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Thread: Apple II Clone Keeps Repeating Keys - Help?

  1. #11

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    Quote Originally Posted by David_M View Post
    Powering on with a screen full of question marks is a completely different scenario than a screen filling with question marks after pressing a key.
    You need to be really clear on the fault description for advice to be good enough to be of any help.

    Did the fault change after you reseated the chips or did it always have a screen full of question marks at power on?
    Does it power on normally without question marks with the keyboard unplugged?
    Does it power on normally without question marks with the keyboard plugged in and olny starts generating question marks after you press the "?/" key?

    Also when I suggested the reflow, the problem is more likely on the scanlines and the associated pull up resistors not the individual keys. Posting a photo of the chips on the keyboard will allow me to point you at the chips most likely to be the problem.
    Due to the inaccurate description of the fault you probably should expand your fault search and check the mainboard IC's at B5, B6, A12 and C11
    The screen was filling with question marks after pressing a key, I re-seated some chips and the problem changed into a pre-filled screen on boot.

    Using some bodge wires I managed to get it back to regular boot + screen filling with question marks upon pressing a key, so to answer your questions:

    1. The very first time I powered it on, the screen was full of question marks with some flashing squares scattered here and there. I re-seated some chips and it booted normally, which is when I encountered the problem where trying to type a question mark would progressively fill the screen with them.

    2. Sometimes on boot the question marks begin to scroll immediately and can be stopped by hitting Return. Powering it on with the keyboard unplugged doesn't change this, it seems completely random. Other times it boots just fine until you try to make a question mark. Occasionally the "<", "7", and ";" keys trigger the exact same problem as the question mark one, but with those characters instead. This isn't all the time though, the only constant problem occurs when trying to make a question mark.

    3. See above.

    After fiddling with it for a few days it's clearly above my current skill level and I'd rather have money for other projects, so it'll be going on eBay on Sunday. Thanks to everyone for your help! Hoping the next owner figures it out.

  2. #12

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    Actually ignore that last part of my reply, I can't edit it because it hasn't been posted yet (pending moderation due to my account being fairly new).

    I think I'll persevere with this and try to figure it out. The clone is pretty cool and I'd like to hang onto it and get it running properly since I'm passing on my Apple IIc soon, and I just got a good deal on a Disk II (still need an interface card though, any Australians got one to spare?) - I'll check those ICs and report back. I'll also take some proper photos of the board.

    I was looking at some photos of real Apple II boards online and the positioning of some of my chips appear to be different, but it should be easy enough to figure out which are which.

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