TI-99/4 bad video.

[ianoid]

That's right, a 99/4, not a 4A.

 

I have a unit with bad video. It seems to start up with jumbled random text. Seems to respond to keys, and carts work, but all graphics are jumbled.

 

Is this an easy obvious fix?

 

I tried the unit with multiple power supplies.

[dphirschler]

Does it look like this?

 

http://atariage.com/forums/topic/228756-diagnose-this-sick-ti/?do=findComment&comment=3053085

 

 

Darryl

[Omega-TI]

Every TI with video problems so far was easily fixed by plugging in << THIS >>.

If you don't wand to go that route, you'll have to spend valuable time trying to hunt down the culprit then order parts and get the soldering iron out and hope that fixes it. Good luck.

[+mizapf]

Compare your screen output with our "bad gallery" at http://www.ninerpedia.org/index.php?title=Troubleshooting

[+Ksarul]

If everything works except for the garbled video, you definitely have a bad VDP RAM chip or two. If you look here and here, you will find the original TI troubleshooting guide for the 99/4. You need both halves to get the complete manual.

Edited May 30, 2016 by Ksarul

[+OLD CS1]

If everything works except for the garbled video, you definitely have a bad VDP RAM chip or two. If you look here and here, you will find the original TI troubleshooting guide for the 99/4. You need both halves to get the complete manual.

 

Any reason why it is not in one piece? I have the ability to combine PDFs.

[+Ksarul]

I just scanned it in that way based on available time--and never took the opportunity later to combine the two files. That size also made it small enough to send as an email attachment to the person I scanned it in for initially.

[+OLD CS1]

I just scanned it in that way based on available time--and never took the opportunity later to combine the two files. That size also made it small enough to send as an email attachment to the person I scanned it in for initially.

 

I dig.