General Category > LisaList2
Sun Remarketing SCSI Card Reverse-Engineering
AlexTheCat123:
A few days ago, I got the idea to reverse-engineer some Lisa boards, particularly the 2/5 motherboard and the Sun SCSI card since the schematics for both of these boards are either incomplete (the motherboard) or nonexistent (the SCSI card). I want to design some replica PCBs that are as accurate to the originals as possible and release the files to everyone in the Lisa community so that it's easy and inexpensive to replace a damaged board. The motherboard is coming along really well and it's pretty easy to fill in the gaps in the schematic since I have an actual board to probe around on with the multimeter, but the SCSI card is a lot more difficult since there isn't a schematic for it and I don't actually have one of these cards, so I'm just having to follow the traces on the board around based on pictures I've found online.
It's tedious, but I've made good progress with most of the board thanks to the pictures I found on Bitsavers, the low-res but still somewhat useful picture of a blank board on the Vintagemicros site, and the pictures on this site: http://www.classic-computer-collection.de/de/neue-details/apple-lisa-2-peripherie.html. The only area of the board that I'm struggling with is the area around and underneath U4 and U6, the two logic chips right next to the 4-pin hard disk power connector. None of the pictures (other than the Vintagemicros picture, but it's way too blurry to see anything useful) show the bare board in this area and I was wondering if you guys could help me out here.
Would anybody who owns a Sun SCSI card be willing to desolder those two chips and post some pictures of that area of the board so that I can see all of the traces underneath? If not, I totally understand, but I figured that it wouldn't hurt to ask!
I'll keep you guys posted on any progress that I make with the motherboard or the SCSI card and if these projects are successful, I'm thinking about designing PCBs for the 2-port parallel card next!
rayarachelian:
Here you go: http://lisaem.sunder.net/sunrem_scsi_blank_card.zip
AlexTheCat123:
Thanks Ray! Those are going to be super helpful!
patrick:
Attached is a schematic of the Sun Remarketing SCSI card.
I also have (redrawn) Eagle design files for the card. Twenty years ago I had built my own copy, with self-etched board and Quickboot-compatible EPROM. However, I never published the data because Sun Remarketing was still in business then. So it remained limited to personal use.
jamesdenton:
--- Quote from: AlexTheCat123 on February 02, 2022, 01:40:38 pm ---
Would anybody who owns a Sun SCSI card be willing to desolder those two chips and post some pictures of that area of the board so that I can see all of the traces underneath? If not, I totally understand, but I figured that it wouldn't hurt to ask!
I'll keep you guys posted on any progress that I make with the motherboard or the SCSI card and if these projects are successful, I'm thinking about designing PCBs for the 2-port parallel card next!
--- End quote ---
I have a blank of the SCSI card if you'd like to borrow it for this project. Feel free to DM me.
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