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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 11th May 2016, 3:59 pm   #1
electronicskip
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Default Vectrex

Not quite sure if this is the right heading for a games machine but i was wondering if anyone else dabbled with the Vectrex vector based games machine?

Ive got a couple of these beauties which a tinker with and a good collection of the rom carts and overlays to go with it.
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Old 11th May 2016, 4:15 pm   #2
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Default Re: Vectrex

Yes, I know it well... I like vector machines in general, having also got a DEC GT40 terminal and an HP1350 'graphics translator' (vector display unit). I can start other threads for those if anyone is interested.

The Vectrex is based on a 68A09 processor with ROM (internal and the cartridge), a little RAM, and I/O. There is an AY-3-8910 sound chip. There is also one DAC which is used (along with sample and hold circuits) for the 2 deflection signals, intensity, another sound channel and digitising the joystick positions.

The video board drives a magnetically deflected (TV-type) CRT. There is a free-running EHT generator using what was probably a standard line output transfomer. You must set this up as in the service manual or the output transistor fails (don't ask...). The deflection uses an LM379 dual audio amplifier IC with sense resistors in the return leads from the yoke so as to provide a constant current drive. That IC is almost unobtainable now, it is by far the hardest component in the machine to find.

Games cartridges are just ROMs/EPROMs

There was also a light pen (quite conventional) and a 3D image (which was anything but). The latter consisted of a spectacle frame with a little DC motor on it spinning a disk in front of your eyes. Said disk had colour filter and black regions so, as it was synchronised to the vector generation, provided a colour and 3D display. The 3D mager is very hard to find (I don't have one and haven't tried to make one yet).

One good thing is that the manufacurers officially allowed everything associated with the system to be copied (possibly only for non-commercial use) when it went out of production. So you can download the service manual and images of the game ROMs if you want them.
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Old 11th May 2016, 5:59 pm   #3
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Default Re: Vectrex

I do have the lightpen but the 3D Glasses have eluded me mainly because of the stratospheric prices being asked for them.
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Old 11th May 2016, 9:31 pm   #4
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Default Re: Vectrex

There was a hack somewhere on the internet which involved gutting a personal CD player/discman and making a coloured wheel and then strapping the contraption to your head to play the 3D games! Not sure of the author if it it still can be found though. A great system, I have one in my collection which wasn't cheap but I had to have some sort of vector based system after selling my Star Wars arcade machine (another story... )

I do recall many years ago Woolworths in Liverpool selling off surplus Vectrex systems for £19.99 and the games fir £4.99, at the time I had a Sinclair Spectrum and thought "Looks poor and the games are black and white." If only i'd known...

Kev
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Old 12th May 2016, 12:04 pm   #5
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Default Re: Vectrex

Ah yes! that word "if only" hahaa
I do have most of the rom carts for the system as ive been collecting a long time ,but i also have a multi cart which incorporates a lot of the homebrew games which are available and one or two unfinished games.
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Old 12th May 2016, 3:09 pm   #6
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Default Re: Vectrex

Quote:
Originally Posted by Outrun_uk View Post
There was a hack somewhere on the internet which involved gutting a personal CD player/discman and making a coloured wheel and then strapping the contraption to your head to play the 3D games! Not sure of the author if it it still can be found though.
The author of his project can still be found. Just contact John on madtronix.com. Here is the contact form.
(http://www.madtronix.com/en/contact.html
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Old 12th May 2016, 10:54 pm   #7
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Default Re: Vectrex

I have two Vectrex machines. The first one I bought in 1984 from Dingle's department store in Bristol, when it was discontinued and reduced in price to £39.99 (they were originally £150 - £200 new, which was a lot of money back then, for what was essentially an electronic game.)

A few months after buying it, Woolworths in Broadmead, Bristol (may have been called 21st Century Shopping back then) cleared out their remaining stock of Vectrex game cartridges for £2.99 or less - some were only 99p! I bought all the different ones I could find, but couldn't get all the titles.

Then in 1995 I got on the Internet and discovered there was a thriving community of Vectrex enthusiasts in the USA. The following year, I obtained a multi-cart from Sean Kelly in Chicago with practically all the software ever released, plus I bought some newly-developed games from John Dondzila. It seemed amazing that a system that had been officially obsolete for more than a decade had suddenly come back to life. (In fact, more games have been made after its demise than when it was new.)

Then, back around 2005, an acquaintance gives me another Vectrex that he found at the tip. It was an American 120 volt model, and of course he had already plugged it in to 240v to see if it worked

Now it was dead. An internal fuse had blown. I replaced the fuse and powered it up using a stepdown transformer. I could get a white dot in the middle of the screen, so the monitor appeared to be working, but there was no sign of life from the computer.

Most of the computer chips were in sockets, so I carefully unplugged them one by one and tested them in my working British Vectrex. All of them appeared to work, except I couldn't test the CPU because it was soldered in place. I didn't want to risk damaging the working CPU board by unsoldering it.

