Next N4000 Megapixel -- whats c57 and C201B?

From: Claude.W <claudew_at_videotron.ca>
Date: Fri Jul 27 13:07:54 2001

Hi

> > I have "restored" and tested the CRT on the N4000 (part no 135.00)
MegaPixel
> > monitor and seems to be ok on a Sencore CRT tester...dont think it would
> > last for years now but should be giving a picture....
> >
> > But I am still without a picture.
> >
> > When power is turned on, I can hear the HV "crackle" for a fraction of a
> > second but then no HV.
>
> Do you know just what is shutting down? For example, are the low voltage
> lines from the mains PSU (presumably switch-mode, but I'd not bet on it)
> present after shut-down?

B+ looks like about 90VDC kinda low....but that monitor quite different....

> > I dont know if someone played around in this monitor but on the
verticaly
> > mounted board ("analog board"?) C57 and C201B (top near flyback) are
>
> One thought. C201B sounds like it might be associated with C201A. It was
> quite common to have 2 positions in parallel for some capacitors in some
> machines so that it would be possible to make up the correct value (say
> to compensate for differences in the flyback or CRT). You could easily
> check if this is the case, and whether C201A is present or not.

Cant locate a C201A. The 2 mosFETS and their heatsink that serve as HOT
arent getting warm Id have to check if some kinda pulse is getting there but
was trying to see if someone had repaired a few of these and could tell me
common failures...

Claude
Received on Fri Jul 27 2001 - 13:07:54 BST