swapping MPU boards

[braddo]

Hi. Quick question.

Can I swap the MPU board from a Stern Seawitch into a Stern Galaxy? I'm not sure Seawitch is 7 digit displays and Galaxy is not, and I'm thinking the chips are different, but is there a way around it so I can troubleshoot the Galaxy?

With Galaxy I've gone over the board under the playfield, and gone over the board (don't know what that one is called it's the one with the large caps on it) in the backbox, and the MPU is next in line (I think).

I'm getting two chimes when I start her up and that's it. If I turn the machine off then on quickly I can sometimes get a game or so played on it. I'm thinking pins/connectors on the MPU board, but if it's something else I'll save my time. Cheers!

[Strangeways]

you can swap them over for testing. Check the J4 connector for corrosion or black pins. Use 320 Grit sandpaper to clean the pins and retest.

How many flashes do you get on the LED ?

[braddo]

I'm getting 2 quick flashes, then one more flash, but, it did fully boot up once, went into attract mode then reset back to the above.

Checked the pins, they don't look too corroded to me, and none look burnt. Been replaced before by the looks.

I'm waiting on some sandpaper to give them a clean this afternoon. Sorry this thread seems like it should go in the repairs section. Cheers Nino.

[Strangeways]

This means that the MPU is not "locked" - it is working, but up to a certain point.

What you should see is a brief "flicker" and then seven flashes.

First Flicker = CPU, PIA (U11) and ROM (U6) can be read = good sign

First "flash" = All ROMs are good

Second Flash = RAM (U7) is good

Third Flash = RAM (U8) - 5101 is good

Funny thing is - you mention it is going into "attract mode" - Sounds like U8 (5101) is not good - which is quite comon. This is also a chip that is prone to static. You can cover your bases by re inserting U7 + U8. Be VERY careful with U8 - try not to touch the legs or wear an anti static strap.

[braddo]

Nino, I cleaned the pins on the MPU, put the MPU in Seawitch hooked up the J4 and all flashes worked. So i pull the wires out of the J4 connector on the Galaxy, cleaned them and re-bent them to give them more tension, put it all back together and it's working . So my guess it's the connector, so i'll probably replace pins and connector.

I'm hoping the problem is solved, who knows it may reset at any time then i'll follow your next instructions, which I have also checked out at pinrepair. I'm going back to play it now hopefully it's still working .

Still got G.I. to look at, but BIG thanks Nino, how much beer do I owe you now??

[Strangeways]

Nino, I cleaned the pins on the MPU, put the MPU in Seawitch hooked up the J4 and all flashes worked. So i pull the wires out of the J4 connector on the Galaxy, cleaned them and re-bent them to give them more tension, put it all back together and it's working . So my guess it's the connector, so i'll probably replace pins and connector.

I'm hoping the problem is solved, who knows it may reset at any time then i'll follow your next instructions, which I have also checked out at pinrepair. I'm going back to play it now hopefully it's still working .

Still got G.I. to look at, but BIG thanks Nino, how much beer do I owe you now??

The fact it is fixed means that the connector and pins will need to be replaced in the future. "Resets" could be that connector, or C23 on the solenoid Driver board.

Enjoy the game !

[braddo]

Well I enjoyed it last night, played it for about an hour. What an underrated game!!!

Today it's going through the full 7 flashes then resetting before it starts, so looks like new connectors and pins for J4. C23 has been replaced so I at least I think the problem has been tracked down.

[braddo]

Can i swap solenoid driver boards between Galaxy and Seawitch, and then actually play the Galaxy with Seawitch SDB??

I want to check C26, I can't think of what else the problem could be. The game starts up every time, but resets during first/second game. Voltage readings on the MPU (J4 and test points) are fine.

EDIT - I swapped the boards it not C26. This is nuts. I going to go over everything again and get readings again before anything else. I'll get there.

[braddo]

OK I need some help i'm stumped.

All test point voltage readings are fine, but i'm still getting resets. Any idea on where to go from here? MPU has new pins connectors, SDB has new pins connectors, PSB under playfield has new pins connectors. It boots up, goes into attract mode, sometimes I can play it, but it still resets. Even pushing the credit button to put some credits up can cause it to reset. Where do i go??

[Strangeways]

Is there much corrosion NEAR the battery - is the original battery still installed ?

Sounds to me like corrosion in the reset section of the MPU.

[Ballywannabe]

Try and narrow the problem down - put the Seawitch MPU in and see how stable the machine is (put it in self test).  If it goes fine you have at least narrowed it down to the MPU.  If it still resets regularly I would still suspect connectors.

cheers
Ian

[Rod71]

Have you checked the slam switch on the door?.  bit of a long shot, but certainly possible.

[braddo]

Cheers Guys.

Nino - A battery pack has been installed and as far as I can tell there is no corrosion on the board.

Rod - There is no door switch I guess it has been removed.

Ian - I will try the Seawitch MPU again tomorrow

One thing i should mention, when I go into test mode, the right sling and knocker go crazy. Turn it off then on, ran the test again and it went OK. Tried the test again 10 min ago and the sling and knocker went crazy again then the machine reset. I'll change MPU tomorrow and go from there.
I also should mention the machine has gone back to not wanting to boot up, sometimes it only makes it to two flashes . I'll keep poking around.

[Strangeways]

Reseat the two PIAs - U10 & U11.

[Rod71]

Reseat the two PIAs - U10 & U11.

Kind of explains the wacky solenoids sometimes in test mode doesn't it.

I'd be doing the same with the 5101 while i'm there.