Game Plan MPU-1 Repair

To run this board on the bench you need the following.

Connector J1(top right 15 pin)

Pin 14-15 Ground

Pin 13 +12

Pin 11-12 +5

See the first video in this post on how to trick the board into getting past the first flash.

Repair notes part 1. Jumpering board for 2716 roms.

Putting some information I've learnt while working on these Star Trip Cocktail Pins. It's really hard to find any solid information on these boards that has clear instructions on how to work on them. Most I've found is on the Gen 2 board.

Important Information.

RAM

Gameplan Gen 1 boards use 2 6551 cmos rams. There is a socket for a 2810 ram but is not used for Star Trip which is lucky because all the boards have bad corrosion damage in this area.

Gen 1 boards will not boot with any flashes if the 6551 cmos rams at U6 and U7 are bad. In my case ALL the rams on all 5 boards except 1 were bad. I was able to get 1 flash with the only good ram I had in U6 however after the board was modified to take 5101 rams I could not get any flashes without both 5101 installed. I found the information on the wiki hard to decipher and VERY confusing on how to convert the board to take 5101 rams however I managed to work it out (coming up in Part 2)

ROM

A DIY adapter to read 2316 roms as 2716 can be found HERE

In my case ALL roms were bad and only 2 I could get data out of that even closely resembled what they should be.

Reset Circuit.

Felt right at home with the reset circuit. It's almost identical to the Berzerk Arcade boardset I recently worked on. I'll be doing a write on a mod I did using a Mcp120 soon.

So yeah I had a hard time getting a board working because I had no working reference board and I had no idea is any of the components were any good.

Converting Gen 1 to take 2716 roms.

The schematics are pretty cryptic on how to do this but I eventually worked it out.

Cut the circled traces and jump a wire from pin 24 to 21. This pulls VPP high.

Install circled jumper and cut circled trace. What you are doing here is separating the OE between U12 and U13. U12 remains connected to A11 on the CPU while U13 with 1 more jump will be connected to U5 Pin 11.

The Jumper connects Pin 20 on U12 and U13 to Pin 21 (RD) of the Z80 CPU.

Final jump is below the 74ls32 U5 above and connects to what I wrote above.

That's it your board can now take 2716's.

Part 2 - Converting board to take 5101 rams.

Why would you want to do this?

Apparently 6551's are hard to get and its absolutely essentially both the rams work for you to have any chance to get one of these boards to boot regardless of what the manual says about what diagnostic flash means what.

This tripped my up for days because A.it turned out all but one of the 6551's on all the boards were bad and B.the Wiki was next to useless.

[ATTACH=CONFIG]157557[/ATTACH]

Cut trace on U6 and U7 between pins 18 and 19. This this also breaks the track between pin 19 between U6 and U7 and will have to be repaired.

[ATTACH=CONFIG]157558[/ATTACH]

Run a wire between Pin 19 (CE1) on U6 and U7 this goes to pin 6 of a 74s32 @ U9. Depending on how bad the corrosian is you'll probably have to run the wire right down to the 74s32 Pin 6 which was the case here otherwise just run a jumper between pin 19 on U6/U7.

[ATTACH=CONFIG]157559[/ATTACH]

Next Pin 18(OE) needs to be wired to Pin 21 (RD) of the Z80 CPU. The easiest place to get the signal is from the jumper we installed just under the rom socket U13.

The last and most annoying step we need to invert Pin 17(CE2) of the 5101 using a 74LS04. Seeing as there are no spare inveter pins to use on the board we need to add a extra IC in.

[ATTACH=CONFIG]157560[/ATTACH]

First cut the track on U5 74ls32 Pin 8 as shown.

[ATTACH=CONFIG]157561[/ATTACH]

This step we have to add in a 74ls04. I've mine it where the socket for the 6810 would be. You may have to piggy back it on top of another 14 pin IC like the 74ls00 at u4 or 74ls32 at U5 it all depends how bad it damaged the area is where the 6810 socket sat which in my case bad to the point you can't even melt the solder and desolder most of the pins. If you can at least get the hole for pin 24 out we can use that as our +5 for the 74ls04(pin 14).

