A&H GS3000 mpu problem

Discussion in 'Tech Talk - Electronic Repair Modifications DIY' started by Kevin Porter, Mar 16, 2017.

  1. Nanner Puddin

    Nanner Puddin Active Member

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    Apr 7, 2017
    Location:
    Knoxville, TN
    Update: Well I got my GS3000 back from my local Genius type tech guy. It turned out that there was a cold solder joint on the MPU that was causing the problem. He fixed that up and now it works fine. There was also a cold solder joint in one of the group meters, so this very well could be an issue endemic to the time period and/or factory where A&H produced it. Anyway, I do plan to get an extra MPU from A&H if I can, as a real failure on that could really screw me over in the future, as I plan on keeping this for a long time. Thanks to everyone for the help and good luck Kevin!!!!!

    Doug
     
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  2. Boswell

    Boswell Moderator Distinguished Member

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    Glad you got it fixed!
     
  3. Kevin Porter

    Kevin Porter Active Member

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    I just ordered the part from Jam Industries located here in Canada. They are the national distributor for A&H. Its a 3-4 week wait for them to get the part. It about 120 bucks all told.
    I have since bent and broke pins off the last eprom trying to get er going again. Not this time. LOL
    If i had more money i would have ordered a few of them. Jam part number is
    002-347JIT GS3000 MPU PCB
    Web page https://jamindustries.com/contact/
     
  4. Kevin Porter

    Kevin Porter Active Member

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    OK Bad news. I just got an email back from Jam industries and they said there is no more MPU's available so they have cancelled my order.. I am going to try and see if they can service the card locally. If not i will be shipping it to Boswell for repair.. Boswell, could you message me your shipping info??
     
  5. Nanner Puddin

    Nanner Puddin Active Member

    Joined:
    Apr 7, 2017
    Location:
    Knoxville, TN
    Well crap, mine just died again. One thing is wierd, every mute is on except the two Mutes for the AUX busses just above the master section. I have some jobs coming into the studio so I have to get this fixed quickly. I called Full compass here in the states and the said they can get a replacement but it will take 4-8 weeks on backorder. I went ahead and ordered even though I expect to be disappointed the same way as Kevin was. I also ordered an EPROM programmer and some blank EPROMS and sockets from EBAY. Hopefully I can get this fixed up as I really love this console!

    Doug
     
  6. Boswell

    Boswell Moderator Distinguished Member

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    Most likely to be bad contact between the EEPROM pins and the socket. If you have the official download of the EEPROM contents, it's worth programming one of your new ones and simply swapping it over to see if that makes any difference. If it works after doing that, use it for your immediate studio jobs and then consider swapping out the socket when you are under less time pressure.
     
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  7. Kevin Porter

    Kevin Porter Active Member

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    I managed to fix mine. I burned a eeprom and that didn`t work but hey i learned to burn eeproms!! Turned out the 5 volt regulator was blanking out in the power supply so i would check that out. Simple one dollar fix. Solder in a new regulator. Its been good ever since. I had broken legs off the original eeprom popping it in and out several times so the one i burned came in handy after all. There is no choice but to fix the MPU you have seeing as there is no supply for MPU`s anymore.
     
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  8. Kevin Porter

    Kevin Porter Active Member

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    The hardest part about the repair was decabling the console and staring at it forever once i had it standing up with the back off it. LOL I too love this console. Its been great and im quite happy i didn`t have to send it out anywhere to get it fixed. I actually bought all the parts in the power supply and was going to replace them all but once i changed out the regulator and it started working i just put it back together and will save the other caps and resistors for another day..Dont lose hope. Its a great console and can be brought back. If i could do it so can you. Bozwell has been a great inspiration in this endeavor and i have learned a lot as a result of his guidance on this and other repairs i have made to other gear i have.
     
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  9. Nanner Puddin

    Nanner Puddin Active Member

    Joined:
    Apr 7, 2017
    Location:
    Knoxville, TN
    Well how about that! I stood the console up and started checking the voltages on the MPU starting with the 15.6v input. I went backwards then from the 5V side and there was no voltage until after the 1 Diode. I poked around some more with the DMM and the all of the sudden it came on. In effect, the old circuit disturbance test. I pulled the board and reflowed the solder joints on the regulator and the diode. She is back in place and running as of now. I am now on a mission to aquire all of the spare parts I can that are on that board, and still available.

    On the plus side, I now have an EPROM programmer, a bunch of sockets and some blank EPROMS. I also have not heard back from Full Compass on whether they can get a spare board from A&H. I expect that to be a bust, but I will keep you guys posted.

    Thanks for all the help Kevin and Boswell!

    Doug
     
  10. Kevin Porter

    Kevin Porter Active Member

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    Awesome! I had a feeling you would ace it one way or the other. The parts on that MPU are pretty common and you should be able to get them just about anywhere that sells electronic stuff. All in all its a pretty bullet proof console aside from the MPU. I have never had any other issues with mine other than the only "digital" pcb in the console. I expect its a happy day in Knoxville
     
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