Dead TT030 Repair

[grunwald]

I was referring to other users having the same error code. :)

[Cyprian]

Went back last night and focused on SEL and BNK5 signals. The following chart shows how memory is mapped dependent on whether the 2/8mb board is installed. The jumper on the board determines the state of BNK5.

interesting.
where did you get this documentation?

[grunwald]

"TT MCU" on docs-dev

[Cyprian]

"TT MCU" on docs-dev

great, thanks

[grunwald]

It turns out that the Ctrl-Alt-Del issue was the keyboard. The Ctrl key is not registering.

[czietz]

It turns out that the Ctrl-Alt-Del issue was the keyboard. The Ctrl key is not registering.

Perhaps check the keyboard membrane. When Ctrl stopped working on one of my TT keyboards, it was a damaged trace:
https://forum.atari-home.de/index.php/t ... #msg262044
... that I repaired:
https://forum.atari-home.de/index.php/t ... #msg262075

Since the damage was underneath the green protective layer, I suspect a manufacturing defect that grew worse over time.

[stephen_usher]

The other issue with the Mitsumi keyboards is that the conductive carbon impregnated rubber stops being conductive and you have to use carbon paint to fix it.

[atari030]

I have the misfortune of have a TT and 2 MegaSTE KB's that need repairing. I figure the hassle of conductive paint repair might be easier than going to Best for three replacement mylars. I've not used conductive paint before, is there any specific type/brand to look at or are they much of a muchness?

[grunwald]

I had a similar issue with one of my other keyboards. I fixed it at the time with thin copper tape and conductive epoxy. I used MG Chemicals 8331 which I had from another project. It works great but it costs more than a replacement mylar! I also picked up a new mylar from Best on my last order when I noticed they were back in stock. I'll pull the keyboard apart when I get a chance and repair or replace the mylar. The memory card issue is the one that's keeping me up at night....

[stephen_usher]

If it’s the conductive rubber which has gone bad then changing the mylar won’t help.

When I did my TT keyboard I used the stuff that Exxos used to have in his store (but doesn’t sell any more).

I’ve got a remote control I need to fix and I’m going to experiment with Graphit 33.