(Topic ID: 188349)

I think i blow my rottendog mpu327


By riverinapinball

3 years ago



Topic Stats

  • 24 posts
  • 12 Pinsiders participating
  • Latest reply 11 months ago by creepykenny
  • Topic is favorited by 3 Pinsiders

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    #1 3 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 3 years ago

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

    #3 3 years ago

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

    #4 3 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 3 years ago

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

    4 months later
    #6 2 years 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 2 years 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 2 years 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 2 years 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 2 years 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 2 years 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 2 years 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 1 year ago

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

    #14 1 year 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 1 year 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?

    8 months later
    #16 1 year ago

    also having an issue with a 327-1 and the current schematics don't match & rom/code (327-4) does not work on the early series boards ... ask me how i know

    board will pass the leons self test running the -4 code, but thats about it

    2 weeks later
    #17 11 months ago

    a follow up here, was finally able to repair this non-working 327-1 mpu, i believe the current schematics may be drawn with a couple errors related to the dips - maybe, and better yet, the latest 327-4 code does indeed work with the older boards so thats a positive

    just about every i/c that has an "hct" on it was blown/bad

    and was able to find the 74HCT9114 at K's arcade (yes, mine was blown and part of the problem)

    so, replaced the crystal, ram, rom, and about 8 gates, all of the 6821 & mpu were OK, don't know what happened to this board but whatever it was, it wasn't good

    #18 11 months ago

    Ive had problems with those HCT's before...crap

    #19 11 months ago

    Over the years on this site I have noticed that Rottendog boards appear to have a lot of inherent problems which makes me wonder if they should be avoided. I've seen many threads where they just don't work or are very shaky at best right from the start.

    #20 11 months ago
    Quoted from creepykenny:

    a follow up here, was finally able to repair this non-working 327-1 mpu, i believe the current schematics may be drawn with a couple errors related to the dips - maybe, and better yet, the latest 327-4 code does indeed work with the older boards so thats a positive
    just about every i/c that has an "hct" on it was blown/bad
    and was able to find the 74HCT9114 at K's arcade (yes, mine was blown and part of the problem)
    so, replaced the crystal, ram, rom, and about 8 gates, all of the 6821 & mpu were OK, don't know what happened to this board but whatever it was, it wasn't good

    A bunch of dead HCT chips is a good sign the board took over voltage on 5v supply. I have had to fix a few replacement bally mpus where someone accidently put 12v down the 5v rail and it kills every single HCT chip. Other logic flavors seem more likely to survive.

    #21 11 months ago
    Quoted from RWH:

    Over the years on this site I have noticed that Rottendog boards appear to have a lot of inherent problems which makes me wonder if they should be avoided. I've seen many threads where they just don't work or are very shaky at best right from the start.</blockquot

    Yes there have been some complaints, but how many people think, when there game wont boot: just get a replacement board without finding out what happened to the last board. If you don't fix what's really wrong you will just cause new problems on your replacement board! This isn't Rottendogs fault,
    but they are usually more that happy to repair it at no additional cost.
    I've used several rottendog products, and the only ones that have ever failed, were a result of unknown problems elsewhere.
    I wouldn't discourage one of the few people (company) who is willing to make new replacement boards. I'd stand behind them.

    #22 11 months ago

    Oh no, I'm not saying their product is not worth buying, merely stating that what he was describing I've heard a few times before hand. I do appreciate any company that produces products to keep our games humming.

    #23 11 months ago

    I have a 327 in a Flash, first time I installed it, (all voltages were correct) blow most of the IC chips, due to bad display board that feed HV
    back to the mpu.
    They repaired it no charge, about 2 weeks latter I ended up having a problem with the switch columns, after blowing out about 15, 74HCT9114 chips
    I found that one of the pop bumpers was not mounted correctly, (had to flip coil over). It would randomly short out against a drop target switch that was to close to the coil lug.

    live and learn, but not RD fault, mine.

    #24 11 months ago

    well, it actually almost a pleasure to work on a board that doesn't have acid damage or an interconnect

    so, I got to a point where the board passed the leons self test but when in game mode the two leds just locked on, that's is where I began to suspect the program was the problem - I spoke to Jim at RD and he stated it should be fine with their -BD code.

    problem turned out to be the 9114, replaced it and then got the normal short single flash from the two leds indicating the game code was running

    I then discovered that the 74hct154 multiplexer was also blown - nothing on displays is a good clue of its demise, and logic probe agreed, replaced it with a 74154 and all is good

    the feedback I have read concerning the HCT series indicates it is quite fragile

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