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Discman D-50 MK2 not booting error

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Post time 2021-02-09 02:48:18 | Show all posts |Read mode
I own a D-50 MK2 discman that is doing fine. Recently, out of curiosity I have replaced 2 opamp 4560 with op275 (ic102, ic202).
When I start it up, a sound comes out at the output, but wrong for a few seconds, the engine stops working.
When I try to start the motor spins for a few seconds, the LCD lights up, but turns off after a few seconds. Repeatedly pressing "PLAY", the engine does not respond!
Leave it on for a few minutes, if you press "PLAY", the same situation will be repeated as above ???
I replaced back ic102,202 with NJM4560 as original but it still does not improve anything!
I check CPU (ic801) Vcc pin, RST is normal, only pin 30 (P-CON) only first time is from H - >> L (5v -> 0v), all the times after is from 5v-> 5.8v ??? Makes it bootable! When khi "PLAY" , 9v, 5v, -5v is good.
I think ic801 is faulty, so I have replaced it with another one which is working fine. But the situation is still not improving! Still have the same situation as before.
Please help me locate the error and localize the damage! thank you very much Mrs Gu! Sorry for my bad English!


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Post time 2021-02-09 19:17:02 | Show all posts
The OP275 can directly replace the NJM4560. The power range of the OP275 is from +-5 to +-25. The power supply of NJM4560 is +-5.2 which is suitable to power OP275. What my guess is the leaking static electricity from your soldering iron damaged something like your laser diode? Pls double check whether your laser is still working with red beam emitting. If LCD has display, the CPU should be fine.
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 Author| Post time 2021-02-10 20:41:04 | Show all posts
I thank your comments for the breakdown of the D-5 MK2. But I wonder why, for a while, when the motor is turned on, the spin and sled motor is spinning and moving and only once? (check the battery 30 from 5v-> 0v), the next time only LCD open 0:00 (battery 30 from 5v increased to 5.8v ~ 6v), so can not make the DC-DC converter work? I have a real headache because of this incident, if it dies it would probably be easier to fix than something like this
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Post time 2022-03-02 10:43:02 | Show all posts
You'll check the DC_DC box of the output +5.2V and -5.2V. It seems you have issue with it.
DIsassembling the DC-DC box, apply 9V to VCC_In, connect a 10K resistor between VCC_IN and ON/OFF pin, you can measure +5.2V and -5.2V on corresponding pins.
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