Apple II Plus Mayhem

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Joined: Jan 8 2010
Posts: 4

Okay,
So recently I purchased an Apple II Plus, it tested out okay without it's floppy. I could turn it on, get to a command prompt, type in some commands, write some basic, and run it. All was well. I finally decided to hook up the drive, I have an Apple Disk II 5 1/4 floppy, the one with the black face and bezel. I grabbed the first available bootable disk I had, an dold Applied Engineering AW 2 Expander Disk. I went to boot the machine, got the beep, the driver chugged and whirled, and in a few seconds I had a menu. This is where things start to go awry.

I notice that there's quite a bit of flickering in the menu list on the screen. I go to choose a selection and I get nothing. I hit ctrl-reset, and pull the disk. I get to a command prompt after reboot, type in a letter (any letter) and I get 6-7 lines of that letter that appear instantly, and then the last row the letter repeats out like I'm holding down a repeat key. Then it "returns" automatically, I get a backslash character, a carriage return, and then a new line that starts with an asterix below the old one (plus repeated letters), and it does the same thing. It's caught in an endless loop. If I hit another letter it simply starts again with that letter from that point, and then continues into the new line. So I get a paragraph full of the letter "H", then a rapidly repeating "H", until it reaches it's "end" then it starts over. Also in a short video I made I noticed that at the top immediately after reboot, I can see what looks like something from the assembler, the row across the top has these entries.

"00A9- A=FD X=00 Y=FF F=B5 B=F2"

But other times after powering off and back on, I get a standard prompt instead of the asterix, I still get the backslash though and return.

I've uploaded a movie HERE! to check out.

Here's what I've done. I removed everything. All expansion cards, keyboard. I've pulled the encoder ROM on the MLB. At least I think it's the keyboard encoder ROM. It actually has a Videx sticker on it. It has imprinted on it "LOWER CASE (c) 1981 VIDEX". I assumed it was the encoder, I tried pulling and reseating it, but no love. So at present I have an Apple II Plus, sitting here with no case, no Int card, no drive card, speaker unplugged with only power and video plugged in. That seems to be caught in some kind of text repeating loop.

Weird huh?
Any ideas would be very much appreciated
Thanks
Joe

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Offline
Joined: Feb 24 2009
Posts: 10
Apple II Plus Mayhem

Hi,

This is easy, your W key is stuck down or faulty, and is sending lots of W's to the computer. That's why the menu was flickering, as it was the program getting lots key presses that most likely were the wrong option. Check the key on the keyboard, or unplug or replace the keyboard and it should stop.

That forward slash char is the computer not allowing more than 256 char's on a single command line input. I think it was 256.

Grant

Offline
Joined: Dec 13 2005
Posts: 264
Keyboard troubles

Hi,
If the W key is stuck then this might work.

I posted it in the Vintage Computers as well. I use a few different screen name. I have done this with a few different key boards. Why and how I came up with this approach. Was I had one key that did not work all the time. But that how found it works.

http://www.vintage-computer.com/vcforum/showthread.php?t=9517

Also look here under Keyboard troubles

Take Care,
Twilight_Rodent/Geo3

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Joined: Jan 8 2010
Posts: 4
Issue continues

Thanks for the replies so far.
I thought about the stuck key thing myself. I've completely removed the keyboard and all expansion cards ( I mention that near the end of my original and probably too long post). Basically at this point I have a bare Logicboard connected to a power supply and a video monitor.

Does anyone know how the repeat key works with the logicboard? I wonder of it's possible that it can toggle on the repeat function on, then break, but the logicboard remains "locked" in that mode, even between power cycles?

It's weird stuff
thanks
Joe

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Joined: Jan 8 2010
Posts: 4
One more thing

It's not just W it's any non modifier key I hit. Including esc, return, everthing except shift, repeat, and reset

gsmcten's picture
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Joined: Oct 4 2005
Posts: 2609
This may be stupid, but.....

1. Have you tried diconnecting the keyboard and starting the computer to ensure its a keyboard problem?
2. Have you taken out and reseated all of the chips on the motherboard and then started it?
3. I believe that the "Videx Lower Case Chip" is a third pary chip and if you could try replacing it with the normal chip to see if it (the Videx Chip) is the problem.

It can't hurt. Smile

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Steven (gsmcten)

"Apple ][.....It's ALIVE!!!!!"

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Joined: Jan 8 2010
Posts: 4
Yep tried that

Yeah I tried the disconnected keyboard. If I had a second II+ I would have definitely swapped that encoder chip. Guess I'll be shopping for a second II+. I just got Jim Sather's book on Apple II maintenance, maybe I'll find something there.
Thanks
Joe

woogie's picture
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Joined: Dec 20 2003
Posts: 267
Another approach

I know it's "out there" but not unheard of...did you check
all of your power supply connections? Might be a dirty connection
causing interuupted pulses to the whole motherboard. I kind of
think that this COULD be the case as you seem to have exhausted
all of the other ideas. Strager things have happened....wouldn't
hurt to try.

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