486 VLB board found at Computer Reset. Power rail and keyboard circuit repair
Вставка
- Опубліковано 7 лют 2025
- Severely battery damaged Shuttle HOT-419 R1 Motherboard.
The remaining repair here: • Extreme 486 VLB board ...
PCB Prototype the Easy Way. Full feature custom PCB prototype service. www.pcbway.com/
--------------------------------------------------------------------------------------
Support me on patreon.com/Epictronics
Join me on Twitter: / epictronics1
--------------------------------------------------------------------------------------
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
InfiRay P2 Pro Thermal Camera
PCBs from PCBWay.com :)
--------------------------------------------------------------------------------------
patreon.com/Epictronics
Join me on Twitter: / epictronics1
Music by Karl Casey @ White Bat Audio - Наука та технологія
Support me on patreon.com/Epictronics
Join me on Twitter: twitter.com/epictronics1
I love watching these kinds of repairs. Boards most people wouldn't look twice at and even the most hardcore enthusiasts wouldn't even try to repair. You never see this stuff, so it's wonderful that you're doing it.
No board left behind :)
Amazing video and a real inspiration ❤
Thanks Phil :)
"Why do I take on projects like this?" Thats a fitting title. 🤣
Haha, I may use that title someday!
When you said the Dremel was too bulky, I immediately thought about the flex shaft, but a second later you came up with it lol. Great work. I have a 386 in similar, but not as bad condition, my old board, which I hope to restore someday, but I'm far from having all the tools, and most importantly all the skills and knowledge necessary for that enterprise and I'm almost about to give up on the little thing. CPU and math co-processor are intact, though. Keep up with the great job!
Thanks :) In that case, I would just add a small amount of 25% white vinegar for NO MORE than five minutes on all the green areas and wash the board in warm soapy water. That will neutralize the battery juice and give you many more years to prepare for the repair. Good luck with the project
I am amazed and staggard at this repair. Real and honest repair and impossible to most . I see so much fake rubbish and then I fined this draw dropping repair. I am in awe.
Thanks
Your "fuse" is just a zero ohm jumper, and your inductors are just jumpers with ferrite beads. You can usually just pull the wires out of the inductors and put new wires through them. Worst case scenario, just replace them with jumpers, they're just there to cut down on RFI.
Thanks, apparently cheeped out on the fuse :/
thank you for the video. love seeing old boards being resurrected from the grave.
Thanks :)
I admire your patience. That board needs a hell of a lot of work to get it working. I look forward to part 2.
Ah, beautiful! I have some computer reset 486 boards on my repair bench as well, so thanks for the information!
Good luck!
This was hands down one of my favorite motherboards in the day. I think there may have even of been a PCI variant.
Thanks again for a great project. I can proudly say I bought a 486 mainboard on eBay with several issues. Thanks to your videos I feel confident enough to give it a try! 💪
Good luck!
This is amazingly tedious project to do, but a great video for us that get jump cuts! I admire your dedication (or insanity) in taking this on. Thanks!
Thanks :)
This brought back a lot of memories! My first 32-bit system was based on an Opti 495-SLC VLB motherboard with a 386DX2 processor (soldered directly onto the board iirc) :)
I have this mainboard but with the ISA sockets in white, I think those boards were famous for the possibility of having fake cache.
Yep, the grinding pen is in my wish list for this kind of brain-surgery difficulty level. Thanks for the video!
It's a great tool for large and thick traces. Looking forward to comparing it to rubber polishing tips
Great video! I think I will now be able to quickly recognise corrosion damage that is just too great, and would just be a project that would break my heart 😢
Fascinating work of patience. Can't wait for the next part :)
I trashed two 486 boards in the past because of battery leakage, and seeing you work I think I could have repaired them.
🎵Pins to the left of me, through-holes to my right, here I am (stuck in the middle like glue) 🎵
It's like an episode of Csi. Just needs a cameo of Caruso. Love the tracing of faults to get to bottom the malfunctions. It's informative and entertaining at the same time. Looking forward to the next episode
Thanks :)
Thrilled to see more work being done on CR boards!
