GVP Impact A500 Series1 SCSI CF card adaptor help

[Mamejay]

Hey everyone,
Been a long time reader of the forums but seeing I have gotten back into my Amiga gear thought it was time to join.

I currently have a Amiga 500 and a Impact A500 series I drive.
I have been reading about people added a SCSI CF card reader to their A590 sidecart drives and having good success with this.  A rom update is also required from what I have read.
Below is the unit I have
http://amiga.resource.cx/exp/impact500scsi2
My question is has anyone done this upgrade to their A500?  If so what was involved?
I have found an updated rom for this drive and are waiting on a EPROM burner to arrive.  The two rom chips on the auto boot boards from what I can read are 27C64 for the upper rom and 27C644 for the lower rom.
The above site I mentioned has a link to an updated roms file.  I could only find 27C64 roms and could not find any information on the 27C644 roms.  Are these both the same?  Also with the updated rom the HEX file is 45k and from what I can tell the current eprom chips are only 16K.
What would I need to update the roms in this?
I know I am asking a lot and I thank everyone for their time.
Long Live Amiga!!

[Mamejay]

Have a scsi card reader from MechWare, no need to update the ROMS it'll work just fine with the A590.

The rom upgrade for the A590 is for what HDD's are supported.

Quote - "Version 6 ROMs only allow hard drives up to 512MB in capacity. Version 6.6 and 7.0 ROMs have been reported to work successfully with drive sizes up to 9GB but you will need at least OS3.5 to use drives over 4GB"

I eventually upgraded to 7.0 ROM's so I could have the larger cf card :-)

I've had a problem though trying to get it to boot from the cf card on it's own with the pcmcia adapter. It's possible apparently but the method that is supposed to work doesn't work with my setup so can't fit the entire card reader inside the case.

Thanks for the reply.  I do not have an A590.  I have an Impact A500 drive.  Would this be similar to the A590?

[Mamejay]

I have  GVP Impact 1 for the A2000 with 3.15 ROMs connected to CDROM, 1 Gb HDD, and one of Mech's SCSI card readers.. It boots off a 4 Gb CF card fine; this how I boot into 3.1, 3.5 & 3.9.

Awesome!!  Can you tell me what eprom you used to burn the 3.15 rom?

[Mamejay]

Hey guys,
i am a little confused.  What is the PAL upgrade you talk about?

[Mamejay]

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.

Thanks for that.  It all makes sense now.  There must be someone who has the code for this.  I was reading a GVP FAQ about this and it says that you can leave the odd chip in and just replace the even with the 3.15 eprom.  Has anyone tried this?