Can anyone offer some suggestions why the machine does not play the disc after several power supply capacitor modifications?
This is what I have done so far
At first the player keeps ejecting the loading mechanism. I took that thing out and the player played CDs. I was very satisfied with the sound.
Then I turned off the player and screw everything back in place. I accidently installed a screw on the 22k focus trimmer so I replaced that with a piher 22k trimmer. Followed somewhere in other posts that I should adust the trimmer until the test point 27 to ground reads 400mV. I could not get any value close to that. My cheap DMM displays ~.005V, ~.006 at one point when I turn the trimmer.
Now "FTS" on the display keeps blinking. The player no longer plays CD, even when the CD tray is not in place. Did I kill the prescious CDM4?
Motor spins temporarily on start up. Arm locked in place after power on.. Seems like no laser beam though.🙁
This is what I have done so far
At first the player keeps ejecting the loading mechanism. I took that thing out and the player played CDs. I was very satisfied with the sound.
Then I turned off the player and screw everything back in place. I accidently installed a screw on the 22k focus trimmer so I replaced that with a piher 22k trimmer. Followed somewhere in other posts that I should adust the trimmer until the test point 27 to ground reads 400mV. I could not get any value close to that. My cheap DMM displays ~.005V, ~.006 at one point when I turn the trimmer.
Now "FTS" on the display keeps blinking. The player no longer plays CD, even when the CD tray is not in place. Did I kill the prescious CDM4?
Motor spins temporarily on start up. Arm locked in place after power on.. Seems like no laser beam though.🙁
did you use a anti-static wrist guard ?
Electro-static Discharge (ESD)
Laser Diodes are very sensitive to ESD and will fail if extreme care is not used in their handling. Common symptoms of laser degradation or failure are decreased laser output power, increased threshold current, or no lasing at all. Proper grounding is critical. Use static-controlled lab equipment and accessories when handling the diode laser at all times.
or any other part of the player
but im sure you did😉
Electro-static Discharge (ESD)
Laser Diodes are very sensitive to ESD and will fail if extreme care is not used in their handling. Common symptoms of laser degradation or failure are decreased laser output power, increased threshold current, or no lasing at all. Proper grounding is critical. Use static-controlled lab equipment and accessories when handling the diode laser at all times.
or any other part of the player
but im sure you did😉
Hi Karma,
I wore a ESD band before proceding to the mod. So I am not sure what went wrong. May be TDA8808/8809 chips are dying?
Now, somehow after an hour of messing around with the control buttons, I managed to make the player play CDs with the loading tray in place. The trick is to press the play button to close the cd mechanism, then press the same button again to make the CD player recognize the TOC. I don't have to do that before I mod the player.
Just don't know what's wrong with the player. The player plays fine now but the button pressing is very inconvenient!
The VFD is flashing like nuts while CDs are being played. Read from somewhere that the hard to find Telefunken chip caused all those problems.
I wore a ESD band before proceding to the mod. So I am not sure what went wrong. May be TDA8808/8809 chips are dying?
Now, somehow after an hour of messing around with the control buttons, I managed to make the player play CDs with the loading tray in place. The trick is to press the play button to close the cd mechanism, then press the same button again to make the CD player recognize the TOC. I don't have to do that before I mod the player.
Just don't know what's wrong with the player. The player plays fine now but the button pressing is very inconvenient!
The VFD is flashing like nuts while CDs are being played. Read from somewhere that the hard to find Telefunken chip caused all those problems.
Does the drawer switch work properly? It could be a solution to the problem that simple.
First search out the simple things, then look to more elaborate faults such as broken chips.
First search out the simple things, then look to more elaborate faults such as broken chips.
Thanks tubee. You are right. I forgot to put the white plastic part back to the mechanism so the drawer switch is left untouched. Now the player works 100% fine.
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