RE: Star Wars OVERVOLTAGE

I have never let it run for more than a couple seconds with the over
voltage off just to see what the meter is reading. So maybe it'll
only have hurt me by a month or so...

Remember my broken Wintron HVT that I sent back was putting out NO
high voltage, yet the red led was lit up. That's why I am
questioning whether or not I really am overvolting.

You are right, I did mean BU406D, and I have several of them. In
fact, I have 2 or 3 of just about every part on the entire board,
even the red mystery can.

If, in fact, it IS overvolting, what would cause that? The HVT
itself?

I guess I should buy the probe since apparently I'm going to need it
for working on this machine. So while I'm waiting, what else should
I be checking? (Other than what I've already done, of course).

Thanks!

On Thu, 25 Mar 2004 13:21:12 -0600, Joe wrote:
>
>
>Well, first off - NEVER NEVER disable the over voltage unless you
>REALLY know what you are doing and have the PROPER test equipment.
>Congrats, you probably are shortening your life span through X Ray
>radiation.
>
>If the over voltage protection is on, chances are there is a reason.
>You currently have no way of knowing if that HVT is putting out 19k
>or 29k. Checking the +180 may not be an accurate indication of what
>id going on. Especially when there is +180 produced by the
>deflection board.
>
>Now, what is a MPU401D??? Perhaps you mean a BU406D? That could be
>part of your problem.. If you dont have a BU, get one or more - they
>are very cheap on my site - www.joesarcade.com
>
>Next, get a HV prob from ebay or wherever. I tend to prefer the type
>that is self contained where you just shove the steel tip under the
>cup and ground an alligator clip. The choice is up to you. I picked
>mine up for about $25 shipped.
>
>Now, while that stuff is coming in you have plenty of time to test
>components......
>
>
>JB
>
>________________________________
>
>From: owner-vectorlist@vectorlist.org on behalf of Jonathan Stanley
>Sent: Thu 3/25/2004 12:33 PM
>To: vectorlist@vectorlist.org
>Subject: Re: VECTOR: Star Wars OVERVOLTAGE
>
>
>
>Let me add a couple things I've checked since my last post:
>
>The overvoltage LED stays on even when CR1 is pulled and the crt is
>working. (That's probably normal)
>
>My MPU401D did not fail when the Wintron did, but I did replace it
>with a new one anyway - no change.
>
>Since Q4 MCR100-3 seems to be an important part of the overvoltage
>section, I replaced it even though it tested ok. No change.
>
>To see if I really am getting overvoltage, I replaced R6 with a 2.2K
>resistor which should have knocked a good 5KV or more off the signal
>- overvoltage LED still on, so I put the 3.9K resistor back in.
>
>I checked Q4 from the focus block to the board, solid, ohms out.
>
>I checked the DAG ground wiring, solid, ohms out.
>
>I rechecked all the resistors in the overvoltage circuit - all
within
>spec.
>
>Remember, the game looks and plays perfectly when I have CR1 pulled,
>and plenty of range on my brightness control. It is probably at 45%
>so I have lots of range either direction. In fact, both R7 and R17
>are just about in their mid-points. (Oh, and I checked R7 and R17
>for proper resistance as well).
>
>Is it possible the LED could be "lying" and that I don't really have
>an overvoltage problem? What could cause that?
>
>Thanks!
>
>
>
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Received on Thu Mar 25 15:25:40 2004