General Category > Lisa Troubleshooting and Repair
Lisa Sun Remarketing scsi card 92 error
AlexTheCat123:
--- Quote from: stepleton on June 12, 2025, 01:51:42 pm ---Component golf challenge: you're MacGyver, the 2732 is missing, and you don't have an EPROM burner anyway. You need to reproduce the ROM with TTL ICs, discrete transistors, and/or passives --- or at least (it sounds like) you need something that returns 00 1B 00 00 00 00 00 00 00 00 for addresses 0..9. How do you do it? Note that use of a 74LS68[2/4/5/7/8] e.g. or similar is basically cheating :-) Highest marks for lowest BOM cost.
--- End quote ---
Here's what I came up with. Not sure if it's the most optimized design possible, but it's something! It just consists of a 74LS04 hex inverter, 74LS08 quad 2-input AND gate, and a 74LS245 bus transceiver, and will produce the pattern 00 1B 00 00 00 00 00 00 00 00 00 00 00 00 00 00 repeatedly as you increment through the ROM's address space.
The top circuit in the Logisim screenshot is the design expressed in terms of gates, and the stuff on the bottom is the schematic using the actual TTL logic chips. The real design uses more gates than the one on the top because of the LS245's active-low enable pin that isn't represented in the top design.
To avoid having to add another chip, I omitted the RD signal that's used on the EPROM's /G pin and I'm only using /SLn for chip selection. I'm operating under the assumption that nothing will ever try to write to anything in the lower half of the card's address space since the only thing there is the EPROM, and this should hopefully be a safe assumption.
The parts cost comes out to $2.81, less than a single 2732 from most online sources, so not too bad!
bmwcyclist:
So...
Is it a 2732 or 2716??
I see lots of variants, -b, etc Should any version work?
--- Quote from: sigma7 on June 08, 2025, 07:27:58 pm --- program a new one if your friend has some on hand - it is a 2716.
--- End quote ---
--- Quote from: stepleton on June 12, 2025, 01:51:42 pm ---
Component golf challenge: you're MacGyver, the 2732 is missing, and you don't have an EPROM burner anyway....
--- End quote ---
AlexTheCat123:
Either one will work. The 2732 is twice the capacity of the 2716, so you'd just duplicate the ROM image to fill the entirety of the ROM if you used the 2732. I believe the ROM file I sent you is 4K though, so it's the proper size for a 2732 to begin with.
And yeah, any variant should work!
Lisa2:
--- Quote from: bmwcyclist on June 06, 2025, 11:14:31 am ---I just recieved a new Sun Remarketing Lisa SCSI card from Vintage Micros.
The card looks great but it is giving me a Card Error 92 on bootup.
--- End quote ---
bmwcyclist,
I am sorry you are having issues with this board from Vintage Micros. Normally these boards are very reliable, you should not have deal with this much trouble to get it going.
On behalf of Vintage Micros, I will repair or replace your defective SCSI card. Please PM me and we will get you fixed up.
Thank you,
Rick
bmwcyclist:
Rick, thank you for the offer!
John is currently working on a CPU card for me, so I don't want to bother him just now, and I don't mind troubleshooting the SCSI card, I am learning a great deal.
I have been in IT and IS since the mid 1990's but always on the networking and security side, never low-level hardware or development.
But if I don't get it working after the ROM experiments I will get in contact with you. Thanks!!!
--- Quote from: Lisa2 on June 25, 2025, 11:49:32 am ---
--- Quote from: bmwcyclist on June 06, 2025, 11:14:31 am ---I just recieved a new Sun Remarketing Lisa SCSI card from Vintage Micros.
The card looks great but it is giving me a Card Error 92 on bootup.
--- End quote ---
bmwcyclist,
I am sorry you are having issues with this board from Vintage Micros. Normally these boards are very reliable, you should not have deal with this much trouble to get it going.
On behalf of Vintage Micros, I will repair or replace your defective SCSI card. Please PM me and we will get you fixed up.
Thank you,
Rick
--- End quote ---
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