Author: Marcelo Pires (200216039072.user.veloxzone.com.br)
Date: 01-31-2005 17:57
Hello people,
Thank you all very much for all the information.
I finally suceed in booting my new MegaST this weekend ! :)
As i'm not familiar to the Atari ST platform, i think the computer was fine from the beggining, except for some minor hardware problems, that i corrected.
In various resources on the web, the pinout for the video connector on the MegaST points the pin 2 as "composite video". But that is wrong ! The pin 2 is actually "composite SYNC". So i tried to wire the pin 2 to the composite video input in my Commodore 1084S monitor, and of course, no image came up.
Then i've found a schematic diagram of the Mega, and decided to make the RGB cable to wire my 1084S. And then i found the hardware problems in the video circuit.
The monitor wouldn't sync at all. I've found the Red buffer transistor defective, and the glue logic chip had a bad contact with his socket. So i replaced the transistor and cleaned the glue logic chip, and finally had a crisp image from my 1084S :).
I'm still waiting for my keyboard to arrive, so i couldn't load any program. But i'm really looking forward to try some programs, and try to create some bootable floppies. I really want to try out some demos.
Regarding the Blitter chip, some guys at the comp.sys.atari.st.tech group told me that the NVDI (is it spelled right ?) is faster in software than the blitter in hardware. Is that true ? If yes, i'll try it out.
What i want most is to install a harddrive in this machine, but i'm in a low budget and can't afford the high price of the adapter board and the TOS 2.06 chips. Best Electronics have both. But they are a bit pricey for me right now. And i can't find anywhere in the internet some cheap DIY ACSI-SCSI adapter.
In fact, so far i miss more information regarding DIY in the Atari ST. The Amiga plataform have abundant information on that matter.
Kind Regards,
Marcelo Pires
|
