Apple IIe scrambled display

Discussion in 'Apple Collectors' started by MaxHeap, Jun 14, 2014.

  1. MaxHeap, Jun 14, 2014
    Last edited: Jun 16, 2014

    MaxHeap macrumors member

    MaxHeap

    Joined:
    Mar 28, 2012
    Location:
    Missouri
    #1
    I was given this IIe and the only output I can get is the output attached. The computer also doesn't beep when turned on. I have removed all cards and it still displays the same. I haven't used a Apple II in years, so I could use some help on what to check next.
     

    Attached Files:

  2. MacTech68 macrumors 68000

    MacTech68

    Joined:
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    Location:
    Australia, Perth
    #2
    It's a little tough with a IIe, especially without a "donor" board to try swapping chips.

    However, the first thing I would try is reseating all the ICs. Press down in the middle of each IC to ensure they are well seated into the sockets.

    Check for any signs of corrosion, missing ICs etc.

    A pic of the motherboard might help to identify anything obvious.
     
  3. tdiaz macrumors 6502

    Joined:
    Feb 7, 2006
    #3
    Looks like it's not starting up on power on.

    It -might- try to do a self-test.. hold down both Apple keys on power-on, or four-finger reset. (Both Apple keys + (then) CTRL-Reset) and let go of CTRL-Reset first.

    Most likely won't do anything, but..

    By starting up, I mean executing the ROM, perhaps even loading it after power up. If the DRAMs are socketed, if you move the first four to the last four and last to first, you'll swap a potentially bad DRAM over to a spot that would allow it to startup, run self test and report the bad DRAM(s), if that is bad RAM, and it's occupying the higher areas, keeping the ROM from starting.
     
  4. MaxHeap thread starter macrumors member

    MaxHeap

    Joined:
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    Missouri
    #4
    Pushed on the chips to see if they were seated, they appeared ok. The screen output did seem to change a little with the self tests (see attached screen shots). I do also have a broken II+ to swap chips if that helps. Should I just check the PSU first?
     

    Attached Files:

  5. MacTech68 macrumors 68000

    MacTech68

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    #5
    Oh, that's, er, not so good. Mainly because so much of it is not socketed.

    The only thing I could see is a dull pin on the MMU (marked 344-0010).

    Yes, try swapping the power supply from the Apple II.

    This could be one that needs a logic probe to go much further, or a donor IIe to swap some of the custom ICs. Sadly, there isn't much that a II or II+ can swap with a IIe. :(
     
  6. MaxHeap thread starter macrumors member

    MaxHeap

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    #6
    The dull pin I just clean up with sand paper or some kind of abrasive? Should I remove pretty much anything socketed and reinstall or is there a step by step process I should take?

    The only thing with the II+ is that it doesnt work either. Should I hold off on the IIe and try to get the II+ working first? Which one is easier? I think the PSU might be at fault in the II+.
     
  7. tdiaz macrumors 6502

    Joined:
    Feb 7, 2006
    #7
    I'm almost convinced it's DRAM.

    What happens if you hold down the Open-Apple when you turn it on?

    Those Micron 4164s are soldered in, and are from the era of sketchy RAM.
     
  8. MacTech68 macrumors 68000

    MacTech68

    Joined:
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    Australia, Perth
    #8
    Yes, you can get some very fine sand paper and ensure each pin is clean and a little shiny. Take care removing the IC. Prise each end a little at a time. Eventually you can get the tool (long flat-blade screwdriver will do) into the middle of the IC. The trick is to lift the IC straight up, rather than lifting one end completely which can bend pins.

    As for the II+, try the IIe power supply on the II+ - They are the same pin-outs.

    Sadly, there isn't much that a II+ can provide that will help to diagnose the IIe motherboard.

    As for easy, the II+ uses mostly "off-the-shelf" ICs, which makes it easier, BUT many of those ICs are no longer stocked by smaller suppliers. The IIe is mostly custom ICs.

    Yes, I have to agree that RAM chips are one of the common faults in these machines. Sadly, being all soldered directly, you could end up needing to desolder them all, put sockets in, then test by swapping RAM ICs. - Not impossible, but you'll need some basic soldering skills to do it. Then again, you could do all that, and find it's NOT the RAM. :eek:
     
  9. MaxHeap thread starter macrumors member

    MaxHeap

    Joined:
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    Missouri
    #9
    I guess I'll first try to use the PSU from the IIe in the II+ as I think it's bad in the II+, then clean some chips! Thanks for all the help and I'll report any progress.
     
  10. MaxHeap thread starter macrumors member

    MaxHeap

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    #10
    Open Apple makes the screen change, so something is working. I looked a little closer at the II+ and it has rust on some chips, so it's a gonner.
     
  11. MaxHeap thread starter macrumors member

    MaxHeap

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    #11
    I found another website with same issue and they thought the CPU was the cause. I removed the CPU and got the same exact screen as before with the bars. Is this a good test and positive that the CPU is bad?
     
  12. MacTech68 macrumors 68000

    MacTech68

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    #12
    I'd be guessing if I said anything. Sincerely. :(
     
  13. tdiaz macrumors 6502

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    Feb 7, 2006
    #13
    More like the computer isn't starting up, and the CPU is not the culprit. But.. you can't tell without swapping that.
     

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