Re: Problem with Electrohome G07- only half picture

I'm beginning to think now that I might have a flakey V. Lin pot or
something in that circuit is flakey.. Everything was fine until I started
adjusting the linearity - then the left half of the screen slowly started
closing in. I'm sort of glad though - because typically games don't just
fix themselves permantly. Plus - I'm not quite so confused now about the
screen cut evenly in half. It could have been 3 quarters out or any ratio
for that matter.

Matt

----- Original Message -----
From: "John Robertson" <jrr@flippers.com>
To: <rasterlist@vectorlist.org>; <rasterlist@vectorlist.org>
Sent: Wednesday, July 30, 2003 11:08 AM
Subject: Re: RASTER: Problem with Electrohome G07- only half picture

> Hi Matt,
>
> I would suggest that you recheck the capacitor job you did...I instruct my
> staff to make sure the capacitors (particularly the larger ones) are flush
> to the board to reduce the risk of breaking traces if the capacitor is
> jiggled in normal use/re-installation of board).
>
> I suspect the large cap on the vertical deflection circuit has a cracked
> trace or possibly a cold solder joint. I see this every now and then on
> boards that had someone elses' work on the capacitors...
>
> John :-#)#
>
> At 10:19 AM 30/07/2003 -0700, Matt Rossiter wrote:
>
> >This morning I took another stab at trying to fix this problem with my
> >centipede monitor. This time I decided to unplug the yoke and start
tracing
> >signals from the yoke connector pins. I still had a hard time finding
any
> >thing unusual. After about 20 minutes I re-connected the yoke - and
> >badda-bing! Out of nowhere I finally got a full picture on my centipede.
I
> >honestly don't know what fixed the problem. I did take some readings
from
> >the wires on top of the yoke - so I figure maybe there was a loose
> >connection somewhere - but that doesn't seem to make sense why I'd get
just
> >half a picture. I'm stumped - but at least my Centipede works! (knock on
> >wood).
> >
> >
> >Matt
> >
> >
> >
> >----- Original Message -----
> >From: "Sean McLachlan" <sean@lithoflexo.com>
> >To: <rasterlist@vectorlist.org>
> >Sent: Monday, July 28, 2003 7:54 AM
> >Subject: RE: RASTER: Problem with Electrohome G07- only half picture
> >
> >
> > > You do if the monitor is mounted vertically. ;)
> > > I had a G07 that was doing the same thing, and one of the 400 series
> > > resistors was burnt open. I don't remember which one, it was so
obviously
> > > fried I replaced it without much thought. Rogers R420 suggestion
rings a
> > > bell, though.
> > >
> > > Sean McLachlan
> > > MIS Manager
> > > LithoFlexo grafics inc.
> > > 801.484.8503
> > >
> > > -----Original Message-----
> > > From: owner-rasterlist@vectorlist.org
> > > [mailto:owner-rasterlist@vectorlist.org]On Behalf Of SteveT
> > > Sent: Monday, July 28, 2003 8:58 AM
> > > To: rasterlist@vectorlist.org
> > > Subject: Re: RASTER: Problem with Electrohome G07- only half picture
> > >
> > >
> > > Matt
> > > If it displays the right half of the picture top to bottom -you do not
> >have
> > > a
> > > vertical problem.
> > >
> > > Matt Rossiter wrote:
> > >
> > > > Hey all,
> > > >
> > > > I brought home a Centipede that had a dead monitor. I replaced the
caps
> > > and
> > > > installed a new HV unit. It now powers up, but only displays the
right
> > > half
> > > > of the picture with a line running down the middle -looks like a
typical
> > > xy
> > > > failure but on a raster game. So, basically I have a vertical
> >deflection
> > > > problem.
> > > >
> > > > Here's what I've done so far...
> > > >
> > > > 1) Tested the transistors in the vertical output circuit - X401 and
> >X402 -
> > > > they test fine out of circuit. I believe the signals are good too
when
> > > > testing in circuit.
> > > > 2) FR401 (the fusible resistor) is fine.
> > > > 3) Checked the signals on IC 501 and they look good. Swapped in a
new
> >IC
> > > > just to be sure.
> > > > 4) Checked other resistors and capacitors within the vertical output
> > > > circuit.
> > > >
> > > > I just can't seem to trace down the problem, but it could be
something
> > > > simple I'm missing. Has anyone else run into a similar problem?
> > > >
> > > > Matt
> > > >
> > >
> >
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> > >
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Received on Wed Jul 30 17:18:54 2003