CDM-4/19 running at warpspeed
 

Hi,

the CDM-4/19 of my Philips CD780/00R player runs at warm speed when I turn on the power switch of the player. Since I don´t have any service manual neither of the player itself nor of the CDM-4/19, can anybody here please advise where and how to start debugging?

Thanks a mil in advance!
P.

Philips
 

Hi P,


If there is a SAA7220 or a SAA7345 in the player, than probably this is the culprit of the spinning CD.


Best regards,


Audiofanatic ;)

Hi there,

there is a SAA7220P/A and a SAA7210P in the player... . How to best diagnose whether the SAA7220P/A is the culprit one for the warp speed? I mean, I have just the datasheet of the SAA7220 in front of me and am looking for best practice diagnosis.

Thanks a mil again,
P.

From my digital guru:

"Tell this guy to check the '7220 for proper operation. It has the clock,
and if that chip does not work, the platter spins at warp speed."

Look first at the TCA0372. If this are blown/shorted the CD will spin non stop.

Check ALL supplies first to all I/C,s. Might be a safety resistor gone high.

@Mooly: All supplies to all ICs look good. I am just done with measuring. Even all resistors look OK to me.

@Predator864: There is a TCA0372DP2 (Motorola) on the board. I even have the datasheet and started measuring. Hmm.. question: Would the CD spin counter-clockwise at overspeed when this TCA0372DP2 is blown/shorted?

@SY: The SAA7220 is absolutely OK from what I measured. And the SAA7110 shows a fixed 88.19 kHz signal on Pin 17 (MSC). This is good news, right?

@All: If anybody could share the Service Manual for the Philips CD780/00R with me, I could continue much more systematically. Your help is highly appreciated!

Any more hints on how to continue a bit more systematically? I would like to track down the 88.19 kHz signal from Pin 17 (MSC) of the SAA7220 a bit further, but I don´t have any schematic of the PCB of the CD player, so I am a bit lost at this moment. :xeye: Any advice you could give, please?

I blown a TCA0372 while measuring it. Then the CD began spinning like a madman.

@Predator864: Did the CD start spinning counter-clockwise after the TCA0372 was blown?

I dont know. Scared the crap out of me and unplugged it immediately.
I can clearly remember by shorting two pins of the IC the CD would spin in a direction, but again I dont know if it is CW or CCW.