This board is tough, but I'll do my best!
I have been working on a 386 board this week and got the same post code error 13,12. I figured out that I was using an intermittently working video card. I replaced that and I can now get to a boot screen but now I have a "Keyboard Interface Error". So I'm enjoying watching you work on this in hopes I can figure out my own problem.
That might be very useful info. I'll try with a few other graphics cards. Thanks for sharing
I'm sure you know it but just in case: try spraying deoxit over chips that are really stuck in sockets but you still want to get ejected. Deoxit typically acts as a good lubricant allowing for a way smoother chips desocketing so you'll end up with more sockets intact and chips remaining with all legs attached.
I'll give that a try, thanks
Found your channel and love it. You don’t give up.
Thanks
Notice that having removed the keyboard connector you can see the holes for a PS2 style socket. The middle pins of the power connector are ground, and the ground plane will act as a big heat sink, which always makes desoldering of these type of pins very difficult.
Wow, I brought back a n64 rumble pack from the dead that I left batteries in around 2004ish a couple of weeks ago. I only had to clean up a couple of traces to get it working again though. Very impressive from what I've watched so far.
Thanks. It's on the bench right now. I have repaired 14 traces so far, but not done yet :o
Looking forward to part 2!
I liked that IBM PC Jr. you were showing at the very beginning of the video, with all the signatures on it. That was my first computer and iirc, I could never get it to do anything unless I put a cartridge in and it would sorta reboot and run whatever was on the cartridge. Otherwise it would give me a prompt and just say syntax error no-matter what I tried to type in...
Interesting problem, would have been fun to repair :) I have made several videos about that PCjr. I just ordered some parts for yet another PCjr video.
Nice job and a great board to work on. Nice content. Greetings from Steven from the Netherlands
Thanks!
You can use an UV light to find out were the destroyed traces went. Use protective glasses while doing it, as the light will reflect on the board.
I'll give that a try. Thanks
You can just try different coloured light. UV is ok but you might get similar results w or green. think ALS and CSI :-)@@Epictronics1
@@danielflakelar8193 Mobo CSI lol
Been there, it's a matter of patience. Family pack at winter clearance with refills.
Can't wait to watch part 2 and maybe 3.
To remove the corrosion in the traces, you can also use a scalpel. I learned that 3 years ago watching Bruce Wayne (from Branchus Creations) repairing vintage Macs. He has a few tutorial videos on his channel.
UV curing solder mask (another use for the uv lamp/light), is also nice to have, to seal the repairs. Nail polish can be used as well, but will be removed if you need to clean the area with isopropyl alcohol.
I have found 400-600 grit sandpaper with light passing works pretty good, basically what the tips do. I have those tips too and they work for sure but need good handling. Sand paper works when lazy
Thanks, perhaps I should practice on a scrap board before I take on those thin traces
Damn it, missed the premiere again. At least I can relax watching someone else repair after failing to repair a 486 ThinkPad 😁
486 ThinkPads are tits. I hope you can get it fixed!
i scored a 486 VLB Asus board couple years back. perfect condition.
It could be epic if you and NecroWare could elaborate on a project...
love his videos
I have a similar one, which also has some battery damage, but not as bad as this one. I took one of its ISA slots for something else. Sadly I don't have a 486 to install on it, but one day I'll have and I'll probably fix it. Thank you for this video (and all the other videos as well).
Good luck with the project
No board left behind 😊
Hey, that's a great title too :)
30:00 it's a simple ferrite bead so it's fine as-is. Technically you could replace it with a solid wire and it will still work.
Great, thanks
The very slow POST codes seems to have started when you plugged in the keyboard? It wasn't FAST before but got positively glacial after you plugged one in. Which kind of hints that you might have issues in that part of the board - I would suggest checking if the POST codes are still as slow if you run without a keyboard plugged in. It might give you one thing to tug at, but I think there's likely still multiple errors left to find.
