r/ti994a • u/Ninjatrombonist • Aug 26 '26
TI-99 no color issue
I just got a TI-99 and a new power supply for it, but I'm only getting black and white video. I've read conflicting info about whether or not an av cable that is commodore 62 and vic-20 compatible will work with the TI-99. Here's a link to the cable I'm using: https://ebay.io/m/nZ7wfY
I know another possible issue could be a failing crystal, but I wanted to rule my av cable compatibility first. Should this cable work?
3
u/Beautiful-Location74 Aug 27 '26
It's a common problem with machines that use the TMS9918A video chip. The crystal that drives the NTSC color burst frequency can deteriorate with age, causing the video signal to fall out of spec.
There's a fine-tuning adjustment you can try. If that doesn't work you need to replace the crystal.
More info: https://www.pagetable.com/?p=672
1
u/19RockinRiley69 Aug 27 '26
Man oh man I worked hard for the 99 bucks I used to by my ti99-4a! I played a lot of zaxxon on it! I am impressed that it even works for you!
1
u/DuckeyPi Aug 28 '26
My B&W TI-99/4a baffled me until I changed the crystal. I had swapped TMS 9918 and the video ram, but only the crystal was the culprit.
1
1
u/Ninjatrombonist Aug 29 '26
Hmm, I replaced the crystal with a new one and still no color!
1
u/Ninjatrombonist Aug 29 '26
I'm a moron! I replaced the wrong component with my new crystal. Put that old component back and replaced the correct one and now I have color!
1
u/curtludwig Aug 27 '26
I can confirm that the cable for the TI is the same for Atari and Commodore.
5
u/smheath Aug 26 '26
Are you using the composite input or chroma/luma? If this is an NTSC model, it only outputs composite. And the pin that outputs luma on a C64 outputs 12V on the TI for an RF modulator, so definitely don't plug that one into your monitor.