Sorry, I haven't answered lately, but I have to much going on and very little time.
Yes, if you have another working unit, with the same CDM4 reader, it could maybe give you an answer if your reader is "kaputt" or not.
If you have 100mV at the laseramplifier, which is to much, it should give some light. Can you see any faint red light when you press play?
Does this 100mV change in value when you adjust the laseramp?
About the rectifier diodes, you said it yourself, Changed diodes, bang, the player is dead.
Could you have done anything wrong at that moment? Look around at the solderings with a strong light an try to find something that could have happened when you did the diodechange.
Also look at every voltage that should be on the motherboard that it's present.
Sorry, I can't help you more. But don't give up until you have found what was wrong. If you have another player to compare with and measure it would be great.
Yes, if you have another working unit, with the same CDM4 reader, it could maybe give you an answer if your reader is "kaputt" or not.
If you have 100mV at the laseramplifier, which is to much, it should give some light. Can you see any faint red light when you press play?
Does this 100mV change in value when you adjust the laseramp?
About the rectifier diodes, you said it yourself, Changed diodes, bang, the player is dead.
Could you have done anything wrong at that moment? Look around at the solderings with a strong light an try to find something that could have happened when you did the diodechange.
Also look at every voltage that should be on the motherboard that it's present.
Sorry, I can't help you more. But don't give up until you have found what was wrong. If you have another player to compare with and measure it would be great.
Adjusted the laser pot to 0.05-0.06 ohms. Now the laser when it`s on, osscilates between 32-52mV.
The next good thing, is that the cd is spining more often.
But in the end, same error.
Maybe the laser is worn out.
I can buy several Philips CD Players with CDM4 in, at about 30 Euros a piece.
I have an offer for the Grundig CD-35 ( Marantz CD-25) with CDM2 and 2xTDA1540 at about 40 Euros. What should I do ?
The next good thing, is that the cd is spining more often.
But in the end, same error.
Maybe the laser is worn out.
I can buy several Philips CD Players with CDM4 in, at about 30 Euros a piece.
I have an offer for the Grundig CD-35 ( Marantz CD-25) with CDM2 and 2xTDA1540 at about 40 Euros. What should I do ?
Despite the pesimism, the CDM4 is HEALTHY!!! 
Thank you God.
Now is working in my Philips CD480.
That concludes that the problem is somewhere else.
Can someone help me measure the 22k Pot voltage ?
And where should I measure the ~1 and ~2 ? At the rectifier anode and transformer EARTH ?
I need a guide to point me the next step.
Thank you God.
Now is working in my Philips CD480.
That concludes that the problem is somewhere else.
Can someone help me measure the 22k Pot voltage ?
And where should I measure the ~1 and ~2 ? At the rectifier anode and transformer EARTH ?
I need a guide to point me the next step.
Hi there,
I`ve reasembled today the CDM. Measure point 27 with ground and set it to 400mV in idle when the laser isnt on. When it activates I have `bout 3,4V.
Now`s the funny part. Set the 4,7kO potentiometer to max resistance. Slowly reduced this until the disc platter was spinning. Measured the voltage, and surprinsingly the voltage across R3539 (R3501) was aprox 17-22mV. When set it to 50mV the platter is not spinning.
I`ve reasembled today the CDM. Measure point 27 with ground and set it to 400mV in idle when the laser isnt on. When it activates I have `bout 3,4V.
Now`s the funny part. Set the 4,7kO potentiometer to max resistance. Slowly reduced this until the disc platter was spinning. Measured the voltage, and surprinsingly the voltage across R3539 (R3501) was aprox 17-22mV. When set it to 50mV the platter is not spinning.
Predator, if your mech works in another player the inescapable conclusion is that you have done something wrong in your modifications.
If the CD480 is a TDA1541 player it can sound better than the CD42 anyway so I would cut my losses.
If you want to persevere then check if the CD480 is using 7210, 5708 and 5709 because these are predecessors to the 7310, 8808 and 8809 used in the CD42 and you should be able to work out what is wrong.
I am assuming you have measured the laser and focus settings when the mech is working in the CD480 and transferred these to the CD42.
As mentioned I would concentrate on the CD480.
sp
If the CD480 is a TDA1541 player it can sound better than the CD42 anyway so I would cut my losses.
If you want to persevere then check if the CD480 is using 7210, 5708 and 5709 because these are predecessors to the 7310, 8808 and 8809 used in the CD42 and you should be able to work out what is wrong.
I am assuming you have measured the laser and focus settings when the mech is working in the CD480 and transferred these to the CD42.
As mentioned I would concentrate on the CD480.
sp
Well the control chips are identical. I think half of one TCAO372 drives the tracking motor and the other half drives the focus motor. Not sure what the second TCAO372 in the CD42 does - perhaps half drives the spindle motor ???
Surely they are similar enough for you to cross check.
I can't comment on the TDA1543 (never heard one) but I have to say I am not a big fan of the SAA7350. See threads from the old Pink Triangle designer (sorry my mind has gone blank, it's John ........) for a different view.
sp
Surely they are similar enough for you to cross check.
I can't comment on the TDA1543 (never heard one) but I have to say I am not a big fan of the SAA7350. See threads from the old Pink Triangle designer (sorry my mind has gone blank, it's John ........) for a different view.
sp
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.