Robotron/Joust Cab Log

MartyMcfly

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I've had a non-working Robo cab for about 3 years now. I kept poking at it here and there but didn't do any serious work. Mainly because I'm learning all this stuff.

Back in Feb I started focusing on the power supply. One thing I've learned about this hobby of mine is that me and PS don't mix. A few of you's can attest to my incompetence ;) So I start poking around with my multimeter and end up cross shorting the PS. I actually started a little fire, I had smoke and everything and even fried one of the IC's. It was a real beaut you shoulda seen it!

So I 'cold call' LaserRot out of nowhere and ask him if he could rebuild my PS. Great guy to deal with BTW. He has the thing repaired the same day that he received it and shipped back out. Total time was about two weeks. Thanks again LaserRot!

As soon as I get the PS back I plug it in and sure enough this cabs that's been sitting there for years starts up! I coined up and had a running machine!...well not exactly. The monitor needed adjusting and the controls simply wouldn't work.

I adjusted the monitor the best I could and had a half decent image. VectorCollector's recommended that I rebuild the chassis. I will at some point in the near future (way before the year 2084.)

I adjusted the leaf switches on the controls and got some basic fire/movement. The controls are not perfect but I've been actually playing games these past few weeks and am starting to like the game.

After doing some research I learned that Joust shares most of everything with Robotron. Which is pretty awesome because Joust has been at the top of my short list for a while now. Even awesomer is that I have a spare Joust boardset as well as an additional tested and working Robo boardset.

I actually tested the Joust sound board and is confirmed working. BUT when I was pulling out the connectors for the sound card I yanked out a black wire from one of the connectors.

Can anyone give me a quick tip on how I can reconnect the wire to the connector? Do I use a standard crimping tool? When I look inside the connector it has some alligator teeth, and it looks like I can just slide the wire in between the two teeth.?
 
The original connectors were IDC. You'll want to get a .156 Molex housing of the necessary # of positions and crimp pins.
 
thats an IDC (Insulation Displacement Connector) and they suck. :) The proper tool puts pressure on the wire jacket on either side of the tin connector so that the jacket gets pierced and the wire makes contact. You can try using a small flathead and force the wire down on each side of the tin, that should be enough.
 
joeycuda's idea is actually a good one. Those IDC's are junk. get the connect sized molex connector and .156 trifurcon(sp?) pins.
 
re-pin

+1 on the re-pin. It will help. Start with all the power connectors. When you get the hang of it, it's not too hard. Just time consuming. Try great plains for connectors.
 
- Quick fix, punch the wire back down on to the IDC connector with a screwdriver.

- Long term, replace ALL the IDC connectors and re-crimp with pins and replace with new connectors
 
and don't pull the plugs out by the wires, ever. IDC or molex.

I've been seeing more and more of these games lately losing a ton of voltage between the power headers and the actual chips. the MPU and rom boards in particular have filter caps, and they're old, and that's where the voltage loss is coming from. had a Joust the other day getting 4.88 at the header but only 4.12 at the chips, and that's with both the un-rebuilt linear board and a switcher with adapter. they're 100 uf/25V, 5 in all between the two boards.

the factory headers were also garbage. I didn't go 200% OCD with those, I only replaced the power ones on the MPU and rom boards, as well as replace the original IDC plugs with molex. those were the only ones I redid with molex, however the coin door input plug to the rom board on our Stargate was redone with molex cause the Auto Up button wouldn't work!

chicken or egg argument over which power supply to use; the reality is the games were designed to taper off voltages in a specific order, and the switchers essentially have it backwards. I didn't experience any CMOS corruption on our games when I was diagnosing the boards running switchers, but I've seen a lot of games that do. I suspect this is why Galloping Ghost Arcade uses credit switches on their games cause I know they're proponents of switchers and if the CMOS pukes their games still work the same way.

