NEC PowerMate 1 Plus (APC-H2010F) 80286

Discussion in 'Retro & Arcade Worklogs' started by sean0118, May 18, 2019.

  1. callan

    callan Member

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    That's awesome that the disks still work, after all these years!!! Makes me happy they've been put to good use.
    As I mentioned in PM, as it's NEC-DOS 3.3 you should be able to partition and format hard disks larger than 32Meg - it fakes sector sizes to be bigger than 512 bytes to the partition table :)

    That Epson monitor sure has seen some action :p

    Callan
     
  2. Phido

    Phido Member

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    I have a great affinity for 286's.

    The first computer I bought as a kid was a Wang 286. Enormous thing. Probably more than twice the deskspace of this NEC.
    Many great memories. Was the only computer I actually sold. Wish so badly I had kept it.
     
  3. Flamin Joe

    Flamin Joe Member

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    I have a soft spot for 286's but for a different reason. For many years we had an XT clone so when games started requiring a faster CPU it was not uncommon for the game not load to be greeted with the "requires a 286 or higher" error at the DOS prompt. In fact I think many games boxes around that era would also say the same or have "286 minimum" written on the system specs. So I guess in my young mind the 286 became the key to unlocking so many great games became the PC I wish I had. :)
     
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    sean0118

    sean0118 Member

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    Yeah, it's quite unusual, I'm looking forward to getting some games running on it.

    It's an Epson Flexscan 8060S-FA from 1988, I've never been able to find any info on it. It's some sort of multiscan, can accept different inputs. Can also switch the display between between amber, colour and black & white.

    The tube in it is actually an NEC M34JUQ23xx, but I can't find any information on that either.

    I got this from hard rubbish as well, at a similar time to the NEC 286 but not from the same place. It was really dirty, just got around to cleaning it now. :lol:


    Thanks for sending them Callan, saved me heaps of time.

    Yeah the Epson was really dirty inside and out. Was pretty dim as well, but seems much brighter now, I guess it hadn't been used for 20+ years. ;)
     

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    sean0118

    sean0118 Member

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    Well, bad news I'm afraid. :(

    I was getting both the 3.5" and 5.25" drives to work by using a controller card, rather than the motherboard floppy connector. But I couldn't run any programs, all games etc would fail with 'error in EXE file'. Both of the drives and the controller were working fine in my 486, so I was starting to suspect there was some incompatibility with the NEC DOS 3.3 or maybe the MDA graphics. Although, some of these were text adventure games so should have run using MDA.


    But while I was exploring the cause of that error, strange things started happening. First I started getting random characters sometimes when pressing the keyboard. Then it stopped detecting drives, resetting would fix it, but then it stopped turning on sometimes, or it'd shutdown after a few seconds.

    Now it doesn't POST at all, the power LED comes on and the keyboard flashes but that's all. I've tried only having the MDA card and monitor attached, but it doesn't POST at all (screen stays blank).

    I still need to test the MDA card in another PC, but I really suspect the keyboard controller IC. There's a thread on vcfed with a similar issue: http://www.vcfed.org/forum/showthread.php?45843-Motherboard-repair-required-NEC-powermate-1

    The original controller is an Intel D8742, it's an EEPROM so needs to be programmed. In the photos it's the one with the silver sticker with 'YAN25D05'. The good news is I can get the ROM version, the 8742AH for quite cheap on ebay. So I might just get one to see if it fixes it. ;)
     
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    sean0118

    sean0118 Member

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    I realised I had the speaker unplugged, with it plugged in I'm getting all sorts of error beep codes.

    The most common one I'm getting is 1-2-3, but I've also heard 3-1-1 sometimes. I found some info for Phoenix Bios codes, I'm not sure if it applies to my bios version or not. But it looks like both of these codes correspond to DMA IC failure:

    http://www.bioscentral.com/beepcodes/phoenixbeep.htm

    Know I just need to work out what the DMA IC is. :lol:

    edit: so looks like the DMA controller is integrated into the N82231-2 IC
     
    Last edited: Oct 6, 2019
  7. callan

    callan Member

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    The BIOS's in NEC machines of that vintage were phoenix-based.

    Callan
     
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    sean0118

    sean0118 Member

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    Thanks Callan, I think I might be getting somewhere. I took the N82231-2 out and cleaned it and it's socket. There are a few contacts on the socket which look the wrong colour, not bad corrosion, but not quite right. I also found that the socket has a small fracture in one corner so it might not be applying enough pressure on the IC pins.

    After reinserting it I'm now mostly getting a 1-2-2 beep code, which is also a DMA failure error.

    The socket is a 84 pin PLCC, there's lots around, even good quality ones are quite cheap. So I'll just replace it and see what happens.
     
  9. BiggusDickus

    BiggusDickus Member

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    I was lucky enough to have one of these all through my early teens. Had a beautiful NEC multi-sync monitor to go with it.

    Played endless hours of games on this machine. Seeing these pics really brings back the memories.
     

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