Apple 2gs boots to Monitor prompt with SCSI Card installed

[Severian]

Originally had a similar issue to the person on this thread http://68kmla.org/forums/viewtopic.php?f=6&t=16291 however my issue was resolved when removing the external SCSI terminator as the drive had the resistors on it.

After removing the external terminator, the gs did boot via floppy and the hard drive would mount however after fiddling (i.e. removing the external drive from the card) the gs now boots to about 75% through and then it crashes to the monitor prompt. This now occurs even if the drive powered off or is not connected. Once the SCSI card is removed, the gs will boot with no issues using the same floppy that failed previously.

The 2gs has a rom 3 installed. I've tried booting from an OS 5.4 floppy and an OS 6 floppy, both do the same thing. The SCSI card is the standard Apple one (not high speed) model 607-0291-A with the eprom labeled 2.0. I have it in slot 6 currently but tried it in slot 7 (both are set to "Your Card") and get the same results. The boot sequence is set to boot from slot 5 as I was in the process of trying to get the drive partitioned properly and the OS installed on it.

Did I somehow fry the SCSI controller? Would getting a new eprom for it help? Any assistance would be greatly appreciated. Thanks!

 

[waynestewart]

To work with GSOS your card should be a Rev C. If there’s an original sticker on the EPROM, it should read

341-0112A for Rev A

341-0112B for Rev B

341-0437-A for Rev C

Or if the EPROM is a 2764 then it’s a Rev A or B. A 27128 and it should be a Rev C

The Jumper on the card is normally on the right set of pins.

You could try reseating the socketed chips on the card. Pry them up a little with a small screwdriver or knife and press them back down. That’s to restore contact in cases where the legs have a bit of oxidation.

You’re letting the drive fully spin up before starting the IIgs?

Have you tried changing the drives SCSI ID?

 

[Severian]

Thank you Wayne for taking the time to respond.

The SCSI card I have even though it is an Apple card the eprom does not have the traditional sticker on it, however the markings are 27C128-20JL so looks like a rev C then. The jumper is in the far right set of pins.

To simply troubleshooting, the drive is no longer connected as the boot fails whether the drive is connected or not.

I tried the card in a rom 1 gs and that boots but the drive isn't recognized which makes me wonder if the card itself is even being recognized.

Tried reseating the chips and still it crashed.

So basically it was working, now it isn't. Is it possible I could have corrupted the data on the eprom?

Not sure if this is helpful however there is a bit of code on the screen when it goes to the prompt:

04/BC92: 00 FF      BRK FF
A=42A5  X=0001  Y=0001  S=BCE5  D=BD00 P=00
B=E0 K=04 M=00 Q=BE L=0 m=0 x=0 e=0

 

[waynestewart]

I'm not sure what else to suggest. Could be a drive problem or incompatibility too. Which drive are you using?

Usually I'd have the Rev C in slot 7 and if the drive is turned off then the card is ignored and it boots from the next slot.