Millipede board issue

reboot

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Donor 2012
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Hey all,

I picked up a non working Millipede cab and I had some spare time to work on it today.

What it is doing (or not..)

This is the game play



In test mode


The game will coin up and play for about 15 seconds and acts like it restarts and I can then coin up and do it over again.

I forgot to write down the voltages but the board is getting 5.0 VDC,I will re-test tomorrow. Cleaned and reseted edge connectors.

I have cleaned and reseted all removable chips and same issue. Any ideas on what I should look at next?

Thanks in advance!
 
Probably the line buffer ram is bad at location 8B. IIRC it is a 93422 ram chip. I don't think it's socketed.

Brian
 
Probably the line buffer ram is bad at location 8B. IIRC it is a 93422 ram chip. I don't think it's socketed.

Brian

I will take a look there and see,thanks for the info.

Looks like I will be needing to send this in for repair as I don't have a probe or a scope(yet)
 
Hey all,

I picked up a non working Millipede cab and I had some spare time to work on it today.

What it is doing (or not..)

This is the game play



In test mode


The game will coin up and play for about 15 seconds and acts like it restarts and I can then coin up and do it over again.

I forgot to write down the voltages but the board is getting 5.0 VDC,I will re-test tomorrow. Cleaned and reseted edge connectors.

I have cleaned and reseted all removable chips and same issue. Any ideas on what I should look at next?

Thanks in advance!

Boards that reset are usually power problems. The power supply is flakey or a chip is failing/shorting and causing the voltage to drop untill the board resets itself.

After taking off all jewelery from hands; Feel around the game pcb for hot chips and test the chips for voltage and maybe watch for the chip voltage to drop (using your volt meter).
 
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Boards that reset are usually power problems. The power supply is flakey or a chip is failing/shorting and causing the voltage to drop untill the board resets itself.

Fell around the game pcb for hot chips and test the chips for voltage and watch for the chip voltage to drop.

I did watch the voltage while it was doing this and it never moved off 5.0VDC on the game PCB...but I did not check chips for heat or stick the probe on the chips. I will check that.

As for the PSU it tests fine and I also tested this board in my Centipede cab(which works :) ) and the game PCB did the same thing.

I need to build a test bench...
 
I did watch the voltage while it was doing this and it never moved off 5.0VDC on the game PCB...but I did not check chips for heat or stick the probe on the chips. I will check that.

As for the PSU it tests fine and I also tested this board in my Centipede cab(which works :) ) and the game PCB did the same thing.

I need to build a test bench...

Just try to locate and see if any of the chips get real hot. I mean hot the ram chips will get warm but not hot.

If you can't find any and don't have the tools then you might just send out for repair.
 
Just try to locate and see if any of the chips get real hot. I mean hot the ram chips will get warm but not hot.

If you can't find any and don't have the tools then you might just send out for repair.

Will do, I did forget to check chips for hotness...blame that on a friend stopping by and talking me in to taking my motorcycle out (does not take much)

Yea if I have to send it off that's what I will do. I did buy this system non working as I wanted to tinker on another machine,no fun if all you have to do is plug them in! :)

Thanks for the help, I will update this thread once I/whoever tracks the problem down.
 
All voltage looks good on ARII and game PCB.

No chips are hot,warm but not hot,let the game run for about 30 or so minutes.

Also moved all rom chips around to see if I could change the display and nothing changed,so roms may be good.

Looked over the D8 and other areas,no broken traces or anything out of the norm.

With out a scope or probe anyway I can test the chips??

If not I will need to get this thing sent out and repaired....or go buy the tools :)
 
Small update...

Board is going on the "to learn on pile" I got another board headed my way.

I currently don't have the tools to T-shoot a chip issue,but plan on to get into board repair in the next 6 months or so once I save some cash up.

Just need a probe,scope and de-solder station and its on like...well Donkey Kong!
 
Moved them around? Each ROM must be in a certain socket, you can't just put them anywhere...

Yes I know this,was told by a fellow collector that you can use this trick to track which ROM might be causing the issue by getting the "Garbage" on the screen to change.

Still a big white screen on the play field so its not ROM's (as far as I can test right now)

And yes I put all the ROM's back in the right sockets after testing :)

Once I save up some coin and get a good de-solder station and testing tools (Probe,scope) I am going to tear into this...granted I am good enough to de-solder IC's with out a station and I do have an idea the chip that is causing the issue...I much rather wait till I get the right tools.
 
Back at it..

Guy that was selling the working board to me never got ahold of me, oh well.

So I am back at fixing this one.

Found a few cold solder joints and fixed them, also fixed the reboot issue and now it plays somewhat blind.

Still got a white playfield though, damn...

I am going to buy a probe but before that any one have a schematic on what areas I need to look at?

Thanks!
 
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I'm very curious as to what fixes this, i have a millipede i just picked up and it's doing the exact same thing yours is, but mine is not resetting at all.. i just have the score bar and the copyright bar at the bottom, and then a white screen in the middle, i can hear the game play fine, but just can't see anything.
 
Have not had the time to dig deep into this yet, got a few other boards I can start to test with though.

Resetting issue went away once I cleaned up all contacts. Tried a different CPU and that's not the issue.

Picking up a logic probe here soon and will go from there.

I was told it may be related to the D8 area of the board. Glad to know I am not the only one :)
 
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