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Panasonic NP1

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Post time 2022-10-22 04:42:13 | Show all posts |Read mode
Just purchased a Panasonic SL-NP1 as not working for about USD 15.
I found this player very interesting because it seems to be the exact same as Technics XP1, but there is very little info on this Panasonic version.
As for the repair, it was very interesting as well. I noticed two missing screws so I knew it had been opened before.  Everything inside seemed fine, no corrosion, but quite some dust. I took out the mechanism to clean and check the spindle. The disc table had dropped, but after readjusting, the spindle motor was unstuck. After this the player powered up fine. (Seller said it didn't stay powered on)

On power up I saw the LCD turn on, the laser lighting up and the focus moving, so I knew most of it was alive. But I was afraid to notice that all the potentiometers seemed to be in the middle... like if someone that didn't know just moved them around (remember the missing screws?). I feared having to realign everyting.

I decided to just put a disc in and test. To my surprise it played perfectly! Tried with some problematic discs and even CD-Rs, and all read without problem.

Later I realized that on the top layer there are printed resistors, laser-trimmed to value. So I guess the resulting tolerance is good enough that the servo potentiometers don't need to be adjusted too much at the factory. And they're not exactly centered, they are between 3 and 5 degrees rotated ;)
Very interesting PCB construction, the traces on the same top layer appear to be conductive ink. And apparently very reliable, dating from 1990.


So in the end, nothing major needed repair, I just gave the plastics a good wash. Trying to polish the acrylic windows. And waiting for good light tomorrow for pictures

Any more info on this player?


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Post time 2022-10-22 20:28:16 | Show all posts
Glad to hear your good news, we are waiting to see your wonderful pics, including both internal and external. Thanks!
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 Author| Post time 2022-10-25 04:32:42 | Show all posts
Internal
Top side

Here the printed resistors are visible

Bottom side


ICs are:
NJM3415 - Headphone amp
AN8083 - DC-DC controller
AN8387 (x2) - Motor and coil drivers
MN15845 - Microcontroller, LCD driver; 4-bit
LC3517 - 2 Kbit SRAM
MN6625 - DSP
SM5807 - digital filter (4x oversampling)
AN8373, AN8374 - not sure which is servo and which is servo processor (ASP)
The IC302 is very hard to read, I believe it's a NEC and by elimination has got to be the DAC.

With laser


Detail of top of PCB

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Post time 2022-10-25 11:26:48 | Show all posts
Yep, very nice! The film resistors can not be replaced once damaged. It's a cost-saving solution but not good for maintenance.
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