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Strike 2 on 2nd TI-99/4A hardware help!
#1
Hi,

I got a TI-99/4A a while back from a friend who thought it was working. When I got it hooked up I got a totally black screen - the only sign that I turned it on was an audio 'pop' when I flipped the power on. I took it apart and checked the IC seating, etc. No change. The sound IC was getting extremely hot, so I figured it for shorted. I have that IC ordered, along with the video processor. Yesterday I read the machine would power up without the sound IC (just like the C64), so I popped out the sound IC. No change - but the TIM IC is getting pretty hot pretty fast as well. After reading online articles, it could be video RAM, the larger motorola brand RAM (2 IC's), or anything else, really.
What I need is info on what IC's typically run really hot really fast.
I know the video processor and the TIM are connected to heat-sink like blocks of metal, so I understand that they generate heat. The question is, which ones get hot fast in a normal working machine, and which ones take a while?

This info will help me decide if the TIM heating up to REALLY hot in about 15 seconds is normal, or if it's another BAD IC. Usually I leave a dead machine on for about 15-20 minutes, then check the RAM, etc. for super hot temps. Those are usually the bad ones. This being my very first TI experience, I don't know the norms.

A lot of the advice I saw online was just to pick up another TI and forget about trying to fix one unless you have access to all of the available IC's inside (most seem to be housed in Korea). I just got one that was listed as 'working', and of course, it's not. Grrrrrrr.

My second TI (the strike 2 in the title) pops up a screen that is grey and rolls like the horizontal needs adjusting on the monitor. I can make out the TI welcome screen, but that's about it. Any ideas? I'm pretty good at fixing most vintage computers, but this is my first run with the TI and I'm completely lost on the in's and out's of their repair. ANY help or answers to these questions would be greatly appreciated!

Thank you!


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Strike 2 on 2nd TI-99/4A hardware help! - by TheRealAnubis - 06-06-2014, 01:05 PM

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