Lyra said:
It was mechanical. It's a few years ago now, but I think it was a bent-up metal tab which stopped the carriage at the inner end. It just needed a small tweak with the pliers to let the pickup carriage go a little further.
Colin
Have made some measurements and.....
The current drawn by the laser is within the specs (have the service-manual), and it reads allmost everything if it first manage to start......
The player have a +-10V supply feeding the (+ some other) opamp, and transistors driving the spindle-motor. This voltage is unregulated, and has a lot (0,5-1,5V) of ripple, and it is NOT +-10V!!!!!!
When measured with multimeter i got +15V -13V, and with my old oscilloscop I got allmot +17V, and - 15V.
One thing that is strange....when I feed the player a "difficult" CD it more often start playing it if I hold/ brake down the speed of the CD-spin a little. I can see the voltage to the motor increases when i touch the CD, and then it manage to start......
Don't know for sure, but it should be of no problem if I rebuild this supply to +-10V regulated (78xx) ???
The 78xx are not the best choice, but it is fast to implement......and compared to unregulated..........
Lyra
The current drawn by the laser is within the specs (have the service-manual), and it reads allmost everything if it first manage to start......
The player have a +-10V supply feeding the (+ some other) opamp, and transistors driving the spindle-motor. This voltage is unregulated, and has a lot (0,5-1,5V) of ripple, and it is NOT +-10V!!!!!!
When measured with multimeter i got +15V -13V, and with my old oscilloscop I got allmot +17V, and - 15V.
One thing that is strange....when I feed the player a "difficult" CD it more often start playing it if I hold/ brake down the speed of the CD-spin a little. I can see the voltage to the motor increases when i touch the CD, and then it manage to start......
Don't know for sure, but it should be of no problem if I rebuild this supply to +-10V regulated (78xx) ???
The 78xx are not the best choice, but it is fast to implement......and compared to unregulated..........
Lyra
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