built, worked for a little and then...
Posted: 06 Aug 2021, 00:56
hello,
I finally got the PCB and built my Gigatron TTL. I mixed LS and HCT parts (I used the LS I had). The ROM is v. 5A. I checked all the used parts with my TL866 eprom programmer, including the RAM chip. Apparently every used chip I put was fine.
I used a 6.4 MHz crystal (I didn't find the 6.25 MHz here in Brazil).
I was pleased it worked since the beginning (I get the menu) but immediately I got some issues. Well, at least it boots!
First: the Picture option doesn't show a picture at a time: instead, the three images are smaller than the screen, overlapped (you can see the three images on the screen, sometimes more times every images... do you know the pictures of your son/daughter on your fridge? LOL) and endless scrolling from right to left. Maybe it's the correct behavior? I've seen the 8 bit guys one with the pictures shown one at a time (but he had an older rom version...)
Second: no matter the option (pictures, fractal, etc.), after a while the screen becomes black, then come back, then goes black again, until the computer freezes (the blinking sequence stops suddenly).
I was wondering if it could depend on the RAM chip... did anybody experience a similar issue?
cheers,
Giovi
I finally got the PCB and built my Gigatron TTL. I mixed LS and HCT parts (I used the LS I had). The ROM is v. 5A. I checked all the used parts with my TL866 eprom programmer, including the RAM chip. Apparently every used chip I put was fine.
I used a 6.4 MHz crystal (I didn't find the 6.25 MHz here in Brazil).
I was pleased it worked since the beginning (I get the menu) but immediately I got some issues. Well, at least it boots!
First: the Picture option doesn't show a picture at a time: instead, the three images are smaller than the screen, overlapped (you can see the three images on the screen, sometimes more times every images... do you know the pictures of your son/daughter on your fridge? LOL) and endless scrolling from right to left. Maybe it's the correct behavior? I've seen the 8 bit guys one with the pictures shown one at a time (but he had an older rom version...)
Second: no matter the option (pictures, fractal, etc.), after a while the screen becomes black, then come back, then goes black again, until the computer freezes (the blinking sequence stops suddenly).
I was wondering if it could depend on the RAM chip... did anybody experience a similar issue?
cheers,
Giovi