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Re: Atari Mega ST 1 Rev 1 no boot
Posted: 11 Mar 2025 10:11
by Dwh18
stephen_usher wrote: 11 Mar 2025 07:51
Sounds like you need to put a terminal on the serial port and use the diag cartridge. It’s failing before it can properly display anything on the screen.
However, having a red screen is a positive sign as that means that it’s reading the ROM and starting the diagnostics.
Well, that's another issue.... already tried that only getting some (not many) garbage on screen... already tested cable with another Atari and all good
Re: Atari Mega ST 1 Rev 1 no boot
Posted: 11 Mar 2025 11:01
by stephen_usher
This suggests that the system can't talk to the MFP (68901) correctly or the MFP clock isn't working. Check pins 17 and 18 for oscillation from the crystal circuit. It should be 2.4576MHz.
Re: Atari Mega ST 1 Rev 1 no boot
Posted: 11 Mar 2025 12:32
by rubber_jonnie
Dwh18 wrote: 11 Mar 2025 10:11
rubber_jonnie wrote: 11 Mar 2025 08:30
So is it a completely black screen or a black screen in low reswith a white border?
@stephen_usher is right about the the red screen.
COmpletely black screen
RAM errors tend to show as a white border and black screen, I think you have something entirely different going on.
I'd try looking at what
@stephen_usher has suggested.
Re: Atari Mega ST 1 Rev 1 no boot
Posted: 26 Mar 2025 20:48
by Dwh18
Well, almost quitting and leaving this Motherboard and searching for a new one... anyone in EU that repairs Ataris?
Re: Atari Mega ST 1 Rev 1 no boot
Posted: 26 Mar 2025 21:03
by PhilC
Dwh18 wrote: 26 Mar 2025 20:48
Well, almost quitting and leaving this Motherboard and searching for a new one... anyone in EU that repairs Ataris?
If you do decide to give up with that motherboard, then please send it to me, id like to have a look at it and would post the results on the forum.