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I just passed one up today, and I am still not sure it was the right decision.  :darn:

Yesterday, I saw an ad on craigslist for old school arcade games as the title. It was at the top of the list, so I know it was recently posted. The ad was for Robotron and Asteroids and all it said was Best offer and a phone. about 15 miles from my home.. I called immediately and got the answering machine. I leave a msg, and am anxiously awaiting a phone call. Finally, I'm on my way home, and my phone rings... its my machines calling... I really want Robotron. So the guy says he's had them for about 10 years and he bough from a dealer.. Everything works great, hasn't touched in awhile, and needs the space. I asked what price he had in mind, and he says $250.. I said Robotron is SOLD! I'll take it. He said the same price for Asteroids, so I made some phone calls, and found someone to take the Asteroids as well. He said he'll clean them up and have them ready for me. We make arrangements to pickup on Sat. I called him this morning for directions, and he says the monitor on Robotron stopped working, and fades in and out. I start to whine a bit, but decided to continue as planned and hopefully get an even better price. I got to the house, and these are in gorgeous condition... nicest I think I've ever seen. I start looking at Robo, and start wiggling some wires, and the monitor starts to show life. The game took forever to work, but after about 5 min, a test screen pops up and says Rom error. We rebooted the machine a few times, and no luck. The guy was only willing to knock $50 off it. I walked away without the machine. I was kinda hoping to have him flag me down before I drove off, but it didn't happen.

Sorry for the ramble..  :down:

Give him a day to sit on it and call him back tomorrow with a $100 offer... And remind him he won't sell a non working machine to someone who doesn't know how to work on them...

You might still get em?

I thought about doing that. HE and his buddy were there, and they mentioned something to each other about knowing someone that may be able to fix the board. I still may give it a shot.. I really want Robotron :biggrin:

200 bucks is a good price for a clean Robotron.  Those early Williams games are famous for eating up the 4116 rams.  It's usually because the power supply gets old and doesn't output nice clean voltage anymore.  Replacing the PS with a switcher and replacing the rams usually does the trick.  Another williams problem is the board interconnect get flaky, that will give rom errors also.

Are the 4116 ram chips readily available? The lcd on the board was giving a few codes, but don't quite remember what they were right now..

Hi Ken
  Give me a shout about the Robotron, I have a buddy up in north Jersey who works wonders with the older boardsets.

Thanks Tom.. I'll give you a shout midweek. I think I'm going to give this guy a call and see if he still has it...

Well, this has been eating away at me.... I sent the guy an email, and he still has the machine. He said someone was supposed to show up 2x already and hasn't. I think I am going to have to pick up the game this weekend at some point. My wife isn't thrilled, but are they ever?? :biggrin:

Well, its home. I'll get some pics soon. I spent a few min on it last night, and I think I have a PS issue. i also think someone has tried to fix this thing since last time I was there. I didn't plug it in when I picked it up, but I looked quickly to see if it was still complete. I noticed on the power supply board that one of the molex connectors burnt up, so someone did a Mickey Mouse solder job on a few pins.. I let that fly, but I am not currently getting any +5v to the video/cpu board. The wire with no voltage was pulled out of the harness like someone was following it. When I was there last time, the game powered up and had errors. Now it powers up and I get sound when I hit the test button on the sound board, but nothing from the cpu. I'll have more time later today to get deeper in too it.

I also pulled the PS board, CPU board and RAM board looking for bad solder joints, and I found 2.

Looks like its definitely a bad power supply to start with. Unfortunately, I don't have a donor to put in, so I have to wait till I get one... Anyone have a Williams Power supply? I don't need the board, but do need the transformer...

Most people nowadays use a switching power supply.  Arcadeshop has a switching PS Robotron conversion (http://www.arcadeshop.com/parts.htm#Power) (about half way down the list) for $39 (I'm pretty sure you get the adapter and PS).  The switching ones are better than just a transformer since you can adjust the output.

Thanks doc.. I'll give that a shot. It doesn't show any adapters in the photo. I'll check it out. I hope thats all that is wrong with this machine..

The Arcadeshop ps kits come with the adapter also.  The 4116 are available from arcade shop also.  I think they are like 24 bucks a set

So this takes the transformer board out, and the dc board as well. The 3 other molex connectors connect to this adaper. I'll order the ram as well. Hopefully, that'll fix the whole game... I can't wait to play this game...

If your lucky that will fix it.  You will probably end up repair all the board interconnects as well.

Another good source for parts help is Bob Roberts  http://www.therealbobroberts.net/  A old timer who knows his stuff and is about the nicest  guy in the world. 

There is a website out there that really details repair/mods to the old Williams boardsets.  I can't find the link in my piles of garbage but will look around and see if I can locate.

I went through the board connections already and reseated the wires and connectors. I hate those wire pierce connectors...

Bubba,  Here's that website.  Can download manuals, has plenty of good tech stuff also

http://www.robotron-2084.co.uk/

Thanks for the info.. I can't wait to get this game running.. The more I am reading about this, the more I think these 2 items will fix everything.  I did come across some info on this UK site for using 4164 ram instead... have you ever seen it or done it? It doesn't look horrible to do...

