Low Battery constantly shown on Sony-D303 screen when powered

willitwork1

Hello Kaosun,
Seeking advice on a Sony-D303 Discman, have acquired one and played well for about 20 minutes until Low Battery showed up on screen. This message comes on all the time when powered on both from batteries (rechargeable and AA) but when power adapter is connected it shows No Disc and no orange light, both spindle motor and sled are non responsive.
Opened unit finding the 3 main smc (100mf 6v) capacitors leaked, so replaced these like for like.
Fault remains, any suggestions or advice?
Thanks

willitwork1

A quick update,

when replacing the 3 main SMC caps I noticed leak rot traces on the circuit board tracks, this around C331 and C338. A track leading to Q40 was broken which I fixed and behold the above fault is now repaired.
I have now ran into an new issue, there is no sound coming from the line out or headphone socket but I do get bitstream from the SPDIF port. This leads me to think another track is broken from the D/A converter to the headphone/line amp. Problem being, I downloaded a circuit diagram but see that possibly there have been several rev versions of this board? in the diagram I see IC301 but on my player I see two other chips and a crystal? Something tells me this fault lies around C531?

Any advice will be greatly appreciated.

kaosun

1: Replacing all leaking caps, clean all polluted area,
2: for all leaking rot area, remove all green solder mask to check whether the trace is broken? If yes, connect them.
3: No sound issue of Line out is quite rare, usually it's caused be leaking caps.
4: Low voltage alarm, pls follow the service manual to check DC-DC circuit voltage, +3.5V too low?
5: The service manual you downloaded from kaosuncd has two diagrams of D303 (DAC parts are different), pls browse to the end.
6: Pls lubricate your volume pot and replace your spindle motor.

surpriseone1

kaosun replied at 2023-08-01 11:34
1: Replacing all leaking caps, clean all polluted area,
2: for all leaking rot area, remove all gree ...

Thank you for the above advice, unfortunately this unit has several leak rot tracks which I could not accurately trace, so for the time being leaving to the side. Although in a few days time I will acquire my second Sony D303 so have a better Idea what to look out for on that one.  

kaosun

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