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Vectrex Repair, help needed!

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Hey guys I'm going to try and make a long story short. back in Jaunary I got a broken Vectrex. I was told it had alignment issues. I trouble shooted and even replaced a few IC chips and got no results. Well today I repaired my Sega Mega Drive which got me motivated. So, here I am. The main problem is that the vectors displayed on my monitor don't connect and form what they should be. I shot a video to show exactly what I mean. Any help is appreciated.

 

https://www.youtube.com/watch?v=nQU7EVS3rho&list=UU3dpEsu_UykWMc9nPHdHwIg

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It is not the tube.

I repaired one with "sound ok, but just a white dot."

It was an IC with a heat sink attachment, on the power board under that giant heat sink, IC401 I think.

It is a chip that was used in Q*bert, but here is handling vectors, not sound.

It is good, except some vectors don't meet up, like yours but not that bad.

 

If you don't have an oscilloscope to adjust things like the repair manual shows, you need to find a low tech approach.

My thought was to measure resistance on a working Vectrex and match those values on the broken one and start from there.

You need to look close because there are 5 potentiometers, if I recall. The small one near the edge of the power board controls the high voltage.

There are 4 on the power board, and one on the CPU board.

This is the last repair step, adjustment with the test cart and an oscilloscope, following the service manual.

Test Cart is on the multicarts. Madtronix.com classic cart 1 Multicart has Test Cart 4.0.

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Yeah unfortunately i don't Havana oscilloscope. I spent about $50 on the vectrex so I'm not trying to spend more than its worth. I do remember once upon a time tweaking one of the knobs, it made the pictures move almost off screen and barley visible, and caused things to look a little different. That probably wasn't of much help but thought I'd include it anyway. Where do i go from here? I can shoot videos if you need one. Thanks for the reply.

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I would start by replacing caps. It's cheap and even it it doesn't solve your problem, it can do only good to your Vectrex.

And 50$ is dirt cheap for a Vectrex.

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I could give you resistance values for all the potentiometers in my working Vectrex.

That might be a good point to start.

Then you really need Test Cart and do all the adjustments you can follow (obviously not oscilloscope measurements).

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I can't display the video ("The video is not availabel"). Cencorship or error?

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Couldn't tell you what happened to the original video, but I have one that is doesn't something very similar to what was described originally. I have replaced the integrator capacitors but it didn't fix the issue on this one. I've been told I'm looking at ICs needing to be replaced, but since I have another fully working Vectrex, I've decided to keep this one around as a parts unit. Additionally the case on the one in this video is in bad shape with at least one broken screw post inside and lots of other cracks. Still here is the video of mine...

 

http://tinyurl.com/zxn4s66

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I can't display the video ("The video is not availabel"). Cencorship or error?

The reason is because it was from over a year ago.

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I can't display the video ("The video is not availabel"). Cencorship or error?

I actually deleted it, seeing a broken vectrex every time I checked my youtube channel depressed the hell out of me, not to mention it didn't get much attention.

 

Couldn't tell you what happened to the original video, but I have one that is doesn't something very similar to what was described originally. I have replaced the integrator capacitors but it didn't fix the issue on this one. I've been told I'm looking at ICs needing to be replaced, but since I have another fully working Vectrex, I've decided to keep this one around as a parts unit. Additionally the case on the one in this video is in bad shape with at least one broken screw post inside and lots of other cracks. Still here is the video of mine...

 

http://tinyurl.com/zxn4s66

It's very similar to you're issue, mine has the distorted, unconnected vectors but without the violent shaking yours has. I opened it up a year or so ago, bought the best quality capacitors I could find, but gave up half way thru it. Don't know why but evey time I attempt to work on it (which isn't often) I feel so overwhelmed by it and just put it back down.

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I was advised that the one I posted in the video needs IC chips replaced at this point as capacitors have been replaced without change. So..based on that and the fact that the case is pretty trashed, I just decided it would be best to leave for now and use it as a parts machine.

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I was advised that the one I posted in the video needs IC chips replaced at this point as capacitors have been replaced without change. So..based on that and the fact that the case is pretty trashed, I just decided it would be best to leave for now and use it as a parts machine.

What IC chips were you told to replace? I'm gonna mess around with my vectrex for a bit tomorrow

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Let me dig through my emails...hold.....hold.....

 

Here is quote from an email I received when I asked about my particular vectrex to an expert... Though keep in mind I haven't done any of this because again, I've decided it is best to keep it for parts to keep my other perfectly good vectrex running for the years to come.

 

"I'm not sure but it looks like a problem in the low voltage analog section on the logic board. Like IC303, IC304, IC305.

 

Your Z access is stable but something is making the X/Y voltages unpredictable. Have you tried reseating the above chips? Also you could try pushing on them while running or hitting them with freeze spray to see if things change.

 

Maybe, and I'm just not sure enough to know what the symptoms are, but if the ZERO line from the 6522A wasn't cleanly able to reset the integrators, that could be the problem? Not necessarily that the 6522 chip is bad, but ZERO passes through Q302. ZERO is used as a reference voltage and resets the beam position to center. If it was floating all around and not a clean 0 volts you might end up with these issues.

 

Skip to the integrator portion of this for an explanation of how the integrators are used to position the beam:

 

http://vectrexmuseum.com/share/coder/other/TEXT/VECTREX/INTERNAL.TXT

 

"

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Thanks for the fast reply, coincidently, as soon as I sat down to work on the vectrex I got the reply notification. I replaced a few caps and will continue more Friday, I tried removing the heat sync protected IC chip but that thing wouldn't budge.

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