Very old monitor repair

[CIP]

Hi everybody,

I got an very old monochrome monitor that is dead.

It's an NEC BU-1201M(E)-1 from about 1985

It had an burnout fuse on the main board, replaced it but the screen remains
black. Audio works. When I switch it on the first second the end of the CTR
lights up but then it gets very dim or even no light at all. I can hear the
HV make a little hunnimg noise.

It's a monitor from a computer that controls a factory. The monitor was
turned on in 1985 and never turned off, but when not in use the screen was
cleared. The video input is NTSC

Checked the power transistors (h/v) and they are ok. Transformer is ok.

Anybody any tips?

 

[Aidan Grey]

Hi everybody,

I got an very old monochrome monitor that is dead.

It's an NEC BU-1201M(E)-1 from about 1985

It had an burnout fuse on the main board, replaced it but the screen remains
black. Audio works. When I switch it on the first second the end of the CTR
lights up but then it gets very dim or even no light at all. I can hear the
HV make a little hunnimg noise.

It's a monitor from a computer that controls a factory. The monitor was
turned on in 1985 and never turned off, but when not in use the screen was
cleared. The video input is NTSC

Checked the power transistors (h/v) and they are ok. Transformer is ok.

Anybody any tips?

NTSC is standard North American TV video. What you have essentially is a
monochrome
TV being used as a monitor.

You should be able to be able to cheaply buy a replacement TV type monitor.
One
place to check is video security monitors. A security camera being recorded
on a
VCR is using an NTSC signal. The video monitor for such a task would
probably be
a drop in replacement for your defective monitor.

Note that even if you could repair this monitor, it will not be reliable at
its age. A brand
new monitor will give you the reliability needed for a factory environment.


Aidan Grey

 

[Clint Sharp]

Hi everybody,

I got an very old monochrome monitor that is dead.

It's an NEC BU-1201M(E)-1 from about 1985

It had an burnout fuse on the main board, replaced it but the screen remains
black. Audio works. When I switch it on the first second the end of the CTR
lights up but then it gets very dim or even no light at all. I can hear the
HV make a little hunnimg noise.

The HV shouldn't hum, it should whistle, you can check for operation of
the flyback transformer by holding a neon screwdriver close to the
transformer, it should glow on a monochrome unit if it's running.

It's a monitor from a computer that controls a factory. The monitor was
turned on in 1985 and never turned off, but when not in use the screen was
cleared. The video input is NTSC

Checked the power transistors (h/v) and they are ok. Transformer is ok.

Anybody any tips?

Replace it, if it's in a factory it's needed! You could probably replace
it with a 12" PAL Unit and get away with it with a couple of minor
tweaks to the frame rate and line sync. http://rswww.com supply chassis
monitors as do many other 'industrial' electronics component suppliers.

 

[James Sweet]

NTSC is standard North American TV video. What you have essentially is a
monochrome
TV being used as a monitor.

You should be able to be able to cheaply buy a replacement TV type monitor.
One
place to check is video security monitors. A security camera being recorded
on a
VCR is using an NTSC signal. The video monitor for such a task would
probably be
a drop in replacement for your defective monitor.

Note that even if you could repair this monitor, it will not be reliable at
its age. A brand
new monitor will give you the reliability needed for a factory environment.


Aidan Grey

Don't forget that there might be special mounting considerations.

Also I would not nessesarily expect a modern TV to last anywhere near as
long as that monitor did, if the image was still reasonably good I'd repair
it personally.