[ATTACH=CONFIG]157562[/ATTACH]

Bend up all the pin except pin 14. Cut off pins 8-13 (not needed) and trim pins 1-7 as shown in pic. Insert Pin 14 of the 74ls04 into 24 of the 6810 through hole and connect pin 7 to ground, I used the big ground trace shown in the pic.

We'll be using pin 1(input) and 2(output) of the ls04

[ATTACH=CONFIG]157563[/ATTACH] [ATTACH=CONFIG]157564[/ATTACH]

Run a wire from U5 pin 8 to Pin 1 on the 74ls04. You can run the wire through the holes as shown. You'll probably have to drill them because you just can't melt the solder. Don't worry about damaging the plated through hole. This is the area where a socket for the 6810 would sit, its not used and never will be and is too damaged to worry about anyway.

[ATTACH=CONFIG]157565[/ATTACH] [ATTACH=CONFIG]157566[/ATTACH]

Last step is to run a wire from pin 17 U7 to pin 2 of the 74ls04.

Congrats your board is now set up to run 5101's

Now here's a as little presentation on YouTube for everybody to barf at which shows you the board flashing and how to trick the Zero cross to think there is 24 volts.

If the board in the second part of the video looks like a glazed doughnut it's because it's had a good coat of PCB lacquer.

Nice bit of modding. Well done.

Thanks mate.

Finally got one of the boards booting today so pretty chuffed. Thought I'd better write it down while fresh in my mind.

This is why you are Arcade King :cool:

Really good idea in documenting this.

Were you able to read the original roms and transfer them?

And how about the ram chips, did you manage to get replacements?

 

Sorry, I see there is a part two, looking forward to following this.

The forum is good to write down repair logs rather than using notepad, I find myself coming back often looking at my old logs. I found the wiki very confusing, A lot of mods are shown for Gen 2 boards however no clear explanation is given to why a trace was cut and why jumper X was installed so I'm trying to make this as simple as possible to follow.

Luckily the roms were available on IPDB https://www.ipdb.org/machine.cgi?id=3605 I would have been screwed if they weren't.

Fun fact. There was another game called "Family Fun" that uses exactly the same playfield and roms as Star Trip.

https://www.ipdb.org/machine.cgi?id=817

Part 2 - Converting board to take 5101 rams.

Why would you want to do this?

Apparently 6551's are hard to get and its absolutely essentially both the rams work for you to have any chance to get one of these boards to boot regardless of what the manual says about what diagnostic flash means what.

This tripped my up for days because A.it turned out all but one of the 6551's on all the boards were bad and B.the Wiki was next to useless.

Cut trace on U6 and U7 between pins 18 and 19. This this also breaks the track between pin 19 between U6 and U7 and will have to be repaired.

Run a wire between Pin 19 (CE1) on U6 and U7 this goes to pin 6 of a 74s32 @ U9. Depending on how bad the corrosian is you'll probably have to run the wire right down to the 74s32 Pin 6 which was the case here otherwise just run a jumper between pin 19 on U6/U7.

Next Pin 18(OE) needs to be wired to Pin 21 (RD) of the Z80 CPU. The easiest place to get the signal is from the jumper we installed just under the rom socket U13.

The last and most annoying step we need to invert Pin 17(CE2) of the 5101 using a 74LS04. Seeing as there are no spare inveter pins to use on the board we need to add a extra IC in.

First cut the track on U5 74ls32 Pin 8 as shown.

This step we have to add in a 74ls04. I've mine it where the socket for the 6810 would be. You may have to piggy back it on top of another 14 pin IC like the 74ls00 at u4 or 74ls32 at U5 it all depends how bad it damaged the area is where the 6810 socket sat which in my case bad to the point you can't even melt the solder and desolder most of the pins. If you can at least get the hole for pin 24 out we can use that as our +5 for the 74ls04(pin 14).

