Amiga A2090a SCSI card lock up

pioneer · 17 March 2018, 15:08

I have a A2090a in an Amiga 2000. I wanted to see if I could get a very old (1988) 5-1/4-in NEC MFM hard drive to work. I did mount the drive with the "prep" command and formatted and copied workbench to the drive. Everything looked good. "Prep" seems to save the HD settings in the autoboot EPROM. When I rebooted, the amiga screen would flash different shades of grey like it always does. Then it settled on a grey screen. There is no disk activity from the hard drive or floppy drive. This looks like a lockup. When I disconnect the drive and try booting without it, I get the same thing. I put a jumper on J4 to disable the autoboot eprom. That doesn't make any difference. It looks like it's permanently locked up. Any ideas? Is there some way to unlock the card? When I take the A2090a out, the Amiga boots normally. I have a OS 2.0 ROM installed.

Toni Wilen · 17 March 2018, 17:48

A2090a (or most other HD controllers) don't have any config ROMs. Prep only writes to the disk.

Probably bad connection (Zorro slot, chip sockets etc..) if it won't boot even with autoboot jumper removed. Does Amiga boot if you physically remove A2090a autoboot roms?

pioneer · 18 March 2018, 03:00

Thanks Toni. Just to avoid confusion, according to the info I've been able to find, installing a jumper disables autoboot. The theory I have is that the card is waiting for some response from the drive that it isn't getting. It might not have anything to do with autobooting. That doesn't explain why it's locked up with nothing connected. I thought maybe hooking a different drive, which I don't have, might cause it to unlock. I might try removing the autobook chips, there are three. I might also try the card in a different Amiga. I have some others.

Toni Wilen · 18 March 2018, 13:22

Hanging with autoboot disabled guarantees it hangs because of hardware fault.

No autoboot = no rom code executed, no drives detected etc, board is only autoconfigured = mapped to Amiga address space. In this situation drives are only detected when boot floppy disk driver gets loaded.

Removal of both ROMs guarantees it isn't ROM problem. Simple and easy check. If it still hangs: reseat all chips etc, the usual hardware troubleshooting.

Third ROM is for Z80 code (that handles MFM drive), it is invisible to Amiga side. A2090 is special case, it has a Z80 CPU.

17 March 2018, 15:08	#1
pioneer Registered User Join Date: Mar 2018 Location: Salt Lake City, Utah Posts: 2	Amiga A2090a SCSI card lock up I have a A2090a in an Amiga 2000. I wanted to see if I could get a very old (1988) 5-1/4-in NEC MFM hard drive to work. I did mount the drive with the "prep" command and formatted and copied workbench to the drive. Everything looked good. "Prep" seems to save the HD settings in the autoboot EPROM. When I rebooted, the amiga screen would flash different shades of grey like it always does. Then it settled on a grey screen. There is no disk activity from the hard drive or floppy drive. This looks like a lockup. When I disconnect the drive and try booting without it, I get the same thing. I put a jumper on J4 to disable the autoboot eprom. That doesn't make any difference. It looks like it's permanently locked up. Any ideas? Is there some way to unlock the card? When I take the A2090a out, the Amiga boots normally. I have a OS 2.0 ROM installed.

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17 March 2018, 17:48	#2
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,529	A2090a (or most other HD controllers) don't have any config ROMs. Prep only writes to the disk. Probably bad connection (Zorro slot, chip sockets etc..) if it won't boot even with autoboot jumper removed. Does Amiga boot if you physically remove A2090a autoboot roms?

18 March 2018, 03:00	#3
pioneer Registered User Join Date: Mar 2018 Location: Salt Lake City, Utah Posts: 2	Thanks Toni. Just to avoid confusion, according to the info I've been able to find, installing a jumper disables autoboot. The theory I have is that the card is waiting for some response from the drive that it isn't getting. It might not have anything to do with autobooting. That doesn't explain why it's locked up with nothing connected. I thought maybe hooking a different drive, which I don't have, might cause it to unlock. I might try removing the autobook chips, there are three. I might also try the card in a different Amiga. I have some others.

18 March 2018, 13:22	#4
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,529	Hanging with autoboot disabled guarantees it hangs because of hardware fault. No autoboot = no rom code executed, no drives detected etc, board is only autoconfigured = mapped to Amiga address space. In this situation drives are only detected when boot floppy disk driver gets loaded. Removal of both ROMs guarantees it isn't ROM problem. Simple and easy check. If it still hangs: reseat all chips etc, the usual hardware troubleshooting. Third ROM is for Z80 code (that handles MFM drive), it is invisible to Amiga side. A2090 is special case, it has a Z80 CPU.

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