GVP Impact A500 Series1 SCSI CF card adaptor help

[orcish75]

You'll need a 27C128 for the 3.15 image. You don't need to split it into odd and even, just burn it into one 27C128 and plug it into the even socket. Unfortunately if you don't have an updated PAL on your A500-SCSI the 3.15 ROM won't work. I'm still trying to source this PAL as I'm trying to upgrade my A2000-HC+2 which is identical to your A500-SCSI but it's for the A2000.

Definitely worth a try though, the 3.15 ROM makes your controller a lot more useful, you can use drives bigger than 4GB (Using a direct-SCSI filesystem like PFS3-DS), CD-ROM drives, SCSI CF readers etc..

[orcish75]

The PAL (Programmable Array Logic) chip is an IC whose logic gates can be programmed, thus saving space on a circuit board.



The chip marked U33/4F99 is the PAL chip that'll need replacing. It handles the addressing for the two ROM chips. The PAL upgrade will perform the addressing for only one ROM chip which is required for the 3.15 ROM.

[orcish75]

Yup, the 3.15 ROM is only one chip, plug it into the even socket. It's still worth a try getting a 3.15 ROM and plugging it into your GVP controller even though you've probably got the old PAL. You might get lucky.