I recently acquired a Philips Cd 204 I'm in the process of restoring to full working conditions. So far I have fixed the tray (gear and belt broken), replaced all caps in the PSU (actually old Nichicon's were perfectly fine), replaced all low quality Philips caps in all boards but the CDM-1.
I have one last problem to fix, the headphone amplifier: if I connect it to the other boards, RCA output is distorted and headphone output is severely distorted; if I unplug it, RCA output is perfectly fine.
Schematic is attached, it is a simple 1x buffer feeded directly by the RCA output; I checked the cable and it is fine, voltages are fine, caps are new and resistors are not shorted. Only remaining option is a faulty op-amp: it is actually a NJM4560 not a NJM4556, but anyway it appears to be a pretty standard headphone amplifier of those days. Is it a common failure ? Do you have any suggestion for a modern replacement ?
I do not plan to use it (fixed volume is useless) but anyway I would like to fix it.
Thanks
I have one last problem to fix, the headphone amplifier: if I connect it to the other boards, RCA output is distorted and headphone output is severely distorted; if I unplug it, RCA output is perfectly fine.
Schematic is attached, it is a simple 1x buffer feeded directly by the RCA output; I checked the cable and it is fine, voltages are fine, caps are new and resistors are not shorted. Only remaining option is a faulty op-amp: it is actually a NJM4560 not a NJM4556, but anyway it appears to be a pretty standard headphone amplifier of those days. Is it a common failure ? Do you have any suggestion for a modern replacement ?
I do not plan to use it (fixed volume is useless) but anyway I would like to fix it.
Thanks