Overclocking, 640k hack & repair IBM 5160 XT
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- Опубликовано: 3 май 2024
- Skinny Sprint Gerbers here: github.com/epictronics/Skinny...
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Tools I regularly use
DeoxIT D5 Contact Cleaner
Hanstar 861DW Rework Station
Pro'sKit SS-331 Desoldering Station
UNI-T UT61E Auto Ranging Multimeter
UNI-T UT890D Manual Ranging Multimeter
MESR-100 mk2 ESR meeter
PINECIL Soldering Iron
PinePowerPSU
TS-100 Soldering Iron
AMTECH NC-559-ASM Flux
Kester 951 Flux pen
MaAnt Grinding Pen
Multicore 60/40. 0.38mm and 0.5mm solder
TL866 II Plus Programmer
RIGOL DHO800 70MHz four-channel digital scope
Tektronix 2246A 100 MHz four-channel analog scope
FNIRSI DPOX180H 180MHz Handheld Digital Oscilloscope
InfiRay P2 Pro Thermal Camera
PCBs from PCBWay.com
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Music by Karl Casey @ White Bat Audio 
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The trick to getting those white clips out is to get a BIC pen, remove the ink... and remaining body will fit over white clips, squeezing the clips just so they can pass through the circuit board. Been doing this since the early '90s.
Thanks for that tip.
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 wasn't expecting it to work proper, but I didn't know it could prevent the system to boot. Thanks
stands to reason if its trying to backfill, there's going to be a resource conflict and its going to stall things.
i'd play with the switches and see if some other combo doesn't allow the start address to move out enough to backfill to the 1mb, or yeah, disable it as suggested above.
@@kenabi I think I'll start by testing it in a system with 256k. Switches are probably correctly set for that
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 🙂🤷♂️
Whew, doing that many sockets on one of these boards is brutal. I swear the ground planes are like 1/4” copper sheet. 😂 Great dedication! And nice mod!
Thanks. Yeah, copper must have been cheap in 1983 lol
pH strips are very cheap and easy to find from the pool maintenance section of just about any store that has a pool section. It could be used to figure out what has leaked and where. Batteries are acidic while cap juice from the types of caps you'll typically find in vintage PCs will be alkaline. If nothing else, it could help you choose what kind of neutralizing agent to use on that sticky dust.
I have some pH strips. Too bad I didn't think to check!
"I'm just going to use the dremel here..." (Vietnam flashback meme but it's 8-Bit Guy)
Bruh... I can't even use paperclips anymore.
If you have a large area to clean (of flux), especially when there are many components in the way, you might want to consider putting the board in a plastic bag and fill it with IPA to thoroughly soak the board and leave it for a while for the IPA to dissolve the flux, and then of course wash the board afterwards.
"I almost forgot the speaker"
LMAO in my case it would be "ooops I "accidentally" put the speaker in the trash"
lol. I'll make sure to get some AdLib sound in it very soon :)
@@Epictronics1 I do have fond memories of Quadralien, but I found out a few years ago there was an amiga version. Better graphics AND the music is killer. It's the same songs, but WAY WAY better.
probably the only time I didn't hate the PC speaker.
Applying new solder to corroded pins is definitely necessary, not optional imo.
I use hot air at 150 degrees c or so and the desoldering gun. That way you don't need to heat up the whole board and the desoldering iron heats back up quicker as well after each suction.
For very stubborn ones I also use low melt solder.
I'll try with the rework station, thanks
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
yeah, I love my chipquick, I use it all the time for large chips. Never thought to try it on stubborn tantalums though. Thanks
if you have a 3d printer you could put it on the bed to keep it at like 100 degrees or so. lol
Impressive skills and knowledge and a nice sense of humour too! Subscribed!
Thank you :)
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.
Yeah, I know it requires some magic to surpass 640k but I haven't done my reading on the topic yet. Perhaps this card can't do it at all.
@@Epictronics1 Is there a model number - can it do EMS?
@@matthewday7565 Unfortunately, I don't know. I will dig deeper into this when this IBM is back on the bench
"Maybe I should have used a dremel. Maybe some other day." Lmfao
Nice IBM 5160 and a nice repair. Great video. Greetings from Steven from the Netherlands
Thank you
Very satisfying!
