(Topic ID: 253525)

Alltek MPU only 3 flashes


By Madmax541

8 months ago



Topic Stats

  • 22 posts
  • 7 Pinsiders participating
  • Latest reply 8 months ago by treborlicec
  • Topic is favorited by 1 Pinsider

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    #1 8 months ago

    Skateball
    Was working fine, went to turn it on and only get 3 flashes. No displays, but have glow indicating power present.
    History: alltek MPU, LDB, SDB, all pins have been repinned w exception of display connectors.
    All fuses are good
    Voltages check at MPU & SDB, and display.

    3 flashes points to RAM or PIA issue.
    Switched out MPU with another MPU same issue.

    Ideas?
    Thanks

    #2 8 months ago
    Quoted from Madmax541:

    3 flashes points to RAM or PIA issue.
    Switched out MPU with another MPU same issue.

    So you swapped MPUs, did you swap the RAM and PIA to the other MPU and it returned only 3 flashes?
    If yes then your problem followed the RAM and PIA chips, thus one is bad.
    If NO, then your problem is NOT the RAM nor PIA?

    #3 8 months ago

    When swapping MPU no chips where changed.

    Repeat of 3 flashes, tells me issue isn’t on MPU.

    What should be my next move in trouble shooting this?

    #4 8 months ago

    Since the problem follows the boards, perhaps a connection issue. These older games are often candidates for repinning.
    Very carefully wiggle your connectors to see if you find one that may be bad.
    Do you have a good solid ground connection?

    #5 8 months ago

    Try unplugging the sound board and see if that makes a difference.

    #6 8 months ago

    All connectors have been repinned.

    I will try disconnecting sound card tonight

    #7 8 months ago

    Are you swapping with another Alltek MPU with the DIP switches set for Skateball?

    #8 8 months ago

    No 4th flash means the CPU cannot control all the PIA ports. If you switched MPUs and the problem remains the likely issue is something is shorted that is connected to the PIA.

    Unplug the displays, sound board, lamp driver J4, solenoid driver J4. Power on and you should get all 7 flashes. Start plugging devices back in one at a time until you find what is making the PIA test fail.

    #9 8 months ago
    Quoted from westofrome:

    Are you swapping with another Alltek MPU with the DIP switches set for Skateball?

    Yes

    Quoted from barakandl:

    No 4th flash means the CPU cannot control all the PIA ports. If you switched MPUs and the problem remains the likely issue is something is shorted that is connected to the PIA.
    Unplug the displays, sound board, lamp driver J4, solenoid driver J4. Power on and you should get all 7 flashes. Start plugging devices back in one at a time until you find what is making the PIA test fail.

    Will do, appreciate the direction

    #10 8 months ago

    Unplugged
    all displays
    LDB J4
    SDB J4
    Sound board

    Still only get 3 flashes

    Plug in another alltek MPU led stays on.

    #11 8 months ago

    Continuing on: with all of the connectors removed as before, plus now remove all connectors on the MPU except for J4. Now what happens?

    #12 8 months ago

    With only J4 connected on MPU I get only 3 flashes

    Guessing this means problem is isolated.

    Which chip (s) are likely problems?

    #13 8 months ago
    Quoted from Madmax541:

    With only J4 connected on MPU I get only 3 flashes
    Guessing this means problem is isolated.
    Which chip (s) are likely problems?

    Seems really unlikely two MPUs have the same issue. With only MPU J4 connected and driver J4 off you have isoalted the MPU away from everything but the power input. Can/did you confirm both MPUs work in another game?

    Is it possible you are counting the flashes wrong and are actually missing the 7th and last flash? There is a delay between two flashes that lasts longer than the rest of the flashes and people get confused and start counting at 1 after the delay flash. No 7th flash is caused by the zero crossing detector not working. Usually this means the 43v solenoid fuse on the rectifier board is blown. Check that, I think its 5a fast fuse.

    #14 8 months ago

    Tried my 2 alltek boards that where failing in Skateball into Fathom both boards failed. Put original mpu into Fathom it worked fine.

    So both alltek boards are bad 3 flashes, could a switch be stuck in skateball causing the alltek mpu failures.

    Very reluctant to put another working mpu into skateball.

    Thoughts?

    #15 8 months ago
    Quoted from Madmax541:

    Tried my 2 alltek boards that where failing in Skateball into Fathom both boards failed. Put original mpu into Fathom it worked fine.
    So both alltek boards are bad 3 flashes, could a switch be stuck in skateball causing the alltek mpu failures.
    Very reluctant to put another working mpu into skateball.
    Thoughts?

    If you put the questionable board(s) in a different known good game and it you still get only three flashes only and the other MPU works than it likely is something wrong on the non booting board. Seems strange two boards would have the exact issue. I guess also in realm of possibilities the skateball game has something shorted that is blowing out the U10 PIA chip (no 4th flash).

    If you are feeling dangerous you can try moving a new known good 6821 chip into the non working board at U10 as no 4th flash is complaining about that chip. Could borrow it from a different MPU. Might want to check with alltek or the distributor about warranty stuff first.

    #16 8 months ago

    I have some 6821 on hand. Will give that a try. The 6821 on alltek is U6 not U10 just making sure we are talking about the right chip.

    #17 8 months ago

    Have you tried resetting the Alltek MPUs?

    #18 8 months ago

    Replaced 6821 connect one connector at a time no issues.

    Once booting is complete it activates coils like a ball search one time. Tried another SDB same thing.
    Put it in solenoid test mode passed.

    Reboot 7 flashes no displays.

    Will check voltages later this morning. Thinking something is shorting on PF

    #19 8 months ago
    Quoted from westofrome:

    Have you tried resetting the Alltek MPUs?

    Do you mean resetting push button on bottom of MPU?

    #20 8 months ago
    Quoted from Madmax541:

    Do you mean resetting push button on bottom of MPU?

    I mean running the memory clear function

    6983BE4F-1C9B-40D1-822D-8C66DFB3DDE4 (resized).jpeg
    #21 8 months ago

    What chip is at U10? If it is a WDC W65C21P if so the 6821 is probably drop in compatible.

    If the MPU now boots with the new U10 in then its not a memory clear issue.

    U10 controls part of the displays, switches, and lamps. Coil voltage to a switch or high voltage from a display to PIA port would be a way to damage the U10 chip.

    Quoted from Madmax541:

    Replaced 6821 connect one connector at a time no issues.
    Once booting is complete it activates coils like a ball search one time. Tried another SDB same thing.

    That sounds like it is in stern's burn in test. When all option 1 to 32 dip switches are set to off and mpu game selection software is set to stern MPU200 game or later MPU100 games it will boot into burn in mode where all coils pulse one at a time.

    #22 8 months ago

    The good thing is Alltek has a lifetime warranty. My MPU failed in my Strikes and Spares. I did a little troubleshooting as requested by Alltek and they ended up sending me a new one after I returned the faulty unit. Hopefully the memory clear helps.

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