Holy Smokes! Tron, MCR, and Fried Ribbon Cables

Segagee

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Got my shiny new MCR Switcher adapter from Arcadeshop yesterday, and got around to hooking it up today. I did not purchase one of their power supplies, but I was told one I pulled out of an old computer could work, and the specs seem nearly the same. Just for reference, here are the specs of the PS I wired to the adapter:

115/230V selectable, 250W, +5V @ 25amps, +12V@ 10 amps. The supply also has -5 and -12 both at .5 amps.

So here comes the fun part: after wiring up the adapter, I set the PS in the cab and for testing purposes plugged the PS into the outlet in the bottom of the cab. I know I should not leave the PS like this, but the PS has a switch on it so it did not automatically cut on. I figure this was fine for quick testing purposes before I hardwired the PS into AC.

After plugging in the cab and turning on the PS, smoke started coming from the end of the board with the big power connector and one of my brand new (ARG, not like I have any more of these just laying around >_< ) ribbon cables burnt straight through.

The switcher adapter, however, did not smoke, and looks unharmed, so I'm thinking the issue is not with my power supply or switcher adapter.

I am also pretty sure I did not have the power connector or ribbon cables plugged in backwards, I quadruple checked them to make sure.

I still have the iso trans wired up, after disconnecting the PCB the monitor, marquee, and other lights still turn on.

Now I'm scared to turn the damn game on with the board connected again, not to mention I'm missing one ribbon cable. Any idea of what could have happened/what I can do to fix this would be awesome, thanks in advance.
 

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Got my shiny new MCR Switcher adapter from Arcadeshop yesterday, and got around to hooking it up today. I did not purchase one of their power supplies, but I was told one I pulled out of an old computer could work, and the specs seem nearly the same. Just for reference, here are the specs of the PS I wired to the adapter:

115/230V selectable, 250W, +5V @ 25amps, +12V@ 10 amps. The supply also has -5 and -12 both at .5 amps.

So here comes the fun part: after wiring up the adapter, I set the PS in the cab and for testing purposes plugged the PS into the outlet in the bottom of the cab. I know I should not leave the PS like this, but the PS has a switch on it so it did not automatically cut on. I figure this was fine for quick testing purposes before I hardwired the PS into AC.

After plugging in the cab and turning on the PS, smoke started coming from the end of the board with the big power connector and one of my brand new (ARG, not like I have any more of these just laying around >_< ) ribbon cables burnt straight through.

The switcher adapter, however, did not smoke, and looks unharmed, so I'm thinking the issue is not with my power supply or switcher adapter.

I am also pretty sure I did not have the power connector or ribbon cables plugged in backwards, I quadruple checked them to make sure.

I still have the iso trans wired up, after disconnecting the PCB the monitor, marquee, and other lights still turn on.

Now I'm scared to turn the damn game on with the board connected again, not to mention I'm missing one ribbon cable. Any idea of what could have happened/what I can do to fix this would be awesome, thanks in advance.

Sounds like you might have gotten a wire backwards. Double Check how you have it wired up.
 
Was the Tron set working before?

I don't think you can plug the power connector into the CPU board backwards, but if those are aftermarket ribbon cables (with 25 or 50 pins instead of 24), it is possible that they were shifted one over, sending some voltage to ground or something.

Can you confirm which connector and if they're 24/25 pin, and if the board was working before and this was a simple(!) upgrade?

I've been heavy into the back of the Tron recently after putting in a MCR power kit. I took the opportunity to test out a stack of boards and found that shorted capacitors on the sound board can smoke out an inductor on the CPU board and a fuse in a switching supply
!

Good luck-
 
Was the Tron set working before?

I don't think you can plug the power connector into the CPU board backwards, but if those are aftermarket ribbon cables (with 25 or 50 pins instead of 24), it is possible that they were shifted one over, sending some voltage to ground or something.

Can you confirm which connector and if they're 24/25 pin, and if the board was working before and this was a simple(!) upgrade?

I've been heavy into the back of the Tron recently after putting in a MCR power kit. I took the opportunity to test out a stack of boards and found that shorted capacitors on the sound board can smoke out an inductor on the CPU board and a fuse in a switching supply
!

Good luck-

Unfortunately I have yet to see this boardset working. When I got the game the original linear PS had gone bad and no power was being supplied to the board; the guy I got the game from said the game just started showing a white screen one day so I assumed the PS was bad and board was still in OK shape. Tried fixing this before purchasing an adapter with no luck.

Yep, the ribbon cables are aftermarket. They are the ones from Bob Roberts, Dual Row 25 pin. Only one smoked so perhaps I missed a pin somewhere when connecting them. I still have the old ones sitting around, maybe I can at least use one of them to replace the toasted one.

There seems to be no physical damage on the board; I was also checking the caps around the area that smoked and they still tested good on my meter but maybe they still have a short?

