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yalokinh

bought a broken vectrex, hopeful in repairing it.

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Hello guys and gals,

 

I just bought a broken vectrex on ebay for cheap and the first thing I noticed when I turned it one was that the graphics are collapsed into a neat horizontal line. You can see the little lights move when the game starts up so it is reacting to the game, which I think is good. the controllers work and the sound is excellent.

I removed the back (carefully of course) and noticed that the 353ic gets really hot when the vectrex is on, could it be that the chip itself is fried? or is something happening elsewhere that is causing that chip to overheat?

 

I ordered that same chip on ebay because it is probably bad, but how should I check for problems elsewhere? I'll have an update video if the chip does in fact fix anything but until then here is a short one I just took.

 

any information is appreciated, let's get it fixed!

 

http://youtu.be/1hGm4IlEn8A

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Look this thread: http://atariage.com/forums/topic/219152-vectrex-screen-centering-help/ post n. 12

 

if I were you I'd try to operate anti-clockwise on the (circle yellow) resistor on the TOP of the second picture. It's the vertical strech resistor

 

PLEASE BE CAREFUL the CRT tube can electric shock you to death.

 

Use something plastic (I used a bic pen with a zip tie wrap taped on it, using the tip to turn the resistor).

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Thanks for the replies, I don't intend on dying and thats why I haven't messed around with it too much lately.

when I replace the ics, if it still is busted, I'll tinker some more around it.

Update video soon to come.

Thanks

-Yalo

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Discharging the CRT is super easy, I always do it before working on my Vectrex. People on the Internet make it sound like you will die if you even look at the CRT wrong, but it's a very simple procedure.

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https://www.youtube.com/watch?v=TUFFnwwpKzg&feature=youtube_gdata_player

 

 

Alright so i got the new ics. The little one is still gets way too hot, so its not the ic itself. It did change the screen though, now i get moving dots and lines, but still not playable. What should be my next step. Someone told me a cap kit is in order, but dont want to change them if that isnt he problem.

I will discharge the crt soon, have to buy some hings first.

thanks,

-yalo

Edited by yalokinh

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Cap kit is the first step when dealing with a collapsed monitor. Just be absolutely sure of what you are doing as a shock from a monitor is no joke. If you aren't 100% sure, have someone that is do the work.

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The buzzing is normal that hum is one of my favorite parts of the vectrex not sure why. It seems as though the vertical deflection of the beam toward the top of the vectrex is good but not the vertical deflection towards the bottom. Also the horizontal deflection to the right is good (that is right from the vectrex's point of view). Horizontal deflection to the left also seems to be an issue. Hopefully it is something that controls that magnetic coils and not the coils themselves. Thats all I can tell you I don't know too much about vectrex circuitry just a little bit about crt's.

Edited by Dripfree

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I discharge mine every time I work in the back.

I use a chisel that has a long shaft with a big plastic handle. Slide the flat part under the cup on the tube until you are touching one of the two wire spring clip things. Then take a long screwdriver, holding both by the plastic/rubber handles, and short the chisel to ground. I usually touch the screwdriver tip to the large ground strap around the tube.

 

If I have just unplugged it, there will be a small spark. Like a static spark, but much higher amperage.

If it has been off a few minutes, there is no spark. <<< This goes against everything I've read.

(Unless there is a discharging circuit) tubes and capacitors can hold there charge for years.

It seems that the Vectrex charge dissipates quite fast, but I wouldn't know how fast.

 

Be smart and use caution, but it is easy to do.

When it is on there is high voltage that could hurt/kill, but so can a toaster hurt or kill you.

One I have fixed was an IC on the other, power board. There is a post here about it.

Hard to get to under that long heat sink.

It is still not 100% because I think the wires between the CPU and the power board are bad.

That is a bad design to have the x y z signals go thru wires ending in connectors (my opinion), and for a lot of broken Vectrex it is this wire (loose or dirty connection) that causes failure.

I think if the computer board is working, (have sound), there is the best chance of a fix.

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Thanks for the replies!

I have to buy long metal rods with insulation in order to discharge it, I dont have anything at the moment so itll take me a while.

Ill go ahead and order a capacitor kit and replace them,. I notices some white residues under the volt regulators, is this normal? Metal is a bit discolored as well... besides that and the 30+ years of dust, everything looks ok.

 

Ive read that there is a common problem with the power, how do I check for this? Im not quite understanding some of the techjargon in some forum discussions (Im a dabbler, not at all well educated haha)

 

I loooove the vectrex buzz, i dont know why either, but my favorite game is berzerk so the buzz definitely adds atmosphere thats pretty bonechilling.

 

I really hope the cap kit does it, i dont think i could handle any of the more complex issues.

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I, personally, wouldn't do a cap next.

