Mike's PCjr Page

Hi.
I keep reading that Tandy graphics are essentially the same as those of the PCjr, yet whenever I choose Tandy graphics in a game (such as FS3 for example), the screen image is marred by horizontal black lines. Is there a patch available to fix that problem?

Walid

Have you done the Tandy modification to the hardware first? Tandy borrowed from the PCjr on the video card, but enhanced it too. There is a relatively minor modification to make the PCjr more 'Tandy' compatible.

(I've not bothered doing it, but I know there are docs floating around.)


Mike

Would it affect the standard PCjr graphics operations?

Walid

There's a switch to enable or disable the modification.

I did it on one of my machines. I can't say I ever noticed the difference. It only makes sense for a few games that we coded to take advantage of the Tandy enhanced graphics capabilities. Personally, I don't think it's worth it and remain saddened by the hole and dorky switch installed in the back panel of my original machine....

Would you happen to remember the procedure for the modification? I actually have a couple of games like FS3 and Silent Service II that have a Tandy graphics option that I would like to try. Since it is a switchable option, I don't see the harm in having it available.
I have looked all over the internet for the instructions of that hack and could not find an actual document. All I know is that it involves an LS 7400 family chip piggybacked to another chip and a few jumper wires...

Walid