I decided to give that a try right away. Unfortunately, It's as slow without the kb. Something else is slowing this board down
I used to love these boards, built many a computer with them
Oh yeah, Epictronics is getting an abrasive eraser tool! He's gonna be unstoppable now!
haha. Watch out, all the VARTA-damaged boards out there! I'm coming to get you 😆
Sweet mother of dingus. This is a god tier level repair. Other UA-camrs should look upon this video and weep.
lol, thanks :)
So it turns out I was quite drunk when I made this comment. I still stand by it, but just to give it some context haha.@@Epictronics1
@@cromulence 🤣
*TIP #2*
when you have many traces that need to be repaired start from one side of the many tracks close to each other,
Once the first trace is repaired immediately coat it, and then do the next one next to it followed by coating that
one as well, so on and so forth..
Enjoyed this one! Look forward to the next installment! :)
Thanks :)
resisters with single black stripe are 0 ohm jumpers (basically a fancy looking Jumper wire)
I use those green bits by hand. They work totally fine without the dremel :) I do recommend them - though you're going to be removing ALL the solder mask, but I think this is what this poor board needs :)
I also have an MSI board with an implosion on top, not sure I want to spend time on it!
I had to try that right away. It worked! Although very slowly. Yeah, this board is going to need lots of cleaning with the Dremel lol. It's on the bench now btw, fingers crossed!
FYI: a single black band on a resistor means it's a Zero Ohm Link. In this case, it might act as a Fuse as well.
Yeah, I just assumed it was a fuse because that's what the silkscreen showed. Apparently, they cheaped out
@@Epictronics1 : With the magnification, it's not easy to guess, but it does look like a 1/4W resistor. And depending on the voltage supplied, it'll get really hot somewhere between 50 and 100 mA and go up in smoke somewhere beyond 100mA.
Using a resistor as fuse is rather common. Though in my personal experience, they usually use such "fusable" resistors primarily for limiting current, and secondarily as fuse.
But then again... I could be wrong.
@@bikkiikun Ok, so some level of protection then. I guess the risk of a short in a kb isn't that big
You might try using a pencil eraser as an abrasive cleaner for PCBs. You'd be surprised how well that can work. It's faster than a fiberglass pen in situations like this one.
I'll give that a try, thanks
Outstanding work, so far! There are a couple of things that I noticed:
1) There seem to be TH-pads for a PS/2 keyboard connector. Did you see the U-shaped grid with 6 holes in that area? You repaired a trace via one of those pads.
2) Could the board be running slow because the Turbo function is setting the CPU speed to 4.77 MHz?
Oh, the Turbo, I should have thought of that. I only did a super quick test after I made the video to confirm that the board was running slower than the expected 33MHz. We'll do a proper test with the scope and check the Turbo jumper before we continue. Thanks!
Such a shame that computer reset is all gone now. I had always planned to go but now that I finally have the time it's shut down for good.
I find a brass suede brush with isopropyl works well for removing corrosion.
Give it a go.
I use a scratchy brass pen on corroded chip legs, works great.
Do you have a way to check the system clock speed? It seems very slow, because everything happens at a really slow pace and the beeps have a much lower frequency than normal. Maybe this also causes issues with DRAM refresh.
Oh, I should have thought of that! That would explain the ten seconds between code 10 and 11. I'll check with the scope, thanks!
Ooh! You’ve just fixed me up with my daily dose of masochism. Thanks!! :D
32:32 Roman, you should definitely try to put some varnish on those installed leads. It’ll look much neater! :)
Thanks (again) for your awesome content!
Thanks :) I'm considering replacing them with copper tape actually. Not really happy with those thick wires underneath the diodes
Board is held together with hopes and dreams.
Jeez... I appreciate your effort
Thanks, I have made some progress this week. New vid tomorrow
I use one of those dremel extensions on a black and decker unit. dremels are overpriced but they have good mounting mechanisms, a chuck instead of a collet that most have. but you can find a lot of other compatible tools to the dremel chucks.
