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Thread: Expert 4044 motherboard doesn't seem to be POSTing?

  1. #1

    Default Expert 4044 motherboard doesn't seem to be POSTing?

    I got an unconfigured Expert 4044 with a Cyrix DX2 80MHz CPU, and I'm trying to get it running. It doesn't have a PC speaker yet, as it didn't come with one, and I don't have any spares. I've set everything with two exceptions according to this: https://arvutimuuseum.ee/th99/m/C-D/35866.htm
    I haven't changed the cache setting from when I got it, as they looked correct, and currently I have the CPU set for what the documentation labeled "6V" which I'm hoping is a typo for 5 Volts, because there's no 5 volt option listed. The graphics card works in another system, and the RAM is 2 NOS (to my knowledge) 4MB 72-pin SIMMs. There is no barrel battery or corrosion. If I set it for a DX2 66 and put one in, it gets hot, but still doesn't show life otherwise. The monitor does not recognize any output from the card. If someone could help me troubleshoot it, I'd be grateful! Thanks!
    Looking for: Tandy TRS-80 Model 100/101/102, Macintosh LC III/Performa 450, working Zenith Z-171 floppy drives

  2. #2

    Default

    If you haven't already, force CMOS clear. You can clock a 40 MHz part at 33 MHz and timing will loosen up some.

    One 72-pin SIMM is enough for POST to succeed. IIRC you need FPM not EDO RAM.

    I recommend that you try one of those ISA/PCI debug cards - I have one from ebay that works well. This will help you figure out if the CPU is failing to start, or if you are failing partway through the POST.

  3. #3
    Join Date
    Jul 2009
    Location
    Central Florida
    Posts
    3,821

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    I have had a couple of boards exhibit the same behavior. CPU gets warm and nothing else. Wound up having to use some electronic spray cleaner on the simm slots and then it booted. Also did same in the ISA slots. Could just be dirty contacts from sitting around a while. Hopefully that simple. Got the cleaner from Ace Hardware. Its in a red can
    *FrankG*

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