The Amiga 3000 SCSI BUG!

[vk3heg]

Hello everyone,

I'm looking to replace the buggie/crap scsi controller chip in my A3000. I've been searching via google for a shop etc that sells the WD33C93A chip. having had no luck, I'm now asking you guys on here if anyone has any for sale?

I have also seen a post saying that the WD33C93B-PL will also work?

[vk3heg]

alexh wrote:
Best place to get them from is Centsible

http://www.centsible.com/

26 USDollars

Remember you want a REV8 part.

I'll be using them if the scsi module wont play fair on the Cyberstorm. At the moment when it's plugged in my A3000 wont boot. I'm going to be trying the INT2 hack and hope that it'll fix the problem.

[vk3heg]

adolescent wrote:

BTW, are you sure the problem you're having is related to the proto SCSI chip?  I ran various SCSI devices on the proto with little problem until I tried to run a pair of 7 CD-ROM changers.  

Yes it is. Under Aos 3.9 I get weird scsi problems when accessing the cdrom. When I try and install Debian Linix, it's reporting scsi timeout/disconnect error's and wont install. I have been using scsi for many years and have seen the symptons before on other platforms. (Also having the many amiga websites with information helps.)

[vk3heg]

KThunder wrote:

With any accelerator that has scsi on-board you have to do the int2 hack or you will have a no boot. if the scsi on the board cant trigger int2 then it will foul everything up. there are several symptoms of this: no boot, boot with no scsi capability, boot with no accelerator scsi.

I have now performed the int2 hack/addition to the A3000's motherboard. The scsi module is now working.

A minor problem is that it's SLOW  :-?  compared to the A3000's internal scsi. I'm using a Seagate ST39236LW 68pin (via a 68-50pin converter) 9gig scsi drive. This is the same drive/install of Amiga OS 3.9 from the A3k's scsi controller.

Is there a setting that needs changing to speed things up or will a re-install on the cyberstorm's scsi controller fix things?

[vk3heg]

Zac67 wrote:
Any RAM on the Cyberstorm?
Buffer mask values set correctly to allocate SCSI buffers in Cyberstorm RAM? DMAing into motherboard fastmem or even chipmem will slow down the transfer considerably.

There's 128Mb of ram installed. I had a look at the on-line docs (that got installed onto the hd) and it said to use:

Mask 0xfffffffc
Max xfer 0xffffff

Using these values results on the hd not even booting and the displaying of the "Insert workbench" disk.

What values would you sujest?

[vk3heg]

No one with a Mask value that wont crash/go slow?

[vk3heg]

Zac67 wrote:
A3k onboard RAM grows from 0x07ffffff downwards, with 16 MB ZIPs down to 0x07000000.
Where's the accelerator RAM located at?

The 0xfffffffc should be fine, it means 'any RAM 32 bit aligned' - since faster mem is given a higher priority, that's where it should end up at. Have you tried with a smaller Max Xfer value (0xffff)?
What's the working mask value?

The memory in my A3000 is as follows:

128Mb $8000000 - $fffffff (Cyberstorm)
4Mb   $7c00000 - $7ffffff (Motherboard)
2Mb   $4000    - $1fffff  (Chip)

$40000000 Cybervision64 (4mb on board)
$e90000 Cyberstorm
$ea0000 BSC Multiface 3


A Mask $7ffffffe & Max xfer $00ffffff is nice and fast on the A3000 internal scsi port. It's when placing the HD on the cyberstorm's scsi port that things run *very* slow (there is nothing on the A3000 internal port when doing this).

I'm wanting to move the hd to the cyberstorm for two main reasons:

1: So I can install linux, and not get scsi timeout/disconnect error's from the internal port.

2: So that the scsi is running off the accel. card (it should be faster than the A3000s scsi port).