(Topic ID: 188349)

I think i blow my rottendog mpu327


By riverinapinball

2 years ago



Topic Stats

  • 15 posts
  • 7 Pinsiders participating
  • Latest reply 6 months ago by SYS6
  • Topic is favorited by 2 Pinsiders

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    #1 2 years ago

    As title suggests.
    I was changing out my flashers on my Firepower and now the Rottendog Mpu327 will not boot and both Leds on the mpu are lit solid.
    Have i blown a chip?

    #2 2 years ago

    If you shorted a lamp socket to a switch then yes. You need to replace the switch IC.

    #3 2 years ago

    I can run the Leons Test on the mpu and it appears to work.
    Could it be the 6264 ram?

    #4 2 years ago
    Quoted from snowvictim:

    If you shorted a lamp socket to a switch then yes. You need to replace the switch IC.

    So one of the PIA ics.

    3 weeks later
    #5 2 years ago

    Replaced one of the PIA and shes up and running again!

    4 months later
    #6 1 year ago

    I was adjusting the flipper eos now half of the switch matrix is out. Does any know which ic or pia control the switch matrix on rottendog mpu327-1

    #7 1 year ago

    I switched out the pia one at a time, and i now have the switch matrix all working except one column.

    Maybe a wire off or bad diode.. unsure. Or maybe another ic. The rest of the ic s are not socketed..damn

    I may need to source a schematic.
    Can anyone piont me in the right direction.

    #8 1 year ago
    Quoted from riverinapinball:

    I may need to source a schematic.
    Can anyone piont me in the right direction.

    There's a downloadable MPU327 schematic on this page:

    http://www.arcadeshop.com/i/692/williams-system-3-to-7-mpu-driver-board.htm

    #9 1 year ago

    Schematic is diffferent to my board. Mine is a mpu327-1

    Fault is tested as on the board.
    I will go over it when i have some time.

    #10 1 year ago
    Quoted from riverinapinball:

    Replaced one of the PIA and shes up and running again!

    I have a rottendog MPU 327 that died after only a month of use, no boot and no displays, which sounds very similar to your story. It passes the self tests, I sent it back to Jim a couple times where it passed the same self tests and was sent back to me, but it never worked again in a game (meanwhile the original MPU and driver did, so the fault was definitely on the MPU 327).

    I recently got in touch with them hoping for a troubleshooting guide so I could use the board in another machine, but they don't seem to be able to do anything besides the self tests. It sounds like mine might may the same issue as yours, how did you figure out which PIA was faulty and needed replacement?

    #11 1 year ago

    Ju

    Quoted from EvanDickson:I have a rottendog MPU 327 that died after only a month of use, no boot and no displays, which sounds very similar to your story. It passes the self tests, I sent it back to Jim a couple times where it passed the same self tests and was sent back to me, but it never worked again in a game (meanwhile the original MPU and driver did, so the fault was definitely on the MPU 327).
    I recently got in touch with them hoping for a troubleshooting guide so I could use the board in another machine, but they don't seem to be able to do anything besides the self tests. It sounds like mine might may the same issue as yours, how did you figure out which PIA was faulty and needed replacement?

    Mine is booting up.

    The pia's are all 6821 . i just swapped them out (with some spare 6281 i bought of ebay) one at a time until some switches started to test ok again. But i still have one switch column out.
    It seems to be one of the other chips 74??? But which one? I am NO electronics tech. But i am building up some trouble shooting skills.

    If your isnt booting suspect the one or more of the pias. If solenoid voltage get shorted to lamp or switch matrix. These blow!

    1 week later
    #12 1 year ago

    I emailed Rottendog. They have been very helpful.

    The suggested the following

    "
    First thing to do, is swap the chips in IC27 and IC36. They are the same chips. If you do the swap, and it fixes, then that is the culprit. If it doesn't, the next step would be replacing the 74HCT 9114 located in U17. We specifically made that chip socketed, because the issues that would burn up those chip were semi-common. Our distributor, ksarcade.net, keep these on hand and will be more than happy to provide them. If it were me, I would get a couple as a "just in case". Normally if the issue isn't resolved away from the board, that will chip will blow again."

    I had already replace ic 27 and ic 36. So my fault must be in u17 the 74hct9114 . Mine isn't socketed , but i will remove it and replace it with a socket.

    So i contacted ksarcade and I was told that the 74hct9114 is obsolete and they are unable to source any and are out of stock.

    I did some googling and came across some 74hc9114n which i have been told is an ok replacement.
    They are coming from China so i will try one when it arrives.

    11 months later
    #13 8 months ago

    Old thread, but did you fix this? I am having a very similar issue :/.

    #14 8 months ago

    This one has my curiosity up -- why was a 74HCT9114 used?
    Can't find schematics. Anybody know what is connected to pins 1 and 19 on the board?

    1 month later
    #15 6 months ago

    Since 74HCT9114 has nine gates I suppose you could cludge a fix to use the spare gate if the mounting bracket issue shorts and destroys one gate?

    Also since it looks like pull up resistors are used on the column drive outputs I think you may get away with 74HC9114 which might be easier to get hold of?

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