• Please review our updated Terms and Rules here

Ti-99/4a restoration help


Experienced Member
Oct 22, 2019
When collecting, you cant always be picky especially when finding any vintage pc in your area is a extreme long shot, so when I got a solid lead on a TI-99, i jumped on it and bought it.
But this thing is nasty, like I think it was buried in a hoader house with the amount of crud on this and it looks like something was spilt on it. I havent cracked it open yet, but I have a feeling that some liquid will be all over the power switch section of the board.
While im restoring this, is there any major hardware issues to look out for? Like Macs being know for cap issues or vic20s might have a VIC chip problem. I dont want to scour this and have it not work because something i overlooked.
Or any tips for restoring one/modding one in terms of replacing parts, patch wires for possible weak traces etc.
The TI-99/4a motherboards are fairly solid and should be easy to clean. The main annoyance is that if it does not start up, it's just trial and error unsoldering chips finding the faulty component.

The metal RF shielding tends to rust. Be aware that the video chip is supposed to have heat sink paste on it and touches the heat sink on the top of the RF shielding. It will not overheat when everything is apart, so testing it without the shielding is fine.

If it came with the power brick, I would test the power brick first and then the power supply. Make sure it is plugged in to a bar strip or something that will shut off in case of a short.

I don't know about cleaning the keyboard, they used various different keyboards with different kinds of key switches. I'd probably just soak that in isopropyl alcohol and hope for the best. Do be careful connecting or disconnecting the keyboard as the connector wires can break easily.
I dont like the unsoldering part...if anything thats my weakness when repairing pc's. This one is the later release beige model, (not the cool metal and black plastic), so hopefully the keyboard is a normal one with no oddball teardown methods.
And good call with the power supply...i haven't gotten to disassembly but I'll test that first before I do anything.