As the CPU is obsolete, I couldn't simply buy another one and try it in the faulty logic board. I'm not 100% sure that a new CPU would fix the fault anyway, unless anyone out there has any ideas? That means sadly the second Vectrex has remained faulty to this day.
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Old 12th May 2016, 11:14 pm   #8
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Default Re: Vectrex

I didn't think the 68A09 was that hard to find. A 68B09 will work too (the letter indicates the highest clock speed you can run it at).

Have you tried using a logic probe to see the CPU is doing anything. Start with the E and Q clock lines. Then check the address pins and data pins. All should be toggling I think (maybe not some of the higher address lines).

For that matter have you checked the power supply voltages. According to the service manual the regulated supply lines are only used by the logic board. You might have a problem there.
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Old 13th May 2016, 12:05 am   #9
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Default Re: Vectrex

Thanks for the suggestions - I'll have another look at the unit sometime.

I vaguely remember there were some voltages present, but I didn't have the service manual back then. When I Googled the part number on the CPU, I only found one supplier in the UK who stated "Price On Application". When I enquired, it was about £30 plus VAT and postage, so I decided not to take the risk of ordering it only to find the machine still didn't work. Now it looks like there are some cheaper sources from China for the CPU if it does need replacing.
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Old 13th May 2016, 3:34 pm   #10
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Default Re: Vectrex

Unlikely the CPU, more likely to be the Masked Roms.
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Old 17th May 2016, 3:34 pm   #11
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Default Re: Vectrex

One of my Vectrex units needs a new controller,ive been faffing around with it for a while trying to repair it, but to buy a new one can cost almost as much as a complete unit.
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Old 17th May 2016, 3:43 pm   #12
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Default Re: Vectrex

If by 'controller' you mean the thing with a joystick and 4 buttons, then there are various designs around to use other games controllers with it. I have homebrew interfaces to use (a) Dragon/CoCo joysticks and (b) PC analogue joysticks (with the DA15 plug) on a Vectrex. There were other designs out there I think.

What is wrong with the unit you have? I assume the problem is basically mechanical because there isn't much electronics in one.
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Old 17th May 2016, 8:51 pm   #13
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Default Re: Vectrex

The actual joystick internals have disintergrated ,ive tried to fashion some replacements parts with little sucess.
i was actually going to see if i can find someone with a 3D printer to fashion the internals for me .
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Old 8th Jul 2016, 7:10 pm   #14
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Default Re: Vectrex

Picked up a roached Vectrex for £25 today, internals shot and blown but the joystick was pristine so solved the problem.
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Old 4th Sep 2016, 11:10 pm   #15
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Default Re: Vectrex

I've got one, had a mulitcart with all the games on but a house-proud wife, who had no idea what the little circuit board in a box was for, has seen it vanish Had mine since I was about 7 years old, still works great.
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Old 5th Sep 2016, 8:45 am   #16
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Default Re: Vectrex

I am intrigued by these, I didn't see (or at least I don't remember seeing) one in the 80's but I used to love the 3d arcade games.

I'm a bit baffled by the circuitry, there being just one 0 reference for both axes (which would move along the diagonal) and a "speed" for each axis how to work out which bit of the line will be drawn where...I guess clever use of maths and timing the blank signal right to get the right portion of the line? Too early in the morning to work it out.

I tried building something similar a while ago but I'm pretty sure I ended up with 4 DAC outputs. Will have to get me head round that circuit.

I'd be interested to see the 3d imager, I seem to remember the 3d tank arcade game at our community centre being quite convincing 3d but could rarely afford more than the odd go on it...

D
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Old 5th Sep 2016, 1:57 pm   #17
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Default Re: Vectrex

Quote:
Originally Posted by midlands_nick View Post
I've got one, had a mulitcart with all the games on...
I have one of those multicarts myself, they work on adjusting 4 jumpers within the cartridge, or circuit board depending on the option you bought originally, and they generally include demos of non released games and homebrew too.
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Old 5th Sep 2016, 4:34 pm   #18
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Default Re: Vectrex

I have one of these that I'd love to get working.

Would anyone here with an interest be able to guide me through the fault finding and repair process please?

I'm handy with a soldering iron, a 'scope and a DVM but I'm not that great at knowing what to check.


Cheers,

Andy.
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Old 5th Sep 2016, 5:19 pm   #19
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Default Re: Vectrex

I assume you have the service manual. You can download it, but I forget from where.

What, if anything does it do when you turn it on? Any sound? Anything on the screen at all?

Basically, I would start by checking the power supply voltages to the logic board. The unit will not work if those are missing. Also check CRT electrode voltages and see if the
filament is glowing.

Since this is a vector display the high voltage circuitry is not tied to the horizontal deflection. It's free-running. The CRT filament runs off the EHT transformer (looks like a line output transformer), so if that's glowing, the EHT side is doing something.

The digital side is a fairly conventional 6809-based computer. RAM troubles are common, as it uses 2114s. A logic analyser helps a lot in troubleshooting this side of things.

But anyway, let us (or me) know what it is and is not doing and we'll go from there.
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Old 5th Sep 2016, 8:41 pm   #20
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Default Re: Vectrex

Here is the service data

http://www.videogameconsolelibrary.c...rex-Manual.pdf
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