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Vectrex Display Problems PICS


pmpddytim

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I'm having some problems with my Vectrex.

 

It turns on, the sound works, I can even see the graphics. However all of the graphics are connected to a dot in the center of the screen with extra lines. Also the text is unreadable. Everything still moves on screen as it should its just those extra lines that all go to the center of the screen.

 

Any ideas?

 

Man, its hard to take pics of that thing!

 

-Tim

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Edited by pmpddytim
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Did you turn down the brightness? There's a knob on the back. I had one that looked just like that.

 

 

y-bot

 

Yeah, if you adjust it where you can't see the lines anymore, you can barley see the graphics your supposed to see. Plus the text is still just a series of lines. not actual characters.

 

-Tim

Edited by pmpddytim
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First, let me say I know almost zilch about the guts of a Vectrex, but I do know how CRT displays work. It seems to me that there's something wrong with the blanking circuit, which should turn off the beam during the time that you see those extra radial lines. It could be a bad transistor or a chip, but you should probably get someone experienced in Vectrex repair to diagnose and fix it. Regarding the text problem, it may be related to the blanking problem, or it may be a completely separate issue.

Edited by A.J. Franzman
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I think that Sunmark used to fix these. I don't know if he does repairs anymore or not. You could try to contact him. I have sold a couple of broken Vectrex systems on eBay as well. If you don't feel like having it repaired you could sell the controller separate (probably would get about $30-$40 for it) and also sell the broken Vectrex separate (might get $10-$25 for it).

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Did you adjust it down till you see a very faint white dot/no dot in the center? Did you turn the knob back and forth several times to clean the oxidation from the "pot"? You need to do this the full range of them every so often on the volume and the brightness knobs while the unit is off.Has it been awhile since your last use? Let it warm up.Is it in a cold room?Let it stay on a bit.Is it by your fridge,pc,microwave or tv? On the same outlet/breaker as these?Are you giving it rf interference like this?

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My one and only Vectrex (purchased for $20 a few years back) has the same problem as the one you're describing. I am a bit ashamed to admit it, but if I slap the back part of the top of the case with a bit of force, the problem corrects itself. I haven't bought a replacement Vectrex system because, well, this oldie but goody is still working, albeit only after receiving a "love tap". :ponder:

Edited by Clean Larry
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My one and only Vectrex (purchased for $20 a few years back) has the same problem as the one you're describing. I am a bit ashamed to admit it, but if I slap the back part of the top of the case with a bit of force, the problem corrects itself. I haven't bought a replacement Vectrex system because, well, this oldie but goody is still working, albeit only after receiving a "love tap". :ponder:

If giving it a whack "fixes" the problem temporarily, it's most likely either a dirty/bad pot, or a cracked solder joint or circuit track.

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The last Vectrex that I saw do this needed the X/Y/Z signal cable reseated. The Z part, specifically.

I'll buy that. A poor cable connector contact can act much the same as the other problems I mentioned. If you're adept enough to safely open your Vectrex, unplugging and replugging any cables you can (except the fat one that goes to the suction-cup like thing on the side of the picture tube -- that one is where the high voltage lives; very dangerous, leave it alone!) might clear up the problem. If you happen to notice while doing this that any particular connector seems especially loose, you might even be able to tweak the contacts a bit to increase their pressure. I'm sure FABombjoy or someone can describe exactly which cable he referred to, to speed things up if the Vectrex has a bunch of cables in it.

Edited by A.J. Franzman
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My one and only Vectrex (purchased for $20 a few years back) has the same problem as the one you're describing. I am a bit ashamed to admit it, but if I slap the back part of the top of the case with a bit of force, the problem corrects itself. I haven't bought a replacement Vectrex system because, well, this oldie but goody is still working, albeit only after receiving a "love tap". :ponder:

It could also be the solder joint of a cable connector. I had an old 128K Mac (which had been upgraded to 2M of RAM) and after a couple of years the video would just flip off. Whacking it caused it to work again. I eventually found the cause was that the video pin of the analog board connector on the motherboard had a ring crack in the solder joint. It just needed to be reheated.

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You should be able to reseat that cable without getting too close to the HV section.

 

The boards in a Vec are in 2 parts: the logic board, which is at the bottom of the unit, and the HV / power suppy board, which is mounted vertically & larger. The cable you want has a 4-pin connector on the logic board (but with only 3 wires). This connects to the HV board, and it splits into 2 seperate connectors: another 4-pin connector, and a 2-pin connector. The "Z" wire is the one that splits off into the 2-pin connector. It's worth reseating this wire before you get into testing failed components. I got my current Vec for super cheap because of this exact same problem.

 

There aren't very many wires that connect the logic & HV board, so it should be hard to miss.

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You should be able to reseat that cable without getting too close to the HV section.