I ended up getting the Dremel 3000. I'm super happy with it. It cleaned up the board perfectly
Wow that board is in very bad condition. Let's see how it goes, to me it is more work than it is worth, but this is why you are making the video and I a watching you! Thank you.
lol. It's all about the challenge
Wow man, only Epictronics !😀
:)
We need to get you a large ultrasonic cleaner
I had this exact motherboard I put an overdrive in it but I think it may have needed a bios update iirc bought a p-200 mmx to replace
26:50 there are two traces that go under the screw hole on the pcb. I might be wrong but it seems you only fixed one.
You're right. I missed that one. I did see it in the final edit though. It's going to a via very close to the battery. It definitely needs to be checked for continuity.
I would love to see that board in a RAT ROD mad max like case. Use boiled linseed oil nullify the rust and keep the patina. Use an old rusty screw driver for a case brace. Make it look like someone built it out of scraps in a post apocalyptic future. Not steam punk because that has been done too many times.
You may try experimenting with melamine sponges, they're mildly abrasive, so perhaps small chunks glued to toothpicks or something so you dont take too much off at once.
That could work, I may give it a try
That board was quite nasty, which makes it interesting for a video. An alternative to a Dremel tool, might be plain old sand paper.
I may give that a try too, thanks
I had that board! (well, not that exact board, but that board)
Would be more interesting to get a new PCB done for all the chips
I had a Packard Bell 486 motherboard that I sent for recycling because of the battery. Now I wish I didn't.
I have a working 486 VLB system - with VLB video and I/O cards, otherwise why bother? - that I use to create floppy disks for my Otrona Attache. It never had any battery corrosion because it used the Tadiran little "bricks" connected by wires.
Great work!
Thanks!
gigapauls of flux
use up the entire stock of amtec that louis has
It seems you do like a challenge! 😉
I am betting that zero ohm resistor is just that, zero ohm resistor. One black band. Just a thought.
The thought never occurred to me. The silkscreen has a fuse symbol. I just assumed it was a fuse
Yup, "resistors" with a single black band are zero ohm jumpers. They apparently cheeped out and replaced the fuse the engineers wanted there with a jumper. It would have protected the motherboard from a keyboard short. Not a particularly common fault.
Really bad corrosion, have some boards in such shape and I am not sure do I want to start repair at all.
You should, it's fun ;)
No, its frustrating and not worth the effort. I wouldn't attempt to repair a board this badly damaged. too far gone.
probably shouldn't use flux when using a desoldering gun because it can really gunk up the filter.
Yeah, It's a pain to clean it after a project like this
somehow my MB cpu pins some damaged idk how never taken apart As time goes by i,m learning how to fix this issue 3 ram slots stopped working
i straighten a few pins and got 1 ram slot A working when i do i,ll check the others under the led magnifier If no go buy a cpu slot $6,00 and get it resoldered on M/board
Removed liking the battery to vinegar.
Varta must be the most cursed company of all time.
*TIP*
Before desoldering put some flux down, as it cleans as it is heated
But more importantly assists for a quick desoldering..
Ewps 🤭never mind I see you discovered the flux trick.. APU👁👍
It's an amibios and it's all versions
This thing almost needs a vinegar bath
varta is the bane of retro
if you have a varta brand cell on a device that is old, yeet that shit
doesn't matter if it is still intact
a CR2032 or a remote AA pack is far more useful
if you wish for the rechargeable options you can get LIR2032 cells or even just whop in an 18650
Why do you not use a really fine 1200 grit or 500 grit sandpaper to remove the soldermask and expose the traces? I mean what is broken is broken anyway, and what will be gone will be no good anyway, so I have some good experience with a fine sand paper, it is smoother and has more area and more convenient over the glass fiber pen and the rotation tool grinding pen thingy you use. I don't know, maybe there is a reason, but I would just sand it off, make it shiney again and then you see the problems better.
