RE: Major Havoc Screen problems

At 09:23 PM 9/6/2000 -0400, you wrote:

> Hi Jon,
>
> It does not appear to be the HV unit. I took that over to my friend's house and plopped it right into his and presto no problem. Also, my MH was not exhibiting blooming as I understand it. I didn't *really* see any magnifying glass look, rather it had looked like I took my x and Y size pots and adjusted them such that my game now displayed information well off the screen. There was no distortion in the images. Rather it was just like someone had scaled my picture up in size and I was only seeing some of the game on the screen. No mater how much I tried to reduce the screen size, there was a limit and text, scores etc were off the screen.
>
> Any ideas as to what is wrong with my MH board? Could this be caused by the deflection board? I am gonna try to replace this one as well to see if I get the same symptoms, but I don't know that my monitor would display these types of symptoms if it was a monitor problem.
>
> Anyhow, if anyone has any information that might help me, I would appreciate it.

The deflection board could be the cause of it, but I doubt it. Your best bet would be to test your pcb in you friends cab :) If the problem is in the pcb, I would make sure the pots are good and maybe rebuild the vector output section (TL082's & MC1495's).

Do the symptoms appear on both the X axis and the Y axis? If so, it could be a problem with the mathbox scaling - it seems odd that the same parts would go bad in both axis/axes (damn.. how the hell do you spell the plural form?) Anyway, this is something that is not fun to track down (well, I think its fun, but its certainly not easy).

> Since I am on the subject of Major Havoc, I have another boardset that is giving me different problems. This one seems to have stopped working on me... sort of. It was working fine and then it stopped working, or rather started working interemittedly. At first I thought it may be a connector problem or a trace problem, but the connector worked fine for my other MH boardset no matter how many times I connected or disconnected it. THis *bad* boardset would sometimes not work and I would disconnect, re-connect the connector many times plug it in, unplug, move the board around... sometimes this worked other times no go. There really didn't seem to be any correlation between me connecting/moving the board to when it would work vs not work. I cannot figure it out. Could it be a questionable capacitor somewhere or transistor? Also, while this board was actually working, I would jiggle the connector or press the board in various places (with a piece of wood) and it did no!
t cause the game to stop, reset or do anything funny. It was on for the long haul which makes me also believe that it was not a connector or bad trace issue.

Sounds like you need to attack that board with an eraser. What does it do when it doesn't work? Anything? Are the voltages ok on the board?

Jon

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Received on Thu Sep 7 08:14:54 2000