Oddbean new post about login | logout It seems the Lisa thinks it only has 128Kbytes of memory, according to these memory locations ($294-297 maximum physical address and $2A8-2AB total memory). Need to look into the boot rom to see how memory size is determined. #AppleLisaClone #RetroComputing https://files.mastodon.social/media_attachments/files/111/129/014/874/572/250/original/662cb362e94f356f.jpeg
This is curious: @96d079fd also has a SunRem 2MB card that hasn’t worked either. And combined with an Apple 512K card, was also able to produce an error 45. https://mastodon.social/@iconicbits/111131652337404316
@8ff2c4ef @96d079fd I have an original working Sun board - I can take some measurements later. You asked about what my PCB looks like? http://www.compu85.net/stuff/Lisa/PCB%20Photos/MEM_F.pdf I built that board out, but it didn't work. I never dug into why :S
@16340ea3 @96d079fd Thanks! That’s three now that started bare, built up, and don’t work. Is this a known issue with these boards?
@8ff2c4ef @96d079fd I just assumed I'd done something wrong, or used the wrong part someplace 😅
@16340ea3 @96d079fd Same here. The odds of that are getting less it seems. I wonder how many more have this issue?
@16340ea3 @96d079fd Looking at the BOM and the card, I didn't notice that U5,6,7 was S373 and U9,11 was LS373. I got all S373. How critical is that? What did you folks use on your cards?
@8ff2c4ef @16340ea3 I have LS in U9,11 and S in U5,6,7 per the BOM.
@96d079fd @16340ea3 Can you get into Service Mode (CMD-S) and read memory locations? What do you get for $294-297 and $2A8-2AB?
@8ff2c4ef @16340ea3 Does this have what you need? https://files.mastodon.social/media_attachments/files/111/132/765/667/558/270/original/2448139a45aed69c.jpeg
@96d079fd @16340ea3 Looks like your total RAM is also showing as 128KB just like mine. What type of RAM are you using? Can you share a photo of the board?
@8ff2c4ef @16340ea3 Sure, here's a photo of the board with the 80ns NMBS marked RAM, and 120ns Samsung (just two modules of the set shown). https://files.mastodon.social/media_attachments/files/111/132/818/286/582/148/original/5ae59b4bf5075ff2.jpeg https://files.mastodon.social/media_attachments/files/111/132/818/846/445/855/original/6d5bf30e7be1de46.jpeg
@96d079fd @16340ea3 Thanks! I have those NMBS modules as well and so far they are the only thing that’s close to working. I have two other sets (OKI and Fairchild) that don’t seem to work.
@8ff2c4ef @16340ea3 I looked through my notes and NMBS is what VintageMicros provided in the kit. The Samsung modules I picked up later hoping it was a RAM issue.
@96d079fd @16340ea3 Good to know, thanks!
@8ff2c4ef @16340ea3 I'm not sure how useful this is, but here's a photo of a Rev "A" SunRem board I saw on eBay a while ago - a little different layout. https://files.mastodon.social/media_attachments/files/111/135/679/236/105/994/original/164286e51335cd00.jpg
An #AppleLisaClone side note: this may be a source for the weird open-side expansion board edge connectors. https://edac.net/series/737?fid_p=56&fid_8784=Dual+Row&fid_8785=P.C.+Tail&fid_8788=.550%22+%2813.97mm%29+Notched+Ends Mouser has the high-point contact short-tail version in stock. Almost $10/ea! O.o https://www.mouser.com/ProductDetail/587-737-056-525-206
I asked VintageMicros what kind of memory should be used in the SunRem 2MB RAM card. They sent this picture of SIMMs. The top module looks like the chips are NEC D41256L-12. The sticker says 70ns but doesn’t the -12 denote 120ns? #AppleLisaClone #RetroComputing https://files.mastodon.social/media_attachments/files/111/133/214/933/582/592/original/d5ddfac8bed913f7.jpeg
@8ff2c4ef It looks like the stickers might be from a reseller ... as far as I'm aware -12 is 120ns.
