Re: VECTOR: G05_802 Glowing Blob in middle of screen ?

It might not be the same problem exactly, but if you have the older G05-801
Vector monitor, you might have bad pot's on the HV supply.
I had to replace both the contrast and brightness pots to get the monitor to
work really good.

Mendel

----- Original Message ----- 
From: "Colin Davies" <[email protected]>
To: <[email protected]>
Sent: Saturday, September 04, 2004 1:02 AM
Subject: VECTOR: G05_802 Glowing Blob in middle of screen ?


> Hi Guys... Just joined this list because I've aquired an Asteroids Cab...
>
> I'm Based in the UK near Liverpool and have a reasonable bit of
electronics
> / tech background.
>
>  To start the ball rolling, I'm currently having a problem with the
monitor
> and hoping someone can help me please.
>
>  I'm getting a glowing blob in the middle of the screen with the controls
> set up to give a fairly nice picture.
>
>  I've done a 'mock up' picture of what I'm seeing here...
>  http://uk.geocities.com/[email protected]/Astyblob.jpg
>
>  I've just set up the HV to about 11.5 Kv ( it was 12.7), I need to
>  measure/check other voltages yet (its a bit hard to work on at the
moment).
>
>  With the game board powered down.. I still get this 'blob' , and the spot
>  killer is illuminated. I've also tried another deflection board, and have
>  the same problem. I have tried adjusting the brightness and contrast...
> with
>  the brightness right down, the blob is still faintly visable but
obviously
> I
>  would have to play the game blind, If I turn the brightness  past normal
>  levels, the blob becomes a sharp dot / spot like the your ships bullet.
>
>  When I play the game, the blob is always in the middle, BUT when I go to
>  high score name entry.. the blob dissapears like magic and then reapears
on
>  the next 'game screen'....
>
>  I'm puzzled about this as this is the first Vector I've worked on.. Its
> been
>  suggested that the tube may need rejuvenating, but I can get a nice
bright
>  picture, whats the syptoms of a bad tube ?  I've not got another monitor
or
>  tube to try and do a swap test.
>
>  There is a dot of screen burn in the middle, but its been suggested that
> this is a symptom of my problem (when its been turned up) and not the
cause.
>
> If any one can shed any light on this please, I would be very grateful.
>
>  Thanks for reading,
> Regards, Colin
>
>
> --------------------------------------------------------------------------
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