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Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 13:41
by amigaricc
Good Day all,
I have been reading some of others black screen post but none of them got me further.
Here is my situation, I have an Amiga 2000 Rev 6.2 with no Battery Damage. I tested all Custom Chips with a working Amiga and they all tested good.
Diagrom has no serial output at all.
So I was wondering what exactly happens when you switch on the Amiga. What does Diagrom need to display something on the serial port?
Thank you for your input
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 13:47
by terriblefire
amigaricc wrote: 29 Mar 2025 13:41
Good Day all,
I have been reading some of others black screen post but none of them got me further.
Here is my situation, I have an Amiga 2000 Rev 6.2 with no Battery Damage. I tested all Custom Chips with a working Amiga and they all tested good.
Diagrom has no serial output at all.
So I was wondering what exactly happens when you switch on the Amiga. What does Diagrom need to display something on the serial port?
Thank you for your input
DiagROM will need Gary to decode ROM, a working CPU and thats about it to get *something* out of the machine. You should see either serial out or screen flashing. You dont need any ram to work, you dont need the CIA's to do much except have a working OVL signal to gary.
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:08
by amigaricc
CPU and Gary have tested fine in another rev 6.4 board. Serial output is just black and screen is black as well.
CPU is getting 7MHz on Pin 15.
OVL Line form CIA (2) to Gary (30) tested fine
P.S. Thank you for helping terriblefire :D
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:33
by terriblefire
amigaricc wrote: 29 Mar 2025 14:08
CPU and Gary have tested fine in another rev 6.4 board. Serial output is just black and screen is black as well.
CPU is getting 7MHz on Pin 15.
OVL Line form CIA (2) to Gary (30) tested fine
P.S. Thank you for helping terriblefire :D
Power LED does what?
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:35
by amigaricc
Power LED remains off, no sign of live at all. Keyboard Caps Lock works
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:39
by terriblefire
The CPU is not running. Or runs for a very short time and crashes.
See if the Halt pin on the CPU changes state. Hold the machine in reset (just short the RESET line to GND) and measure HALT before and after letting reset go.
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:45
by terriblefire
Also look through this thread
viewtopic.php?f=84&t=7067&hilit=A2000
there is going to be a lot of repeat here.
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:48
by amigaricc
HLT (17) no change at all with RST (18) shorten to ground.
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:49
by amigaricc
Yes i have been reading this and was hoping it was the same for me. Followed all the steps as well but nothing
Re: Black Screen Amiga 2000 Rev 6.2
Posted: 29 Mar 2025 14:51
by amigaricc
terriblefire wrote: 29 Mar 2025 13:47
amigaricc wrote: 29 Mar 2025 13:41
Good Day all,
I have been reading some of others black screen post but none of them got me further.
Here is my situation, I have an Amiga 2000 Rev 6.2 with no Battery Damage. I tested all Custom Chips with a working Amiga and they all tested good.
Diagrom has no serial output at all.
So I was wondering what exactly happens when you switch on the Amiga. What does Diagrom need to display something on the serial port?
Thank you for your input
DiagROM will need Gary to decode ROM, a working CPU and thats about it to get *something* out of the machine. You should see either serial out or screen flashing. You dont need any ram to work, you dont need the CIA's to do much except have a working OVL signal to gary.
Does Diagrom need any 74 Logics to run? For example U103 or U540 /U541