The board your reworking is from IBM, and most likely is a multi-layered traces, connected by via's very delicate to remove components from without damaging the via's.
I wish you used some Ph strips on that juice. I figured it was oil used to keep the steel from rusting...
Yeah, I wish I thought of that. I actually have some PH strips lying around. It would have been so easy to do
it's pH. Seeing it as Ph and PH, as someone who used to be a (terrible) chemist, that's like nails on a chalkboard.
@@adampope5107 LOL my phone did that. What bothers me more is people putting the dollar sign after the amount like this: 10$.
@@tigheklory yeah that's weird to see too.
There is a seller i thought for the floppy part - i dont recall the search terms but it replaces the plastic pins with a brass bar.
bar is on the way :)
Not surprised it didn't like the RAM card when the RAM had already been filled on the board
You can use cut brass rod segments to fix the drive doors.
It's already on the way :)
FYI, that chip on the expansion card is a "microprocessor real time clock". So this bugger requires the battery.
That could be very useful to know when I do more tests, thanks
@@Epictronics1 I'm not sure that memory board is worth fixing though as it's pretty janky and you can buy a modern 1MB XT RAM expansion card for just a few dollars. I'm pretty sure there is an open source version available. Just remember any extra RAM will be EMS and only used by software that uses EMS memory. There's no UMB on an XT. For the most free RAM update to DOS5 or use something old like DOS3.3. DOS 6.2 won't give you anything extra and leaves less base memory free.
AMD Story.... I mean, I've probably heard it countless times... But
I'll get the Popcorn
Could you add even a little benchmark if you overclock these repaired machines? Because many of us like bar graphs like original vs. overclocked/tuned. Otherwise thank you about nice video again, can't imagine how much time it actually took to tinker all those tiny traces. Yikes! My 1st PC was 8088/8MHz about 36 years ago, still slower than your overclocked 5160. But I had 640k and massive 30MB HDD 😍
This 5160 runs at roughly 7.5MHz with this crystal. Your first machine was slightly faster:) I ran out of time, unfortunately. I like to end my videos with a benchmark when I can
I like the white vinegar method for the battery damage :)
37:40 Just a FYI, there are a some uncommon 82S129 bi-polar PROMs on there (256 bytes x4-bit each). If they go bad that card will be permanently dead with no fix possible. You may want to make an effort to dump them. PROMs are not supported by el-cheapo eprom programmers but if you have a proper eprom programmer or a Retro Chip Tester Pro it can dump them. They can also be wired up as a 2716 using only 4 data pins and 8 address pins and then read it and chop it to a 256 byte file.
If you wanted to identity that oily residue as battery acid maybe try one of those pH test strips. Great work!
Thanks! I wish I thought of this before I cleaned it. I have some pH strips laying around here :/
The battery juice is a base, alkaline. That's why the weak acetic acid in vinegar neutralizes it.
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
2 disk drives so you can have os in one drive and whatever program in the other. Many computers in the late 70s early 80s even just came with one drive which must have been a chore.
@@initial_kd yep it was ms dos in first 5.25 and the second drive for printable documents... 1995 as far
I think, if you only pre-heat the board when working on GND pins, you don't have to re-heat it so often.
You can always install and run Windows 3.0 in Real Mode, it even fits 10MB harddrive space. That is what you can do.
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.
Maybe someone sprayed oil onto the fan barrings to make it less loud?
Hi, I really like your videos :-) I'm too in the process of upgrading a 5160, did the 640k hack, swapped CPU for a NEC v20 and looking to add a Skinny Sprint. Uploaded the gerber files to PCBWay and wanted to quickly confirm with you that these indeed are 4 layer?
Thanks. Yes, they are four layer boards
@@Epictronics1 Great, thanks! As I have to order at least five, do you mind if I put the spares on ebay at a nomial cost? Will of course give you credit ;-)
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?
Yes, I use chipquick for large components. I only use white vinegar to neutralize battery juice
. . . These equipments cost $6,000, so pulled 6 missing screws gets most of the item's value back . . .
