Re: More Monitor Problems (V2000 contrast)

-----Original Message-----
From: James G Watt <kinetic-arts@ntlworld.com>
To: vectorlist@synthcom.com
Date: Fri, 23 Aug 2002 01:26:17 +0100
Subject: VECTOR: More Monitor Problems (V2000 contrast)

>
> Having given up on fixing the spot killer on my v2000 for the moment I
> thought I'd concentrate on a more serious problem.
>
> (thanks paul for the help up till now btw)
>
> The contrast on this monitor appears to have gone - or at least only
> work over a very narrow range. I can only adjust the monitor so the
> vector construction lines are invisible by turning the contrast right up
> and adjusting the brightness right down. When I do this you can hardly
> see normal details like asteroids though.
>
> I've changed out the game PCB to eliminate that as the cause of the
> fault.
>
> I've had all the transistors in the Z section of the circuit out and
> they appear to test OK.
>
> I've replaced all the electrolytic caps in the monitor.
>
> I then tested the voltages being supplied to the vector section. This is
> what I found:
>
> Voltages on p500
>
> pin manual actual
> 1 95 103
> 2 30 17
> 3 94.5 71
>
> 5 98 71- is this off enough to be causing the problem?
> 6 38 36
>
>
> Anyone got any ideas on what the next step should be?
> ---
>
I have seen this in televisions before,
check the value of any resistors between the tube-neck and the HV circuits, one
may have changed value.

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Received on Thu Aug 22 23:48:13 2002