Recent content by mikeyp

Hi both Some info that may help. I followed the instructions here to modify the modules. http://john.ccac.rwth-aachen.de:8000/misc/ps2cache/ They were fully tested in a retro chip tester pro (RAM and PARITY tests) and POST tested in my AT. My EMEA card is faulty and can only use 4MB RAM...

New batch of modified modules. IBM Proprietary 256K and 1MB SIMMs are now able to be tested in the retro chip tester pro (HUGE thanks to Stephan at 8bit-MuseumDE): I have done 4 so far: RAM count is currently 4608 KB (Battery is a work in progress):

Standard 30 pin 1M x 9 SIMMs. I've just recieved the batch I was waiting for. They took AGES to ship. I just need time to mod them now. Meanwhile, something interesting has happened. I sent the modules I modded to Germany and the IBM 1M x 9 Parity test and 256K x 9 Parity test are going to be...

It's not a timing thing. It's definitely that they're the IBM proprietary format as used in their PS/2 SCSI adapter with their horrible IBM presence detection. I modded a couple of industry standard sticks as above and they at least register. Sadly I damaged one in the process so am waiting on...

Thank you. I have ordered more ram per option 1. I will wait and see what arrives and report back in a couple of weeks.

Getting somewhere. I performed the surgery on the modules and the error code has changed. It switches if I switch the modules around so either I have damaged one or have a bad solder joint. I cut the trace above pad 26, scraped back the solder mask and joined the trace to pad 29. I cut the...

Damnit. I think you're right. I thought this machine was too early for this tomfoolery of theirs. Looks like my soldering iron is warming up tomorrow then! I looked up a few of the part numbers, settled on 68X5721 - the 1MB SIMM and then came across this: from here...

Can anyone offer any insight into my latest problem please? I have an IBM AT which currently has an AST Advantage expanding it to 640kB. This works fine and POST counts to 640kB. I wish to remove it and add the below: I have bought the board pictured below. It's marked ASM 55X3543 EC A25158...

Cheers for that. Better list them correctly! 😂

Hmm. Ok. Nice to see someone has some reasonably current info on that chip. Digging way back I found this that suggested it was actually a memory chip. https://web.archive.org/web/20130307214429/http://www.telegraphics.com.au/~fthain/dram/index.html but if the above is right then no amount of...

I have been lucky enough to be able to purchase the IBM Enhanced Memory Expansion Adapter for my IBM 5170. I also ordered what should have been 8 3 chip 1Mx9 30 pin SIMMS. They don't work in the 5170... The 1Mx8 non-parity portion tests and passes fine in the retro chip tester pro. The parity...

IBM made the legs hollow but the designer of the 3D printed parts made them solid so I think they will be much stronger than the originals. They do seem very rigid. In my opinion pretty much anything should be fine with standard use. The issue was careless lateral pressure by the previous owner.

I went with Aluminium. It looks so smart and is really strong.

$18 for all the nylon parts. $60 for the aluminium. Note that I’ve only had the legs made up in aluminium and will be using the nylon cylinders whichever option I choose.

You literally called the exact IC from my description and the photos. Not even the colour ones! I would call that pretty jaw dropping!