I did extensive work on our linear power supplies. if you want a checklist of parts you'll need to redo them correctly I can provide that. I just don't know if coming from Canada if you'd be buying from Great Plains Electronics, cause those are the parts numbers I have.

additionally, the ribbon cables on the rom and input boards die frequently. never grab those by the ribbons. the input plug you can easily grab the plastic housing; the rom board I found you can alternate sides pushing the connector out with a 90 degree pick. that's one way to not abuse the ribbon.
 
I'll eventually get back at the sound issue. I like the idea of .156 Molex housing.

I bought a rebuilt CRT from Delroy666 (Thanks again Dale). After transplanting it I still have the focus issue. Still, with a rebuilt monitor and the original I end up with a spare working one!

I've been tackling the control issue on and off. The game would fire or move in all directions. I re-soldered the wires at the controls and had a bit better results. Some movement/fire directions were intermittent. So I did a bit more research and tonight I re-flowed the connectors to/from the widget board and now I have more consistent fire/move.

Current issues:
-Lack of focus. I've adjusted the focus on the flyback(s) but the best I can get still looks blurry.
-I have to coin-up twenty times in order to play a game. When I do play I get a dozen lives.

Once I'm happy with Robo, I will tackle the Joust portion. The control panel that I got is missing the bottom wood panel (where it bolts to the machine). I saw a KLOVer here with the repair log so will follow that.
 
Update since June...June Really?

Anyway.

I still have the focus problem even though I've reflowed the connectors from the vid board twice. Obviously I'm missing something since I have a spare vid board and have the exact same issue.

Any guidance would be appreciated.

I no longer have issues with the controls. I can thank the reflow for all joystick connectors for that.

I bought a broken control panel from Linkage this past winter. The control panel is fully populated but was missing the bottom wood panel. My woodworking skills are even worse than any other arcade skills that I have(except for selling shit). My wife's cousin is a carpenter I gave him dimensions and he made an exactly matching piece so I'm pretty happy with that.

So now with Robo sorta working and a tested/working Joust sound card. I now get "All Systems Go" message from the Joust ROM card and then it craps out. It looks like a 'u' on the ROM's LED diag light. I've researched that it could be the CPU, the special chip or just the ribbon cable. I have a spare ribbon cable but find it's quite the bitch to desolder the connector. All solder looks like it's been removed but I'm not quite sure how to pry it off.

Once again, any guidance would be appreciated.
 
I have a working spare Robo ROM board. Can I swap the ROMs and special chips from Joust's?
 
I have a working spare Robo ROM board. Can I swap the ROMs and special chips from Joust's?

dont need to swap the specials. Only need to swap ROMs but you need to look at both boards to make sure they are strapped for the same type of ROM. If one is 2532 and the other is 2732 then you need to move jumpers too.
 
I swapped out the ROMs and to the spare Robo board and no luck.
I know it's not the ribbon cable because the spare worked with the Robo chips.

Can I assume that it's the ROM's that are toast?
 
funny, I pulled the rom boards out of Robotron and Joust at work cause I need to upgrade roms. these are the boards side by side, they appear to both have 2732 roms, I think that portion of the cap/zero ohm resistors in the lower left are the jumpers. make sure yours are set the same between boards.

I strongly recommend using a desolder vacuum tool like the Hakko FR300 if you intend on replacing ribbons. I can do them very fast now and they almost just fall out. don't force them cause you'll rip traces on the component side easily. just keep adding new solder and try to desolder. I personally grab the pin and spin it around while using the sucker, it theoretically should get all the solder around it. use a tiny flathead or fine pliers to wiggle the pins; if they don't move or pop from the remaining solder, then you didn't get it all out.

I've never seen a u code on not-Sinistar games. the CMOS can be corrupt, you can try pulling batteries out and see if it forces a factory reset. this is particularly problematic with switchers.
 

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6821 PIA is a common failure and controls the signal to the LED on the ROM board. It will also give you dead game symptoms as it sits on the processor bus.

Good Luck!

Kirk S.
 
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