Measured the HFIN pin on TDA8808T and the voltage was 0,7. This is half of the typical value in the datasheet.
Out of ideeas.
Out of ideeas.
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.
Hi there,
Well, I can see a faint red, not very bright, not disturbing to my eye. The 100mV is when the laser in activated.
All the Voltages are OK.
+/-15V, +/- 10V, +/-~5V.
Didnt check the ~1 and ~2. Cant figure where.
Well, I can see a faint red, not very bright, not disturbing to my eye. The 100mV is when the laser in activated.
All the Voltages are OK.
+/-15V, +/- 10V, +/-~5V.
Didnt check the ~1 and ~2. Cant figure where.
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.
The 50mV value is stable all of the time ?
Cause mine, when the laser is on, varies from 34-56.
Changed the 4 rectifier diodes from the tray motor, still no result.
Cause mine, when the laser is on, varies from 34-56.
Changed the 4 rectifier diodes from the tray motor, still no result.
My 50mV varied as well. Between 45 and 55 mV. Also depending on a homeburned CD or a bought "silver" one. The homebrewed was lower in mV.
Thank you.
Another problem solved.
I have an option for troubleshooting. To test the exact voltages in the CD-480 and compare to the Marantz. Half of the Philips is aprox the same (the last part is the decoder: 7310)
Another problem solved.
I have an option for troubleshooting. To test the exact voltages in the CD-480 and compare to the Marantz. Half of the Philips is aprox the same (the last part is the decoder: 7310)
Discovered that the -15V rail is actually -10V rail wihile the unregulated voltage is OK (23V).
The voltage for the front pcb is only -15V, and input of 21V (7815 regulator) where i should have 32 input and 27 output.
The voltage for the front pcb is only -15V, and input of 21V (7815 regulator) where i should have 32 input and 27 output.
This last reply from you was very confusing 
-15V from a 7815 reg. ?? Isn't it a 7915? And shouldn't you have -15 V out from that?
+32V in to the same regulator and +27 out ??
To much beer? 😀
-15V from a 7815 reg. ?? Isn't it a 7915? And shouldn't you have -15 V out from that?
+32V in to the same regulator and +27 out ??
To much beer? 😀
Nah.
Today I was a volunteer. Lots of work.
Well, the -15V regulator outputs -10V instead of -15V. At the input the voltage is normal (23V).
And the 6647 (part number on schematic) regulator ( for front PCB) at the Input has a Voltage of 21V and at the output 15V, where I should have 22V.
Today I was a volunteer. Lots of work.
Well, the -15V regulator outputs -10V instead of -15V. At the input the voltage is normal (23V).
And the 6647 (part number on schematic) regulator ( for front PCB) at the Input has a Voltage of 21V and at the output 15V, where I should have 22V.
Well I will disappoint you, but my CDM doesnt have anykind of rubber.
It slams pretty hard. This is unusual.
It slams pretty hard. This is unusual.
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
CD-480 uses the small TDA1543.
It has a great potential. Changed 12 caps, decoupled the decoder and the DAC. This simple mod yielded impressive results.
This players has the following:
TDA8808/TDA8809, SAA7310, SAA7220 😡, TDA1543.
Also it uses one TCA0372 while the Marantz has 2.
It has a great potential. Changed 12 caps, decoupled the decoder and the DAC. This simple mod yielded impressive results.
This players has the following:
TDA8808/TDA8809, SAA7310, SAA7220 😡, TDA1543.
Also it uses one TCA0372 while the Marantz has 2.
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
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