Atari 130XE, Bad RAM, Won’t pass memory test. Plus failed keyboard!

Somehow, somewhere I achieved a 2nd Atari 130XE home computer. This is the more advanced version of the first computer that I started on – the Atari 800XL. I really liked the Atari 800XL, it was a sleek computer and looked better than the Commodore 64.

At some point I had a 65XE but can’t seem to find it, but was confused when I found the 130XE that didn’t work. I think maybe my buddy Cyberflux gave it to me — I’m not really sure. Anyways, we can’t have broken stuff taking up space so the idea was to fix it.

RAM Issue

First things first, the machine started up straight into memory test. ROM passes, RAM fails. Most of the RAM fails. I look up videos on youtube, and theirs seemed to have the same crazy pattern with most of the RAM bad. I ordered some replacement chips, and tried a trick I read about of piggybacking a good IC on the bad, walk thru them and find the failed one. That didn’t work for me, I think there was two bad ICs. The chips on the left are the lower 64K so try to fix those first. I used a Hakko 808 to desolder the RAM chips 2 at a time and socket them. I put two new chips in, then moved the other two down. Eventually the last two chips brought the machine to life and it booted straight into basic.

I used a SALT cart to test the RAM. All is good.

But the keyboard….

The keyboard had something spilled in it. The machine looks great from the outside, but keyboard spill damaged the keyboard membrane. This mylar sheet has contacts that mate to the keyboard keys. The mylar looked good, but tested bad. At the edges of the contacts it deteriorated where it’s between two sheets. Repair would be daunting, since there was at least 15 bad spots on the thing:

I contacted BEST Electronics, but didn’t notice the email timely. I bought a replacement (mine is a mitsumi keyboard, however the mylar did not say mitsumi or have a part #?) The replacement was around $30 shipped. It feels less thick than the original which worries me long term, but it works 100%.

With these two things fixed, the 130XE is 100% working.

In the process I also ended up repairing two 1050 floppy drives and built a SDrive-MAX! More on that next posts.

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