No I haven't ever seen/done the ram mod.  The other ram is still available so I've never bothered.

I am on a roll.. Robotron is working... I just got the PS and RAM... Had a few issues with, but persistence paid off. I ended up being into the game for $250 just as if I would have purchased it from the guy working.. Thanks for all the tips to get it working... (http://www.groelfamily.com/ken/smilies/beerchug.gif)

Awesome,  play a couple games for me.  Robotron is one of my favorites and I haven't played on in a couple years.

Congrats on the Robotron, I agree that its a really cool game...

Frank

Well, no good deed goes unpunished. I was cleaning up the machine, and putting the finishing touches on the wiring, and to make a long story short, I let the smoke out of the circuit board for the monitor. Still not sure exactly why, but it has something to do with the lights on the cabinet. I have a monitor in my Bad Dudes game that is in good shape, and I am in the process of swapping it out now. I discharged both monitors using the screwdriver and ground wire method, but neither one popped or made any noise at all. I felt like I was dealing with a fuse that didn't light a firework. Anyway, I got the new monitor and board mounted in the chasis, and I noticed on the new monitor a tag that says isolation transformer must be used. The power supply I installed is a switching power supply. Do I still need to use an isolation transformer? Can I hook up my cabinet light? I don't want to blow another monitor....

The monitor that I took out is a WGK4625, and the new one going in is a WGK7062.

One more thing... I did fire up the machine, and the monitor comes on. The display is mirrored.. The new monitor was connected to -H & -V sync in the old game I removed it from. The old monitor just says H & V sync, but doesn't say +/-. Would this invert my image? I am treading lightly on this since I don't want to kill 2 monitors in one day...

I'm getting there... I got the image corrected. I needed to use the +H/V sync. Then the image was upside down. The wires for the yoke can be flipped to correct that.  So now I am about 95% of the way I had it last night... Just have to figure out how to adjust the Horizontal size... fore some reason, I can adjust Vertical bot not horizontal size....

Yes Bubba, if it says it needs an iso it needs one.  Most Power supply conversion kits keep the isolation transformer in place.  I can't imagine you took yours out, it's usuallly the first thing in line from the line cord.  From the isolation transformer it goes to the monitor, cabinet lights, power supply etc.

 I took out the transformer since it was throwing out low voltages all around. I thought this new power supply was taking the place of the transformer as well as the DC conversion. I wired my power cord directly to the new power supply. So, next time the circuit board it the only thing to get replaced? I have the original transformer board with what looks like a start capacitor....
right now, the only thing the 110 feeds is the monitor. I guess I need an iso to get the marquee to light up.. Also, according to the wiring diagram, the power supply board puts out 6.3VAC to the lights for the start button, and 27VDC that has something to do with something else trivial. That whole plug is disconnected right now. Any idea what to do with those?

I have learned a whole lot on this game.. even with my mistakes, I still think it was worth it. So far, I've troubleshooted a non-working game, and made it work. I blew up the monitor by a mistake, but I learned how to discharge a monitor. and swap it out. Then I learned how to flip the wiring on the yoke to change the image reflection. I also learned not to use a steel allen wrench to adjust the horizontal size. I may need to replace the horizontal coil on the board to get my adjustment now... I didn't get hurt, it cost me a few bucks more than I was hoping for, but I am still ahead on value. And I got Robotron :biggrin:

It's been awhile but I think 27vdc is for the coin door lights on the older williams games.I usually don't even pull the old power supply out.  I just leave it in and there is enough slack on the wiring harness to zip screw the switcher behind the old one.

I'll take a pic of the whole power supply that was in the game originally. There are a few components on the board that I am not sure about. The Transformer itself was putting out a few low voltages, so that is why I removed it. I thought the switching power supply was supposed to work the whole machine, especially since it came with an adapter card to use the existing plug off the dc board.

Bob Roberts site showed a few voltage conversions.. one for the player button lights which are normally 6.3v making it 12v and something on the coin door.

I have a Stargate and Joust, both are powered from switchers and on both have the 6.3 vac and +27 disconnected.

I also cant remember what they are used for.  Machine can run fine w/o them..

FB

PS My Stargate is acting up.. If anyone has a ROM board for a Stargate, I would be interested.

Frank.. do you have the iso hooked up also? The 6.3vac is for the lights on the P1/P2 buttons. I want to get this done today so I can get my basement back together... I've got machines and tools all over the place..

On both machines, monitors are still powered through the iso.  I have attached some pics of how my switcher is hooked up.

1st pic is how my switcher is mounted, PS board and heat sink were removed, switcher on plate.  The green and white wires are going to power block and power the switcher.

The 2nd pic is my power block,  you can see how the ground and hot wires (green and white) are attached.

You can also see a 12pin molex connector coming out of block, 2 of these wires are going to monitor for power.

They look like either brown/yellow or purple/yellow.

Hope it helps, pics are not great, it was a little tight.

Frank