μF / 6.3V ceramic or tantalum C111 → 220μF / 6.3V ceramic on the same 1206 pads (stock is 22μF tantalum) C51 → 0Ω link On the 87V there is also C7 at 150μF / 2.5V; I treated that the same way and went to 220μF. After that the bottom octave holds when the volume is up, and S-XBS stops sounding like boosted empty water. The EQ was never the main problem — the path was already rolling off before it. I am copying the 220μF Sony used on CD/MD headphone outs, not adding more bass boost. Remote / S-XBS-off still needs the handset or a spoof. This is only the analog path.
