Re: Problem with Electrohome G07- only half picture

Good point, I had not read deeply enough into your original post, I would
agree that a bad linearity pot could cause 1/2 screens...my suggestions
were for NO vertical deflection. Sorry!

John :-#)#

At 02:17 PM 30/07/2003 -0700, Matt Rossiter wrote:

>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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Received on Wed Jul 30 18:02:02 2003