I may thy that on some future project
23:20 - Impressive, I'd probably be all over the place.
At 31:00, why did you not used a PS/2 connector for keyboard? You have there the footprint for it.
The thought only occurred to me days after I made the video. I should have used a PS/2 connector.
I have a Shuttle HOT-419, but unfortunately it’s a different revision. Assuming you get this board up and running, I would be curious to know if your board enables both caches… my board, or the BIOS for it more likely, is always disabling the CPU’s L1 cache no matter how it’s set.
Interesting. I had that exact issue with another MB. It didn't recognize more than 8k L1. When I installed a DX4, it would shut all cache off. Did you try all the different versions of the bios that are available on the retro web?
@@Epictronics1 Not yet, but I will at some point, as I’m going to make a video about the board’s odd behavior.
At 26:01 are you sure the bottom trace is connected to the via? I see a break.
You're right. I missed that one. I did see it in the final edit though. It definitely needs to be checked for continuity.
Good topic- very good video and workflow but i have an ssssss issue in audio 🐍
The CRT?
Yessss - it was the crt not ssssyncing on green ;) , thanksss@@Epictronics1
Cant you damage it further by powering it up in such a corroded state?
I don't think the corrosion is conductive
Of course not, I'm not stupid. What I thought was that the smaller components like capacitors giving incorrect voltage to the cpu and other chips therefore damaging it furhter?@@Epictronics1
@@kalsvtg5169 Maybe it's possible. Hard to tell
I gotta ask. How long did it take to get this far in the repair?
I deliberately avoid counting the hours I put on a project like this :)
Ремонт еще не закончен, продолжение будет или решил бросить?
I'm working on the board, as I write this
order some ear plugs with that dremel. the extention gets very squecky ^^
Oh, that could be a problem when recording video. I hope it's not too bad
Necroware approves 🙃
Hopefully Mr Dremel helps! 😉
Looking forward to trying out those rubber polishing tips!
I'm sad I never got to go :(
Be careful all the settings on a dremel are fast
speed 5/10 seems to be right for the job
The first thing I'd do (besides say NOPE) is remove the chips from sockets and then just dunk the whole thing in a container filled with vinegar and let it sit for 2 days.
The vinegar would eat up all the metal on the entire board lol
@@Epictronics1 at least it wouldn't be corroded anymore. lol
Зря ты маску дремелем снимал, надо было химически ее снять. Средства для прочистки труб на крепкой щелочи хорошо подходят, это более щадящий способ, можно использовать локально.
Sounds interesting. How can I find this solvent?
@@Epictronics1в любом хозяйственном магазине. Популярные бренды: BAGI, EFFECT, GRASS, LAIMA, SANFOR, SANITERRA, SYNERGETIC, TIRET
@@Epictronics1я для тебя снял шортс (короткий ролик) до какого состояния обрабатывается печатная плата, полностью удалена паяльная маска и шелкография.
@@mask-u5v Sorry, Google Translate didn't make much sense of that sentence. What is the brand of the product you use?
@@Epictronics1у нас он называется "Крот" самое дешевое средство. Спроси в магазине консультанты подскажут. У нас нет американских брендов или они завозятся под другими названиями. Средства для прочистки труб все выпускаются на основе щелочи, просто есть более концентрированные и есть менее концентрированные. Тебе надо выбрать более концентрированное средство.
У тебя хорошо работает переводчик?
У меня нормально, все от тебя читаю без проблем.
У тебя сейчас ночь наверно, не хочу тебя напрягать, пиши когда тебе будет удобно🖐️
you are crazy - in a good way. That thing is so busted haha
It's not smart to power-up the board with that green corrosion.
I don't think the corrosion is conductive. I may be wrong
@@Epictronics1 Well, technically giving it electricity makes it worse by speeding up the corrosion process, or so I read. But in this case it doesn't matter as you were going to clean it very soon after anyway.