NMS8235 distorted image

By Igmar Palsenberg

Supporter (6)

Igmar Palsenberg's picture

07-04-2019, 17:11

Hi,

I just got my hands on an NMS8235, and hooked it up to a screen that still has a composite connection.
I do get image, but a few things stand out :

- The letters kinda flicker, it's like a screen was overlayed on top of it. Image also doesn't look very sharp
- The drive is toast : It makes all kinds of sound, and definitely not the right ones.
- Audio has a standard buzzing sound

Anyone has an idea where to start lookup ? I suspend the power supply, also due to the buzzing.

Pointers appreciated, before I hook up a scope.

Regards,

Igmar

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By Jipe

Paragon (1366)

Jipe's picture

07-04-2019, 18:15

it's the original disk drive or a 720k PC adapt ?
check the belt if original

By Igmar Palsenberg

Supporter (6)

Igmar Palsenberg's picture

07-04-2019, 18:44

The disk drive is an original. I'm planning to replace with a PC adapt, but first want to fix the other issue.

By Jipe

Paragon (1366)

Jipe's picture

07-04-2019, 20:20

first point : check the power supply +5v +12v with a multimeter

By Igmar Palsenberg

Supporter (6)

Igmar Palsenberg's picture

07-04-2019, 21:25

The voltages are there, and look OK. I have a hunch that it's not a clear voltage, but I need a scope to see
if I'm right. I was hoping someone already had this issue, and could give me some pointers :-)

By Alexey

Guardian (2458)

Alexey's picture

07-04-2019, 22:44

Recap

By Igmar Palsenberg

Supporter (6)

Igmar Palsenberg's picture

08-04-2019, 21:44

I'll start with that indeed.