So one of the “joys” of working on all this retro-tech is that you never know if it’s going to work when you turn it on. Two of my systems, despite previously working, have developed faults and will need repairs.
This machine has always had me very wary, as it has been hacked, and not exactly neatly or well. I’ve already had to resolder several wires and I am guessing I’ll need to resolder many more.
The symptoms seem to be memory related. Randomly garbage characters start appearing on the screen while I use the machine. I’m assuming something in there is loose.
My planned course of action is to clean up and simplify where possible. The ROM tower is definitely coming out. I don’t do any machine code development, so having 3 different Machine Code Monitors is overkill. I’ll pull it out and leave only the original rom in the socket. I may need to replace the socket, but we’ll see. if the ROM tower has been in there a long time, the contacts on the socket may be damaged.
I’ll then give it another soak test and give the memory expansion a good hard look-over. I’m wondering if it’d be worth my time replacing it with a modern one? The current one is 192k and a lot of “expanded Atari” software seems to want 256k. Maybe desolder everything and install an Ultimate 1MB? I might put it on the list for near the end of the year.
Argh! This machine has become the bane of my existence. Firstly the right controller developed a fault and I have been unable to source a replacement. I have tried building a replacement, only to be foiled by a lack of documentation and some very strange design decisions on the part of the keyboard manufacturers. The joystick innards consist of a long plastic membrane, folded upon itself several times. The conductive ink wears away with general use and the whole thing is a maintenance nightmare. Also, most of the buttons seem to be connected to 3 lines, not 2. I haven’t seen this anywhere else, and I’m hoping it’s just redundancy…
…and then the bug with the video / audio distortion crept back in. I was sure I’d fixed that one too!
My current plan, going forward for this system is to throw it in the bin. Only joking! I’ll strip it down, replace both the 5v and 12 regulators with more modern, low temp replacements. I’ll check for more dry joints and see if I can get it stable enough to boot reliably. the fact that a “bump” fixes the problem still points to it being a dry joint somewhere.
After that I’ll start working on the replacement keyboard again. If I can get the rest of the system stable, I’ll just short out pins until I’ve mapped out the full range of the keyboard matrix and then I should be able to build a drop in replacement. After that I’ll probably look at building a full joystick / keyboard replacement using low profile buttons. These systems have a limited life, so being able to offer a permanent replacement will make life easier for everyone.