This PC isn't rare enough to use a Dremel on its security screws.
😆
7:15 - greetings to the 8-gun-guy and all available paper clips
Alright, settle down. Nobody ever heard of, or cared about those PCs before he took them home. If he hadn't, they would've been chucked into the skip. Sloppy as it may have been, a few scratches on the case is a better fate than what they had in store for them.
@@nickwallette6201 Watch the video again; he had that PC on loan. There weren't a few scratches on the case; he cut into the PSU case with a Dremel because he had to release a video that month. Those PCs were never going to be thrown out; they were going to collectors who care about vintage IBM hardware.
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.
I've heard of this mod. Apparently it's quite complicated. If there is enough info on how to make it, we'll try it out
I really must question when the Varta class action is.
It's an electrochemical component that was purchased FORTY YEARS AGO for, most likely, a 5 to 10 year life span. It's behaving about how it was supposed to behave. They weren't designed or even imagined to last this long. It's not Varta's fault that materials fail when used 4x to 8x their service life. If one needed that longevity, one would be expected to service their equipment properly. Blame the owner for failing to do that.
I am a little confused. @3:03, you mentioned three tantalums that are going to blow. I know that electrolytics will eventually die (sooner if of lower quality), but I have never seen a failed tantalum. Then again, I am on the design side, but are dead tantalum caps really an issue?
Yes, old tantalum caps, such as in these machines, of that era, go bad A LOT. They tend to fail shorted. If that happens in storage, generally the power supply will simply not start (in the case of IBM PC products, for example). If it happens after the power-up, they like to blow smoke and fire.
Do you have an ultrasonic cleaner?
I think so, he said something about "after I opened the lid" after he cleaned the mainboard :)
Not yet. I just wash my boards with warm soapy water
Adrian from ADB did a video on repairing those floppy drive doors and 3d printed parts to fix them:
ruclips.net/video/KGuJ185u5f0/видео.html
Thanks for the reminder, I rewatched the video. I disassembled the drive. The part that Adrian had to print only has a small crack in my drive. I'll order a rod and glue the cracked piece. I'll try to include it in the next IBM 515x video
I'm older than that computer
You're also older than my current PC.
I'm older than you
🍪
PLS PLS HELP ME to repair my XT boards (x2)
Can you go beyond 640k of RAM??
I have not done the reading yet, but supposedly there is a trick to make it work
@@Epictronics1 Note anything more than 640K would be above 1MB and would be EMS memory requiring a driver and supporting software that uses EMS. There is no possibility of creating upper memory (UMB) or using himem.sys etc and it is not supported on an XT.
@@g4z-kb7ct UMBs work fine on XT-class systems.
7:19 "Maybe I should use a dremel"... That burn toward the 8-Bit Guy xD . I see that retro computer community still did not forgive him for butchering that prototype executive IBM :D. And this was over 3 years ago (on another hand he still did not unlock the comments under that video)
There were a bunch of extra Executive power supplies at Computer Reset. Also, compared to other prototypes and rarities found at Computer Reset, the Executive PC was not even that amazing. The test bench in the warehouse smoked out much rarer stuff.
@@psergiu Doesn't matter. He was demonstrating how to be a hack/butcher.
@@billlewis9740 How ? It is standard practice to turn on power supplies like that. I know I was doing it from before youtube ever existed. I would have done exactly the same thing as he did. I know David and he's way more mindful of preserving valuable hardware that I'll ever be. Also, a local community member fixed that particular smoked power supply - so literally, nothing was lost.
@@psergiu Standard practice for people who then are surprised when things blow up.
Honestly I don't know why I bother.
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.
damage is from excessive heat not the tip type or brand of desoldering tool lol
You forgot the disclaimer when opening a power supply…
Here you go:
If you open a power supply or CRT monitor, _you will immediately die._ Do not attempt to service without copious life insurance. You're a goner, but your beneficiaries will thank you.
@@nickwallette6201 Well done Nick, but if I die, I’m taking you with me…☺️✌🏿
@@thabophadi Eh, I was headed there anyway.
lol
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.
yeah that was known 40 years ago, where have you been?