hello, i'll make this brief, i had my hands on a pretty good unit that worked smooth on reverse polarity but later realized after it started to smoke that i goofed up. Now with a correct polarity the play is slow or stops, rewind is slow, ff goes but then slows.. So now i need help.. PCB: 1-651-545-13
was a usb cord to barrel jack, i measured the voltage around 5v.. however i did the wrong polarity and burned the CX20084 chip, up until that point play, rr, ff was all working smooth and good. however, after it smoked and i fixed the polarity on the cord it was too late, now the play, ff, rw all are erratic.
sorry to say but you smoked a very hard to get and very expensive ic...do a search on Sony CX20084 (google / here on the forum) and you will find out that these are not available anymore and are being heavily faked on Ali etc.... There is even a seperate thread about adaptors/polarity on the 6C warning people about this before even plugging in a adaptor....even the wrong adaptor with correct voltage and polarity can destroy this ic. With these machines it is important to use the dedicated Sony adaptor for these machines to be absolutly sure you won't destroy it. Good luck with the repair.
A USB cord is likely to be a switch mode power supply. I have had at least 2 D6Cs in for repair which have had the CX20084 chips destroyed by switch mode power supplies. @Black Fingers some of the "6V" original Sony adaptors can deliver over 7V, which is too much for a CX20084. By far the safest option for powering a D6C is to use rechargeable AA batteries only. I recommend Eneloop Pros for this. Even a fresh set of alkaline batteries can deliver over 6V, which, I suspect, is too high for the CX20084.
It's really quite surprising that with this negative center pin requirement Sony did not include an adapter in the box for the WM-D6C. It was an optional extra. Same for the WM-D6 but at least a hybrid module can be repaired but with the D6C you have to find a CX20084 IC. I have similar issues with a D6C running slowly. Replaced CX20084 from a donor machine and it worked for a day and then back to the same problem despite only using batteries for power.
Can be frustrating finding intermittent faults. If it wasn't in near mint condition and an early Rev 1 D6C with the hyperbolic head I'd just relegate it to the spares box.
It may be worth checking C608. I had a SMD version D6C, which was running very slowly. C608, which should have been a 3.3uF tantalum, read 65uF out of circuit. Once I had replaced it the D6C ran very well.
Yes it's been replaced. More thought required on this one. There has to be a dry joint or cracked trail somewhere.