Having done one, the problems are that it is easy to lift traces, the large ones are glued down, the large ones take a lot of heat to melt the solder (which can lift the traces). And the fact that it didn't fix my Vectrex. (It was IC401, on the power board, not socketed, under the giant heat sink [because it gets hot] and it controls the beam). My problem was a white dot, not a line/lines.

 

The power lines are a three thick wires, yellow and orange, that go to the back center of the CPU board. It should measure 5V plus and minus if I remember correctly.

 

The x y z lines go from the two wheel pots on the CPU to the bottom center of the power board.

 

The black and white wire that goes between is sound.

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Good luck..

You really don't need long metal rods..

As IEPOSTA said, just use chisel or a screwdriver.

When I've discharged my monitors (not a Vec one yet), I use a screwdriver (good size with plastic handle) and a wire with 2 clips (1 on each end). One clip is on the screwdriver and the other goes to a ground.

I usually use an external ground, rather than the Vec chasis, but not sure why.. ;-)

 

I also have a pair of rubber gloves I got with a Rotisserie grill that helps me feel even more safe.. ;-)

 

But, as I usually wait a few days, I've never even had a big spark...

 

My vec takes a while to power up if I haven't used it for a bit, which I'm pretty sure is a CAP issue.

Tempted to do a cap kit, but I've seen "the experts" (which I define as random guys on the internet who a much better than I am) split over this.

Some say, once you have it open, replace them all.

Some say, just replace the ones that are actually bad..

 

I'm leaning towards the latter, but haven't got the nerve yet..

I also have to check my multimeter. I have one that will do CAPs, but I have to check the range of CAPs it will do..

 

desiv

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Thanks for the info. I'll break out the multimeter over the weekend and take a few readings.

what could be causing the 353ic(?) to overheat?

thanks,

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Thanks for the info. I'll break out the multimeter over the weekend and take a few readings.

what could be causing the 353ic(?) to overheat?

thanks,

Are you sure it's overheating? Have you measured the temperature? Unless you have compared it to an operating machine, you won't know what normal temp is in this application.

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Are you sure it's overheating? Have you measured the temperature? Unless you have compared it to an operating machine, you won't know what normal temp is in this application.

Its almost too hot to even touch when its on, I don't know if this would be normal but I suspect its getting fried by something.

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Its almost too hot to even touch when its on, I don't know if this would be normal but I suspect its getting fried by something.

It's an op amp, and could get too hot too touch and still be in normal operating temperature range, but I'm not sure they would let it get that hot without putting a heat sink on it. It's possible something down stream is drawing too much power. Are there any schematics floating around the web?

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Ok so I checked the voltages today on both the logic and power board, and everything checks out. I got 5V, -5V, -13V, seems normal.

 

I don't have any tools to discharge it so that's why it'll take a while, need to go down to the store and get some.

 

Every time I turn it on I get different results, its pretty weird. Usually I get the loud buzz with the dots and lines, then sometimes I get no buzz and only 2 dots with no lines.

Sometimes there is nothing on the screen, you can kind of tell there is something going on out of range.

What on earth is going on?

 

Edit: So I decided to change out the little chip twice just to make sure... and now I only get the two dots but consistently in the same place on the screen. Is the single dot problem similar to the two dots??

Edited by yalokinh

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It's an op amp, and could get too hot too touch and still be in normal operating temperature range, but I'm not sure they would let it get that hot without putting a heat sink on it. It's possible something down stream is drawing too much power. Are there any schematics floating around the web?

As far as I know, its not supposed to get that hot. I put in a brand new one in and it got instantly fried, took a thermal reading and I didn't dare go beyond 110*C!!!

Just to be safe I tried it again with another brand new chip and got the same result. definitely something there.

 

Edit: tried it again and it seems to be fixed, doesn't get hot at all, no Idea why it works now but not before.

Edited by yalokinh

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As far as I know, its not supposed to get that hot. I put in a brand new one in and it got instantly fried, took a thermal reading and I didn't dare go beyond 110*C!!!

Just to be safe I tried it again with another brand new chip and got the same result. definitely something there.

 

Edit: tried it again and it seems to be fixed, doesn't get hot at all, no Idea why it works now but not before.

110C is definately too hot. The spec limit is probably closer to 70C.

 

edit: found this link to the service manual.

 

http://www.playvectrex.com/shoptalk/vecman.pdf

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Here is a picture of discharging the Vectrex CRT (not mine):

post-29575-0-15919600-1393111593_thumb.jpg

 

I just use a 2nd screwdriver to "bridge" the 1st tool under the cup with the ground strap.

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It says on a sticker inside the back part of the case you should only discharge to the cage around the flyback (LOPT) - that's where the cable goes from the suction cup.

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