IBM
Overclocking, 640k hack & repair IBM 5160 XT
Overclocking, 640k hack & repair IBM 5160 XT
#Overclocking #640k #hack #repair #IBM
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You can use cut brass rod segments to fix the drive doors.
When cleaning damage, do you use low-melt solder or regular solder for the cleaning up? Of course you use regular solder when you do the actual repairs, replace components. Also, what about use vinegar to clean up corrosion?
Those old plastic clips are still useful today in modern mainboards. Some have extra mounting holes which don't strictly match the ATX layout specifications. Clip the button of the bottom of those old standoffs and then install it into the mainboard to provide additional support 🙂🤷♂️
This PC isn't rare enough to use a Dremel on its security screws.
I like the white vinegar method for the battery damage 🙂
Some advice I learned from MikeTech, ChipQuik desoldering alloy can help you not have to heat up boards to near destruction levels to get stubborn component legs out, it’s like $15-30 USD for a decent length of the stuff
If you wanted to identity that oily residue as battery acid maybe try one of those pH test strips. Great work!
I haven't repaired an XT since the mid 90s, too soon for those "nasty little Vartas" to cause trouble for me, but what headaches they cause now.
You can always install and run Windows 3.0 in Real Mode, it even fits 10MB harddrive space. That is what you can do.
The ram expansion is most likely not working, cause you did the 640k hack… there will be conflict with the memory address map, where part of the ram on the expansion will overlay part of the ram on the motherboard and the CGA card, it would not just "ADD" to existing. That 4 DIP switch on on the Memory Expansion card is most likely to set where its memory address map starts, which is likely set to be addressed after the motherboard's 256k (or whatever it came with, which was not stated since it looks like there was already a ram upgrade done). Because the CGA's memory will get mapped in the hole between 640k-768K up to 1mb region (the expansion card conflicts with this and why there is no post with the expansion card in), and this cannot be changed… thus causing a conflict with the Memory expansion, cause prior to the hack the Memory expansion was mapping to the 256-512k region. BUT in most cases these cards cannot be set to map above 640k, only between 128k-512k as this predates XMA and EMS. If you want to use this card for the I/O you would need to disable the ram expansion part entirely. Or figure out some way for the memory expansion to map to an address above 768k.
I'm older than that computer
The bulk of RAM expansion cards I've encountered seem to just be intended for backfilling RAM up to 640k that are not on the motherboard (like in your case from the 256k boundary to 512k or 640k). There were some AST cards that allowed you to cram additional RAM into the upper memory area and you needed a driver to push portions of DOS into that section since himem.sys just wasn't a thing yet back then. Most of the modern replacement cards you can get today support backfilling all the way to the 1MB boundary.
Caveat with that is that the system ROM occupies the top of that area so you can't use that for RAM. Same with video and any addon ROMs that are also mapped into the area above 640k so it requires some areas to be excluded from RAM. So in reality you won't be able to get an extra 384K of additional memory but still quite a bit (depends on the system and how the upper memory is mapped). DOS 6.22 pushed into the UMB with the right driver will give you 630k available conventional RAM if I recall, which is a lot for an XT 🙂 I'd have to check my system but I think it gives like 90k available UMB after DOS/all drivers are loaded and then 630k available conventional.
"I almost forgot the speaker"
LMAO in my case it would be "ooops I "accidentally" put the speaker in the trash"
Didn't IBM switch to placing a physical 1MB on board at some point? I vaguely recall a mod to enable sections of upper memory. I'm curious if that would work on this older model.
You forgot the disclaimer when opening a power supply…
if you have a 3d printer you could put it on the bed to keep it at like 100 degrees or so. lol
Do you have an ultrasonic cleaner?
PLS PLS HELP ME to repair my XT boards (x2)
Have had a deal with something like this machine, EC 1842 made in Eastern Germany. Don't know still what was inside it but woah it hadn't a hard disk drive at all, simply two 5.25s
Sponsored by Amalgamated Flux Corporation. "AFC – You can never use TOO much flux."
Good tip for desolder:
Use some flux, take out your solder iron and re-heat all joints with a little fresh solder.
After that desoldering goes like a breeze.
13:44 looks like you damaging that PCB. probably your desolder gun tip is to wide or to big.. Underside only have to touch the through holes.. If tip is to big pcb damage may happen.
That why i dont use those cheaper desolder stations, but using a Weller WMD-3 rework station.
It happen me once when i use the wrong tip to.. But have learned from it.
ISA slot is easy to clean when remove it from the board and put it in a plastic tub and vinegar in it.. Have to soak for 4 hours.. Then take it out and scrub with a tooth brush..
If it is hard dirt, then put it in a plasic tub with Isopropanol 99% and let it soak for a whole day.
If you get it out, then it is almost clean.
Adrian from ADB did a video on repairing those floppy drive doors and 3d printed parts to fix them:
https://www.youtube.com/watch?v=KGuJ185u5f0