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Adaptec AHA-2940UW SCSI controller rescue

Dagwood

Experienced Member
Joined
Oct 16, 2018
Messages
64
A little Sunday morning adventure...

I've been messing with an Adaptec AHA-2940UW controller that in various machines would either lock the machine at the point that the SCSI BIOS should kick in, boot then freeze, or boot and the DOS Adaptec flash utility would say no BIOS present when trying to update it. Attempts to dump the BIOS using Adaptec's flash4.exe resulted in binary data that didn't look anything like a BIOS downloaded from the web.

This has one of those small PLCC-32 EEPROMS, not a DIP type so desoldering then dumped ROM contents with a programmer. The contents resembled but didn't match the dump produced using the flash software. I erased then programmed the chip with the BIOS I downloaded from the web (v2.2 I think) and it verified okay, so probably not a bad EEPROM. I then figured if I've got the chip off I might as well socket it so salvaged a PLCC socket from an unknown board in the junk bin.

Put it all back together, socketed the EEPROM, and was greeted with the SCSI BIOS at startup. So, I guess it was a corrupt BIOS, a bad solder joint, or maybe just a compatibility issue (but I tried it in many machines). It's always a nice feeling to bring something back into working order.

That is all.

AHA-2940UW-BIOS-EEPROM.jpg
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
39,806
Location
Pacific Northwest, USA
You have to wonder if the empty 32-pin DIP pad area is an alternate EPROM location. I haven't looked at my UWs or U2Ws to see if either uses a DIP instead of a PLCC.
 

Unknown_K

Veteran Member
Joined
Sep 11, 2003
Messages
8,580
Location
Ohio/USA
Some of those have Mac EPROM. I don't recall if they can be used in both PCs and Macs or just one or the other (I think both).
 

Dagwood

Experienced Member
Joined
Oct 16, 2018
Messages
64
You have to wonder if the empty 32-pin DIP pad area is an alternate EPROM location. I haven't looked at my UWs or U2Ws to see if either uses a DIP instead of a PLCC.

The pins of the PLCC-32 EEPROM connect to the DIP-32 footprint pads so it is probably an alternate location.
 

GiGaBiTe

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Joined
Apr 30, 2015
Messages
2,779
Location
Austin, Texas
Some of those have Mac EPROM. I don't recall if they can be used in both PCs and Macs or just one or the other (I think both).

A Mac card will not work in a PC and vice versa if it has an option ROM, the firmware has to either be compiled for PowerPC or x86. Sometimes both firmwares existed and it is possible to flash a card to work in either or. Reflashing PC cards was a common occurrence back in the PPC era because the Apple versions were often 2, 3, 4 or more times expensive because "apple tax". Some vendors implemented "hardware DRM" to prevent users from flashing PC cards to work with PPC Macs because it cut into their lucrative pricing structure.

Cards without option ROMs (eg. Voodoo2) will work on any architecture so long as there are drivers available.
 
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