In article ,
says...

Firstly just wanna say to the Google Groups Einstein that the 18 year
period doesn't matter as long as the problem was solved and the guy is
still around on this earth. The Commode/Amiga retro-scene is very much
alive.

Now I have posted lots of pics and info in this thread. I have already
recapped the monitor and done a lot of measurements.

https://www.edaboard.com/threads/com...or-with-faint-
vertical-lines.396322/

I thought I'd also ask here as Alex faced the exact same problem.

It's odd to see such an old thread get resurrected, but it is still a
relevant post even if the original participants are no longer reading,
so in this case I don't think it's anything to get worked up about.

I see from that edaboard thread that you've already tried the most
likely solutions :-(

The slowly drifting *horizontal* lines you mention sound like hum bars,
i.e. excessive voltage ripple from the power supply making its way onto
the display. If this is the case you'd see two bars on screen at once
(100Hz ripple from a full-wave rectifier, on a screen with 50Hz vertical
refresh) Again, by far the most common cause is a bad filter capacitor
in the low-voltage power supply, but there can be other components at
fault. See https://www.repairfaq.org/sam/monfaq.htm#monrwphb

If you have access to an oscilloscope, you might want to check the
outputs of the power supply for unusually high ripple. In particular,
the output of the 12V DC regulator (IC403) ought to look nice and
stable, as the regulator should smooth out whatever makes it past the
filter capacitor.

Obligatory safety note: be very careful and don't work alone, these
things have some nasty voltages inside them (including that 125V DC
power supply output). I highly recommend the safety guidelines at
https://www.repairfaq.org/sam/monfaq.htm#montrbs

Rayner

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