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Luke 11th December 2005 07:53 AM

troubleshooting philips cd650
 
I screwed up and have broken my cd player.
I changed some caps, and removed the output caps, reclocked it and put chokes in the supply lines.
As far as I can see I made two mistakes neither of which should have damaged the player.
The tda1541 -15V rail cap was back to front, I replaced it and the tda1541.
I also forgot to turn the power supply for the clock on (its still not permanently installed) So the thing was spinning like crazy for a couple of minutes untill I realised all was not well.
After I rectified the mistakes the player seems to track fine, but there is absolutely no output. Any ideas how to trouble shoot this fault?
I have a schematic BTW and a scope.

thanks Arthur

ash_dac 11th December 2005 09:09 AM

Quote:

I changed some caps, and removed the output caps, reclocked it and put chokes in the supply lines.
Hi,

Please explain what you meant by 'removed the output caps'

I'm guessing it had NE5532 output amp's. :xeye:


Kind regards,

Ashley.

Luke 11th December 2005 09:18 AM

Quote:

Please explain what you meant by 'removed the output caps'
Its a mod I did on my marrantz cd67 as per Kuei's instructions.
Its a dc blocking or coupling cap from the output of the opamps to the mute transistors I think. they are 220uF 10V caps and I replaced them with a piece of wire.

ash_dac 11th December 2005 09:37 AM

Luke,

Have you tried your amp with a different source?


Kind regards,

Ashley.

Luke 11th December 2005 09:40 AM

Quote:

Have you tried your amp with a different source?
Yes I have. And it works, so Im sure something aint right with my cd player:whazzat:

guido 11th December 2005 03:36 PM

Do you have output on the 'filtered' output?
If not, take out the wire that replaced the 220u cap and try again.

As for removing those 220u caps: that is possible in the 63/67 because the offset is minimal. Did you measure the offset before you did the mod?

Guido

Luke 15th December 2005 05:56 AM

Hi Guido.

I put the caps back and still nothing. Something that didnt seem right was the cap across pin pin 13 and 24 on saa7220p/A is only 3.3V and not 5. Is this ok?

guido 15th December 2005 09:04 PM

Not really, that's a +5V supply cap. So maybe it's toast.
Use that scope to see if there is anything going on on the I2S lines towards the 7220 and towards the 1541.

Luke 15th December 2005 10:10 PM

thats what I thought. If its toast is it worth trying to fix?
I would think these parts are almost impossible to get now?

guido 16th December 2005 10:47 AM

I meant the cap, not the 7220:D You say you have a scope: start measuring!


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