After checking the wires to the switcher adapter again, they were all correct, but one of the ground wires was not attached. I'm pretty sure this happened after the board smoked, but could this wire being disconnected cause a short or something?
 
I don't think I smoked the board, the components still seem to check out ok and there is no physical damage/burns apparent.

Fired up the switcher adapter and the LED lights fine, PS runs, so I am pretty sure the problem may have indeed been being one pin off on the ribbon cable; can't believe I did this. Hopefully one out of the five old ones will work.
 
Those cables suck -- I hate them! :)

The dual rows and extra connectors are touted as 'features' but they are a royal PITA!

Give me ONE row and a 24 pin connector that's not quite so wide and they would have been much easier to install.
 
*VG wipes a small tear from his eye*

Don't cry vintagegamer, the good news is the board isn't fried and I finally got it up and running today! I used 4 old ribbon cables and one new one and the game booted right up. Sounds, controls, and everything work too. Of course with my luck I have run into another slight problem.

The image on the monitor looks nice and crisp after I adjusted the flyback brightness, but certain sprites do not show up. So far I've noticed the cursor in test mode, tanks, light cycle grid, light cycle bikes themselves, and MCP cone in attract mode are not showing up. Going to do some research, anyone have any ideas? Bad chip(s)?

Sorry for lack of pics, have to rush into work here in another 15 minutes.
 
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I cut a couple of these cables from an 8-way SCSI cable for my Berzerk machine. Turned out I didn't need them in the end (I've got good original cables) but I did misplace one of them one time. Luckily the game just didn't boot and kept like crashing but no smoke etc.

You have to triple check if you go for this solution. It's ok when you have the machine and don't change around boards very often any more, but I was at the moment...
 
Got the grids in the background to show up, realized I had the brightness on the fly turned down a little too much. I also found out I can adjust the infamous distorted line of pixels toward the bottom right of the screen with Vsize as I've read there is no actual fix for this.

Still missing sprites/graphics, however. On the "enter the MCP cone" screen I could not see anything other than the high score letters up top. Grid bugs, tanks, and the actual light cycle bikes, and test mode cursor are still missing.

Figure I will try to clean and reseat the ROMS/RAMS for starters; if anyone knows any specific ones that could be causing this issue that would be a big help. I looked over the TRON and MCRII manuals for info but the schematics are a little over my head.

Pretty sure my ribbon cables are on good but I will double check those too, maybe one is loose or something. Could one of the cables be bad and the game still display 90% correctly?
 
What always bugged me was the lack of info regarding which ram chip locations affect which sprites. I never found this info for tron or spyhunter. Its something you have to figure out yourself through messing around with your boards and trial and error. Why is this info kept so secret?
 
The sprites all come from the Video Generator board, which is the board closest to the outside of the cabinet. Try reseating the chips on that one. The backgrounds come from the CPU board in the middle.
 
The sprites all come from the Video Generator board, which is the board closest to the outside of the cabinet. Try reseating the chips on that one. The backgrounds come from the CPU board in the middle.

Yes. But why is this kind of info and other more detailed info so hard to find in written form from the original programmers and manufacturers, and game experts. I know there must be detailed files on all these games that are in archives somewhere. I would love to look through the programmers notes for individual games I own.
 
unfortunately, unless someone like atariscott comes up with a whole shitload of hidden bally/midway notes and documents, i doubt you'll ever see any detailed info, aside from possible repair logs or by talking to people that do a lot of mcr type repairs.
 
If a guy had some free time, you could individually corrupt each ROM image in MAME and take detailed notes of the results. I think that would be more accurate and safer than trial and error on real hardware. We need to find someone with swine flu or a broken femur that's looking for a project.
 
If a guy had some free time, you could individually corrupt each ROM image in MAME and take detailed notes of the results. I think that would be more accurate and safer than trial and error on real hardware. We need to find someone with swine flu or a broken femur that's looking for a project.

That's not actually too hard to do...

Here is how Braze did it for DK:

http://www.brasington.org/arcade/tech/mame.shtml
 
The sprites all come from the Video Generator board, which is the board closest to the outside of the cabinet. Try reseating the chips on that one. The backgrounds come from the CPU board in the middle.


Thanks for the tip, cleaned this board thoroughly, removed, cleaned, reseated the chips and am still getting the same results and am trying to think of what to do next.

I also tested the chips for continuity on the video generator board and they all check out ok; apparently this means little though. Just figured I would do it for the hell of it because I have no means of extensively testing the chips.
 
id go back to another set of cables..


my tron was missing stuff untill i got fresh cables on it..

you just have to use a meter and like some old cap lead to verify how the cables are wired...

ive seen them be onee pin off on one side, and my big problam was having a few cables that the top row would be hooked up on one side but the bottom row would be connected on the other...
 
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