Pioneer CD player PD 802 problem Revisited Help

[colin.hepburn]

Hi All
OK I have decided to have another look at my pioneer PD-S801 CD Player
As I posted last time it developed a fault of a crackle and skip when playing mid way on the disc
I Talked to Dr John on the the phone about this he suggested some basic guide lines to try which I did but did not work so I gave up and put the cd player in the loft and forgot about it for some months

Last night I decided to have a try again with it and after powering it up it played no problem for about an hour or so then started to crackle and skip again with the foc locking up and unable to open the tray

I then powered it down and came back to it later and it worked fine again then same problem started up again

But with a hot plastic smell this time on further investigation I spotted one of two identical op amps
Was very hot

If the player was powered on but not playing a cd the op amps were ok putting my finger on the op amp and pressing play after about 5/10 second it got too hot to keep finger on it

This op-amp is one of two part number is LA6520
Anyone got any suggestion on this maybe Dr John could chime in here

Could it just be the op-amp that’s at fault or more like something up front of the opamp I believe this 3 way opamp is for the used as a motor & focus/tracking coil driver?

See schematic for CD Player and PDF for LA6520

[colin.hepburn]

anyone got any thoughts on what or why this LA6520 op-amp is over heating and shutting down on this CD player
unfortunately I don't have the test gear or the skills to test it so wondering if It is worth just replacing it while I can still get the op-amp
All thoughts are thanks welcome on this

[Phil Y]

Hello Colin,
I would say it could be the IC or equally well what it is driving. Really you could do with measuring the current from each output of the op-amp. It is, I think limited to 500mA per output so if one of the outputs is drawing that or more then you have your answer. Do you own a multi-meter ? You need to break the connection to each output in turn and put a meter in series on DC current range.
Alternatively if the feeds go through connectors you could just unplug them, if the chip still gets hot then it is probably at fault. Also, if the chip is getting that hot, if one of the motors being driven is faulty, that might be getting hot as well. Might be worth checking.

Phil.

[colin.hepburn]

Hi Phil
Thank you for your input on this
I will have a look at what you have suggested and see what I get
My knowledge on CD player is somewhat limited
When the player is power up but not in play mode the opamp is normal even when selecting other tracks so laser transport is working ok and searching the disc ok
When pressing the play button the player works fine but the opamp gets very hot in seconds then we get the crackle sound and track skip plus the display go’s off and the CD tray is locked closed until power down and left cool down then it will play again and repeat the above

[colin.hepburn]

Well it’s a strip down job to check the current of the LA6520 opamp so will look at this later
But I took some Voltage of the opamp
So fairly Close to the Plays Schematic apart from pin 4/5/6
When the player is in play mod sound is breaking up at the bass frequency
All the motor are ok
202 is the hot opamp

See image

[colin.hepburn]

Hi All
I have read online somewhere that some have replaced the caps on the board where the laser ribbons cable enters with successes on some models of players
But whether it world do anything with this player or not is another store but could try it and also replace the caps around the LA6520 opamp