 

The boards in a Vec are in 2 parts: the logic board, which is at the bottom of the unit, and the HV / power suppy board, which is mounted vertically & larger. The cable you want has a 4-pin connector on the logic board (but with only 3 wires). This connects to the HV board, and it splits into 2 seperate connectors: another 4-pin connector, and a 2-pin connector. The "Z" wire is the one that splits off into the 2-pin connector. It's worth reseating this wire before you get into testing failed components. I got my current Vec for super cheap because of this exact same problem.

 

There aren't very many wires that connect the logic & HV board, so it should be hard to miss.

 

I reseated all of the cables and nothing changed.

 

I took it apart the other day to see if I could see anything obvious and now it seems to work perfectly about 1 out of 25 or 30 times for one power cycle only. If you turn it off and on again its back to its old tricks.

 

Any other ideas? I have worked on an arcade monitor before so I'm aware of the danger, but I do thank everyone for warning me!

 

-Tim

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Man, its hard to take pics of that thing!

 

Do you have a digital camera that takes movies? Because you can take several seconds of footage, then export a frame as a photo, that's what I always do.

 

If you're adept enough to safely open your Vectrex, unplugging and replugging any cables you can (except the fat one that goes to the suction-cup like thing on the side of the picture tube -- that one is where the high voltage lives; very dangerous, leave it alone!)

 

Although Tim probably already knows about this, you can just leave the Vectrex off/unplugged for two days and it'll discharge itself, plus there's ways to manually do that if you do Vectrex searches around the internet (I'm not technically adept with the 'trex myself or else I would explain it ;) ).

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If you're adept enough to safely open your Vectrex, unplugging and replugging any cables you can (except the fat one that goes to the suction-cup like thing on the side of the picture tube -- that one is where the high voltage lives; very dangerous, leave it alone!)
Although Tim probably already knows about this, you can just leave the Vectrex off/unplugged for two days and it'll discharge itself, plus there's ways to manually do that if you do Vectrex searches around the internet (I'm not technically adept with the 'trex myself or else I would explain it ;) ).

Self-discharging (whether by design through a bleeder resistor, or naturally through leakage) is something I would never take for granted. Very few CRT TVs and monitors have any designed-in bleeder, and even if I knew any particular one did, I wouldn't assume that it's in working condition. Large CRTs can store enough charge to pack a nasty wallop for months without power. Though I wouldn't call the Vectrex CRT "large" by any means, I certainly don't want myself or anyone else to get zapped by one.

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Hey guys,

 

I'm having problems with a Vectrex too..

 

Can anyone tell me is the European MB Games Vectrex any different internally to the American GCE Vectrex?

 

I turn it on and get a white dot which moves very very slowly left for about 3 centimetres then stops.. I've tried checking the common fix for it but its not a bad solder joint there.

 

I don't get any sound at all that I'm aware of.. all I get is some crackling if I move the volume up and down..

 

Any ideas what to check? Could it be a 6522 VIA IC that I've read about elsewhere?

 

Cheers, don't mean to hijack thread but didn't think it was worth making a seperate thread.

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  • 7 years later...

Yeah as I mentioned in my PM, had the caps replaced by a local repair shop but it's not solved the problem. I opened the back up tonight and I can see that the pins on some of the ic's look a bit dodgy so I want to resit them but I'm worried about getting a bad shock. Never discharged a CRT before.

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IC doesn't work under heavy loads so go for it.

 

The only parts in a CRT that are heavily loaded are the flyback transformer and the screen itself; those parts :

flyback1.jpg

And the power boards. Mostly, avoid getting close to the larger capacitors.

 

 

 

High voltage doesn't kill. High current does.

A 1,5V battery able to deliver more than 50mA (or 0.05A) can kill you... if that current can flows through you (to the ground, or applied under your skin; actually, to overcome your skin resistance, the minimal voltage is around 50Vac/120Vcc on dry areas, 25Vac/50Vcc on moist areas). On the other hand, static electricity that make sparks when you get your hand near a metallic surface, those can build up high voltages.

The air resistance to voltage is approx 30kV/cm (can vary with humidity of course) which mean when you get an electric spark when your hand is at one mm (0.04 inches) of a metallic surface, you get a 3000V shock.

 

The large sparks you see in many shows and at the Palais de la Découverte (Museum of Discoveries, an intearctive museum/showroom of sciences in Paris) are even more powerful :

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This girl receive a spark that is carrying around 350 000V. And it happen every day at the Palais, and no one was ever killed by it.

 

I might have go overboard, but electricity is all around us, even part of us, so even if it can kill, you gotta know the dangers of it.

 

In a television, the 25V capacitors in the power supply are probably more dangerous than the 1000/5000V CRT itself... especially since most people won't look at them so carefully ;)

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Well somehow I've managed to make it worse.

 

I removed & replaced these chips (I didn't touch the sound chip as I replaced that a couple of years back) and now I'm not getting any vectors on screen... Not even a white dot.

 

30A5027B-B306-47C5-8A4F-0DE5FEDBEEF5_zps

 

The screen is still coming on and the sound is still working. The only time I see the dot is when I switch the Vectrex off. The white dot appears in the bottom left corner and moves very quickly to the centre before disappearing.

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