Bend up all the pin except pin 14. Cut off pins 8-13 (not needed) and trim pins 1-7 as shown in pic. Insert Pin 14 of the 74ls04 into 24 of the 6810 through hole and connect pin 7 to ground, I used the big ground trace shown in the pic.

We'll be using pin 1(input) and 2(output) of the ls04

Run a wire from U5 pin 8 to Pin 1 on the 74ls04. You can run the wire through the holes as shown. You'll probably have to drill them because you just can't melt the solder. Don't worry about damaging the plated through hole. This is the area where a socket for the 6810 would sit, its not used and never will be and is too damaged to worry about anyway.

Last step is to run a wire from pin 17 U7 to pin 2 of the 74ls04.

Congrats your board is now set up to run 5101's

Now here's a as little presentation on YouTube for everybody to barf at which shows you the board flashing and how to trick the Zero cross to think there is 24 volts.

If the board in the second part of the video looks like a glazed doughnut it's because it's had a good coat of PCB lacquer.

Part 3 will be replacing the reset circuit with a single MCP120-450.

First post updated with this post and extra info about running these boards on the bench.

Have you seen this repair guide,its more to do with the MPU 02 but might be helpful

http://https://pinside.com/pinball/forum/topic/game-plan-mpu-repair-a-shotgun-guide-w-pix

Thanks mate yeah that's the first thing I found unfortunately as you said more about MPU-2.

The information I've provided so far has been cobbled together from several sources but mostly working it out for myself.

I got a couple of the boards working now, I just need the time to document the rest of the mods I've done.

Edit: @GIBO sorry mate we must have been editing your post at the same time to fix the link. For some reason I saw 2 of the same posts and deleted one and now both are gone.

From a collection point of view it's just a fun novelty item that's going to look great in any games room. I don't think anybody would expect anything more than a the novelty value.

At this point its about getting the electronics reliable. I don't usually mix work with the forum but I thought this may be of interest to somebody.

Been a long time since I've updated this thread.

I was thinking about ways to make these games as reliable as possible and a Nvram/Fram solution is just the thing needed. I came across @Tangles Stern MPU-200 5101 replacement board.

After a few hours playing around with my breadboard and a FM16W08 64k Fram I'm happy to report I've successfully modified this Gameplan MPU to work with Tangles board which I might add is far easier than modifying it to take 5101's. I'll now be able to design and make a drop in replacement that requires no modification of the board what so ever.

The benefits will be a more reliable board with no batteries, adding in the extra inverter no longer needed and getting the rest of the corroded MPU's up and running...I hope.

I've got this game working and all lamp, solenoid and switch tests pass, I can even start a game.

So progress :)

Here's the Gameplan MPU1 (should work in 2 also) drop in replacement ram board I doodled in EasyEDA. I've sent it off to get made so looking forward to seeing how it goes.

and here's my first Gameplan drop in CMOS ram replacement board I just put together...and it just occurred to me I should proof read stuff before getting it manufactured.......oh well this batch can be called the special LE edition not that any more will be made unless somebody asks me specifically.

As aforementioned this is a drop in replacement no modifications required however I do recommend cutting the trace to the rams from the unregulated 5 volts and joining it directly the the regulated 5 volts to avoid any weird behavior.

I'll document this down the track.

And Finally here's a short video of Tony playing the finished game. Sorry about the glare from the rooms lighting.

I think I put 150+ hours into the research and repair of this machine's boards and PSU.

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Also I'm starting to put together some more AKRAM @Audioenslaved and version 2 of the Gameplan Ram replacement board from the last post with correct spelling. I also mixed up the A4 and WE lines so I had to remake them anyway.

Second Gameplan MPU is 100% finished tested and working.

This ones got the modified reset circuit and my drop in Fram replacement board, no batteries EVER!.

So pleased with how this came out and hopefully will run for many years to come. That Fram adapter I made should make getting the others a lot easier to get going and saves a lot of hacking of the board.

I'm going to give myself a well deserved pat on the back for this one :D

Yeah the did get made and work as the above post but I didn't expect anybody would want one.

There wouldn't be enough room for the DIP version of the Fram.