I've had a harmon kardon DVD10 for quite a while now, it's been unused for about 1 year now due to it always having problems reading discs, if it does read them, after a min or two of playing (sometimes more) it will sit there scanning the disc like it can't read it and eventually says "disc error" i originally had this problem under warranty and they fixed it - aparantly adjusted the laser (i still don't think they did anything!)... Now i want to take a stab at fixing it, there doesn't appear to be any dry joints, etc the transport has "TVM502A" on the side as the part.. The laser seems to focus right (see point through disc, obviously not looking at it!) and it seems to read fine then after a while just decides it's had enough, some discs won't read at all even for 1 min!
Can anyone help me with any diagnosis/help fixing it?
Thanks
Aaron
Can anyone help me with any diagnosis/help fixing it?
Thanks
Aaron
Hi NUTTTR,
Service DID adjust the laser - the output of the laser diode.
This is what I posted before:
"Check your PCB and look for a test point labelled RF. Monitor the RF signal on oscilloscope and look for an eye-pattern. It should be 1.5(+ or - 0.3) Vp-p. If it is lower than 1.2V you'll have the problem where the pick-up reads some disks, and does not read ones with low reflectivity. You can increase the laser output by adjusting the little trim-pot located on the pickup itself. Do not go over 1.7 - 1.8 volts."
Nick
Service DID adjust the laser - the output of the laser diode.
This is what I posted before:
"Check your PCB and look for a test point labelled RF. Monitor the RF signal on oscilloscope and look for an eye-pattern. It should be 1.5(+ or - 0.3) Vp-p. If it is lower than 1.2V you'll have the problem where the pick-up reads some disks, and does not read ones with low reflectivity. You can increase the laser output by adjusting the little trim-pot located on the pickup itself. Do not go over 1.7 - 1.8 volts."
Nick
Hi Nick,
Thanks heaps for that!
I just measured it and it's more like 2.1 or 2.15 volts!! Nothing even close to 1.5! Will this mean shorter life for the laser? i have a funny feeling there's something else wrong and they adjusted it to cover up the problem?
Not sure, i will look into it more
Thanks
Aaron
Thanks heaps for that!
I just measured it and it's more like 2.1 or 2.15 volts!! Nothing even close to 1.5! Will this mean shorter life for the laser? i have a funny feeling there's something else wrong and they adjusted it to cover up the problem?
Not sure, i will look into it more
Thanks
Aaron
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