Amiga 2000 Problem

grahamn · 17 March 2022, 15:40

Looking for a bit of advice here.

Amiga 2000 boots DiagRom with no problems, but will not boot from any other ROM (I've tried 1.3, 2.04, and 3.2.1)

DiagROM shows no problems with RAM, CIA, etc., but the kickstart ROMs just go to the first grey screen and then hang.

I've swapped PAULA, DENISE, GARY, AGNUS, BUSTER, Both CIAs, and all RAM (you can see I'm getting desperate!). I can't find any obviously shorted data or address lines.

I can only assume the Kickstart ROMs do something when starting up that DiagROM doesn't, and presume the issue is with one of the logic chips - but I would really appreciate any pointers from the knowledgeable people on this forum.

Many thanks

alexh · 17 March 2022, 15:44

You're absolutely sure that the ROMs have been burned correctly? They work on other Amigas?

Does DiagROM include a ROM test? (Probably not) but perhaps an address line to/from the ROM is broken and DiagROM is too small to trigger it?

Which revision A2000 motherboard?

grahamn · 17 March 2022, 15:58

The 1.3 and 2.04 ROMs are original Commodore ones. They work on other Amigas, and indeed I've tried 3 of each just in case.

There is no ROM test in DiagROM, I've done a full memory test, but that just checks the RAM (and I replaced that anyway just in case).

I couldn't find any address line problems, though I can see why that looks the most likely cause - I'll re-test to see if I can find anything.

It's aRev.6 board.

Thanks

alexh · 17 March 2022, 16:28

Because 1.3 is affected it reduces the number of ROM address lines that might be affected to 256KB (A0->A17)

I'd start from the top address down as the lower addresses would have shown up for DiagROM.

DiagROM 1.2.1 is about half that size (140KiB)

Might hint at the problem being A17 on the ROM socket.

grahamn · 17 March 2022, 16:56

A17 to A12 all look fine. I didn't go any further as it seemed to me that lower address lines wouldn't cause this problem. My suspicion is that the Kickstart ROM is running but checks something on startup that DiagROM doesn't - but I have no idea what! And with a lack of error messages, I'm a bit in the dark. Having tried alternative versions of the main ICs without any change in behaviour, I'm guessing that one of the logic chips is failing.

alexh · 17 March 2022, 18:36

ROMWack? Or does it not even give GURU?

grahamn · 17 March 2022, 19:02

Nothing - unfortunately. Just a grey screen.

cpiac64 · 17 March 2022, 20:24

use diagnostic Logica for test

grahamn · 17 March 2022, 21:12

It was worth a try. Unfortunately, just a black screen.

cpiac64 · 17 March 2022, 22:23

black screen? strange

p.s.
nice info on A17

nogginthenog · 18 March 2022, 19:59

alexh might have a point with regards to ROMWack. Try a null modem connection.

grahamn · 18 March 2022, 21:16

I'm not sure what you mean - I had a serial connection set up for use with DiagROM, and this was still active when I tried the other ROMs, but there was no output over the serial port.

grahamn · 08 April 2022, 09:28

Just to put this to bed, and in case it helps anyone else. I eventually found the problem - there was some minor track damage around R311, R312 which I hadn't spotted as I thought this area of the board was exclusively related to the expansion slots and didn't initially pay it much attention. When I fixed the tracks, everything worked as normal.

17 March 2022, 15:40	#1
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	Amiga 2000 Problem Looking for a bit of advice here. Amiga 2000 boots DiagRom with no problems, but will not boot from any other ROM (I've tried 1.3, 2.04, and 3.2.1) DiagROM shows no problems with RAM, CIA, etc., but the kickstart ROMs just go to the first grey screen and then hang. I've swapped PAULA, DENISE, GARY, AGNUS, BUSTER, Both CIAs, and all RAM (you can see I'm getting desperate!). I can't find any obviously shorted data or address lines. I can only assume the Kickstart ROMs do something when starting up that DiagROM doesn't, and presume the issue is with one of the logic chips - but I would really appreciate any pointers from the knowledgeable people on this forum. Many thanks

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17 March 2022, 15:44	#2
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,480	You're absolutely sure that the ROMs have been burned correctly? They work on other Amigas? Does DiagROM include a ROM test? (Probably not) but perhaps an address line to/from the ROM is broken and DiagROM is too small to trigger it? Which revision A2000 motherboard?

17 March 2022, 15:58	#3
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	The 1.3 and 2.04 ROMs are original Commodore ones. They work on other Amigas, and indeed I've tried 3 of each just in case. There is no ROM test in DiagROM, I've done a full memory test, but that just checks the RAM (and I replaced that anyway just in case). I couldn't find any address line problems, though I can see why that looks the most likely cause - I'll re-test to see if I can find anything. It's aRev.6 board. Thanks

17 March 2022, 16:28	#4
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,480	Because 1.3 is affected it reduces the number of ROM address lines that might be affected to 256KB (A0->A17) I'd start from the top address down as the lower addresses would have shown up for DiagROM. DiagROM 1.2.1 is about half that size (140KiB) Might hint at the problem being A17 on the ROM socket.

17 March 2022, 16:56	#5
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	A17 to A12 all look fine. I didn't go any further as it seemed to me that lower address lines wouldn't cause this problem. My suspicion is that the Kickstart ROM is running but checks something on startup that DiagROM doesn't - but I have no idea what! And with a lack of error messages, I'm a bit in the dark. Having tried alternative versions of the main ICs without any change in behaviour, I'm guessing that one of the logic chips is failing.

17 March 2022, 18:36	#6
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,480	ROMWack? Or does it not even give GURU?

17 March 2022, 19:02	#7
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	Nothing - unfortunately. Just a grey screen.

17 March 2022, 20:24	#8
cpiac64 Registered User Join Date: Apr 2010 Location: Italy Posts: 1,136	use diagnostic Logica for test

17 March 2022, 21:12	#9
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	It was worth a try. Unfortunately, just a black screen.

17 March 2022, 22:23	#10
cpiac64 Registered User Join Date: Apr 2010 Location: Italy Posts: 1,136	black screen? strange p.s. nice info on A17

18 March 2022, 19:59	#11
nogginthenog Amigan Join Date: Feb 2012 Location: London Posts: 1,318	alexh might have a point with regards to ROMWack. Try a null modem connection.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

18 March 2022, 21:16	#12
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	I'm not sure what you mean - I had a serial connection set up for use with DiagROM, and this was still active when I tried the other ROMs, but there was no output over the serial port.

08 April 2022, 09:28	#13
grahamn Registered User Join Date: Aug 2019 Location: Burnham on Crouch, UK Age: 71 Posts: 26	Just to put this to bed, and in case it helps anyone else. I eventually found the problem - there was some minor track damage around R311, R312 which I hadn't spotted as I thought this area of the board was exclusively related to the expansion slots and didn't initially pay it much attention. When I fixed the tracks, everything worked as normal.