I have been reading this audio forum for a couple of years and I am really impressed with the knowledge and support the members are providing. I got a used Sony CPD-707ESD about 7 years ago and up to today it used to work fine. This is a really nice sounding CD and have been enjoying its performance in my system. Today I loaded the cd on the cd tray and it closed without any issues. Then the display was showing DISC & MEMO and it did not play the CD. I tried several times by opening/closing the cd tray and it did not play. I opened the top cover and observed that the cd tray was functioning properly by closing the tray and lowering the chucking arm. Then the CD did not start spinning. I checked the motor connector and could not see anything wrong with it. Please let me know how to go about troubleshooting this issue, your help is really appreciated.
Hi ManoloMos and thank you for your quick note. I checked the lens and this is what I observed. When the CD player power button is turned ON the lens moves al the way to the front, then moves back about m3-4m and then moves back all the way to the front (towards the center of the CD) and then moves back about 3-4 mm. Then the lens stops moving. When the tray opens and closes the lens goes through the same movements.
Are the movement of the lens correct to try to read the CD? Thanks.
Are the movement of the lens correct to try to read the CD? Thanks.
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Hi. For to see the health of the laser diode, first locate R102. This resistance is 22 ohm. Then, take a voltmeter, and measure the voltage in R102 the moment when the cd is trying to read. Then, with the ohm law, V=I.R, figure out how much current is over R102. It should be betwen 50 or 70mA. If it is over 100mA, the laser is dead.
Don't throw the laser pickup to the dump bin, I'm trying to do replace the laser diode in KSS-151A and KSS-190A. When I got success, with this, I'll publish a tutorial in this forum.
Best regards
Don't throw the laser pickup to the dump bin, I'm trying to do replace the laser diode in KSS-151A and KSS-190A. When I got success, with this, I'll publish a tutorial in this forum.
Best regards
Hi, I located R102 and measured the voltage when the cd is trying to read which was 1.21 VDC. Based on V=I.R, the current was 55mA. I also managed to see a little red laser beam although it was difficult to see. This means that the laser diode is in good shape and I will continue the troubleshooting to find out why the motor is not spinning.
Best regards
Best regards
Hello. Maybe is ok, or maybe power has decreased. 55mA is a good value, but I think is low. Well, look to the laser pickup, and look for the label where it says KSS-190a or whatever. There are few numbers. Look the line with three numbers, this shows the laser current adjusted at factory, for example 627 is 62.7ma.
Tell us what it says. Regards
Tell us what it says. Regards
Hi, the initial sequence is this:
1.- Close the door and the optical block moves to the initial position, it goes to the next step:
2.- Turn on the laser, for this, pin 5 (LD) of IC101 sends the turn-on signal to Q101, note that it is PNP, so in the base it must have 4.4V, this makes the laser turn on, it must so that you (with a small mirror) can see it clearly.
3.- Then the lens will go up and down two or three times looking to focus on the reflection of the laser beam, and when this occurs it will change the state of focus ok (pin28) and go to the next step:
4.- The rotation of the disk starts (spinle motor)
You must check if it has the 4.4V at the base of Q101, if the current is correct in R102, and if the signal is produced on focus ok (pin 28). If not, I would think about replacing the KSS-190A laser unit if the player deserves it.
1.- Close the door and the optical block moves to the initial position, it goes to the next step:
2.- Turn on the laser, for this, pin 5 (LD) of IC101 sends the turn-on signal to Q101, note that it is PNP, so in the base it must have 4.4V, this makes the laser turn on, it must so that you (with a small mirror) can see it clearly.
3.- Then the lens will go up and down two or three times looking to focus on the reflection of the laser beam, and when this occurs it will change the state of focus ok (pin28) and go to the next step:
4.- The rotation of the disk starts (spinle motor)
You must check if it has the 4.4V at the base of Q101, if the current is correct in R102, and if the signal is produced on focus ok (pin 28). If not, I would think about replacing the KSS-190A laser unit if the player deserves it.
The answer to the number at the laser pickup label is 560 which means 56 mA and I measured 55mA which should be fine.
Trident, I measured the bias voltage at the base of PNP transistor Q101 and it was at 3.6VDC instead of the specified 4.4VDC. In addition, the voltage at test point 10 measured 4.9 VDC instead of manufactured specified value of 10VDC. Obviously these voltage measurements are out of spec, please help with the next steps.
Trident, I measured the bias voltage at the base of PNP transistor Q101 and it was at 3.6VDC instead of the specified 4.4VDC. In addition, the voltage at test point 10 measured 4.9 VDC instead of manufactured specified value of 10VDC. Obviously these voltage measurements are out of spec, please help with the next steps.
Hi! TP+10 is connected to +5V. 4.9V is right.
The laser current raise with its use. It should be upper than 56ma. Another thing, I've seen that the laser power potentiometer, its value raise with age. This potentiometer is 2k2, I've seen it with 2.5K. This means this drift cause a descent in laser power.
I think the potentiometer must be adjuted again, try to upper a tiny the laser current.
If the cd starst tu play, test point TP RF should be adjusted at 1.2Vpp with a good disc in a oscilloscope.
If you don't have oscilloscope, try to upper laser current, don't surpass 70ma.
The laser current raise with its use. It should be upper than 56ma. Another thing, I've seen that the laser power potentiometer, its value raise with age. This potentiometer is 2k2, I've seen it with 2.5K. This means this drift cause a descent in laser power.
I think the potentiometer must be adjuted again, try to upper a tiny the laser current.
If the cd starst tu play, test point TP RF should be adjusted at 1.2Vpp with a good disc in a oscilloscope.
If you don't have oscilloscope, try to upper laser current, don't surpass 70ma.
I would add to the advice from ManoloMos that it's worth trying a few different discs as they vary somewhat in reflectivity. Also, you might find that increasing the focus gain a little can help get the player reading and playing, so that you can then make the correct adjustments to Focus bias and EF balance. Once these are optimised you can go back and adjust focus gain to the best adjustment.
Is the tiny brown potentiometer, below green capacitor. To increase power, CCW, to decrease CW.
Shared album - José Manuel Morales Hernández - Google Photos
Shared album - José Manuel Morales Hernández - Google Photos
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