Apple ][+ repair

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Last seen: 13 years 3 months ago
Joined: May 17 2006 - 20:31
Posts: 2
Apple ][+ repair

Hello all, I have an Apple ][+ computer here that I'd like to repair, yet I have no idea what's going on with it. when I first got it, I tried the DOS disk but quickly found out that either the controller or the drive itself wasn't working properly. I removed the components and tried again. This time, monitor came up and everything was all good and I had my fun tinkering with the basic language.

The next day, I went back and turned it on, but i was no longer greeted with "APPLE ][", but with this;

I tried all sorts of things to get it to work, removed and cleaned all the pins on the chips, running with no perhipherals, but nothing worked.

As far as I can tell, it must be a ROM error, but I don't know for sure.

Could also have been temperature fluctuations damaging a chip, thing probably hasn't been kept in a climate controlled environment or even seen power for many years.

I don't know, but really would like to repair it.

What do you guys think is broken and what should be my next course of action?

Last seen: 3 years 9 months ago
Joined: Apr 10 2006 - 20:01
Posts: 1013
Re: Apple ][+ repair

cirvin_fox wrote:
The next day, I went back and turned it on, but i was no longer greeted with "APPLE ][", but with this;

There was a newsgroup discussion a little while ago on comp.sys.apple2 where lots of folks chimed in on their ideas of how to go about diagnosing a sick Apple ][. Here's a link to the thread on Google:

Last seen: 6 years 6 months ago
Joined: Dec 20 2003 - 10:38
Posts: 249
Yes, follow that thred becaus

Yes, follow that thred because it does cover quite a few ways to test your II.

When trouble shooting a II the best way is with no cards in any slots. If you have a 16K RAM card in slot 0, remove it along with the cable that plugs into the chip socket. It will work even without anything in that socket.

Make sure your chips are seated correctly. Start with the 6502 1st as this looks like a possible problem area. Reseating chips is the best shot for an easy fix. Many times the contacts get buildup on them from moisture and other storage issues. Reseating the IC's scrapes the contact pins and creates better connections.

Once you have the II up, you can then start adding your cards back one at a time. Be sure to turn the II off before adding cards back into the computer. After adding each card, test the system. This helps determine if any of the cards are causing the problem.

Hope this helps you get started.


Last seen: 13 years 3 months ago
Joined: May 17 2006 - 20:31
Posts: 2
Sorry for the delay, lost pas

Sorry for the delay, lost password, anyway...

I tested the reset circuit the other day, watched the line on my 'scope and it seemed to not be working, so I removed the transistor mentioned in the article, but still feeding it a manual reset did nothing.

I probed the other lines and AFAIK, it's getting a clock signal but I'll go more in depth with it later.

Checked for broken traces and found none.

An odd thing, if I press reset repeatedly, sometimes the speaker will make an odd sound, sometimes a buzzing, sometimes clicking, and once I got a rather high piched tone, if that means anything.

Thanks for the help so far guys, it's much appreciated. Smile

Oh, I have gone and reset most every one of the chips on the board, that was one of the first things I tried. I'd do it again, but I know I'd go and damage a couple chips pins. Already lost a couple RAM chips to my heavy handed methods of extraction.

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