Mystery Box: Testing, fixing and overclocking motherboards

[@EdwinNoorlander]

Hi Adrian, I worked for a Taiwan company in 1990/94. Sunnytech, this company made this motherboard you have here. I remember most motherboards had buffer problems.

[@thegarmac]

Please continue the treasure hunt. Feels like I’m back in time at a used parts computer store digging through their dumpster and finding treasures

[@johnpawlicki1184]

My recollection was that IBM downgraded the AT to 6 MHz before selling the first units then offered an upgrade to 8 MHz. Worked on one for many years. Love these videos.

[@parrottm76262]

Love overclocking sessions! I used to spend hours squeezing every drop of performance out of my old systems. Endless upgrades until something shiny and new caused me to upgrade.

[@myownalias]

Personally, I love these longer-form videos, I'd love to see parts 2, and 3, and 4, and 5...

[@petefish9401]

More Adrian, this is the sort of thing about your channel I love, random tinkering and testing. Bring on the rest of the boxes mystery contents please.

[@cybercat1531]

One tip for you when dealing with dead boards that have QFP/PQFP chips on them: Inspect the pins with your microscope and tweezers, they like to come off the board either due to degrading solder or flexing of the board and can easily cause a board to appear dead. It's by far the most common fault I encounter while fixing old boards that have no post code activity. And as an aside if you see no post code activity at all on the card it is not the ram that has a problem. Ram init occurs relatively late after rom is executing already, so if there is no acitivity you either have a bad rom, or more commonly bad Voltage rails or lifted/degraded chip contact pads.

[@lee3521]

Good job "debugging" that second board! Things were so much more simple back in the 286 / 386 days. Great video!

[@kpanic23]

He removed the tic that marked it as good, no wonder it doesn't work any more xD

[@GabrielZ666]

Hi Adrian! Some motherboards may not work at all without a battery. You should try using a battery pack on the external battery pins!

[@danfrench5221]

facts

[@BigDaddy_MRI]

We use these wireless RS-232 devices with our RF room testers. One goes on the controller unit, and the other on the transmitter inside the RF room. We set up the transmitter inside the RF room and the sweep antenna on the controller outside the RF room. The two devices allow a full RS-232 at around 2 GHz, and the RF room is tested at 100 MHz and one of 2 other frequencies. The 2 GHz used in the transceivers will work fine, because the RF room is tuned for MRI frequencies and doesn’t filter 2 GHz. Obviously, I’m talking about MRI exam rooms which are integrity tested at 100 MHz and 127 or 64 MHz. So those wireless RS-232 transceivers are used with our RF room test units. The dip switches are for matching the two transceivers together, like addressing.

[@patprop74]

Nice overclocking, love how excited you get from a whopping 9mhz lol I do enjoy full box treasure hunt and exploration.

[@tracyscott3261]

YES! Great video. Thank you.

[@mickkeeble3079]

Yes, way back in 1984 I overclocked an IBM PC/AT to 8 Mhz! I was an IT techie working for an International Oil company based in London England. We worked closely with IBM and tested and verified all of the early IBM Personal Computers and associated Hardware and Software products for use in our company. I remember getting 4 of the very first PC/ATs in the country for testing. Based on Technical journal articles and chat on BBS's that discussed early overclocking the AT to 8 Mhz and being an electronics enthusiast, I purchased a couple of 16Mhz crystals. I remember they had wire legs so I had to solder proper sized legs to them for the on board sockets. But yes I successfully ran two of the machines at 8 Mhz with no problems at all, apart from running noticeably hotter. I received many visits from other techies, from within the company and even from IBM UK who were based just along the river, to see benchmark utilities and other programs running at "breakneck" speed on my souped-up AT. Yes we were all geeks even back then!!

[@mikeosx2009]

We want more, don’t do the rest of the box without us!

[@rfmerrill]

15:09 Gahh!! more flux!! Flux will stop you from leaving solder blobs everywhere! They're annoying because they're just sticky enough to not come off the solder mask easily but I don't feel like you can just leave them there. Also I think if you warm the board a little it'll stop the solder from solidifying on contact quite so easily. 15:34 Pretty good job! I do this kind of work a lot. What I would do is solder one side, cut, then hold with tweezers and solder the other side. With light wire like that you end up with what you saw quite often which is that when you try to solder the second side you end up undoing the first joint. It can be hard to actually hold wire with tweezers sometimes so what I do is flip the tweezers around and pin the wire down with the butt end (or just hold it down with the side of the tweezers). 15:45 I would always add more flux before reflowing a joint like that. It came out looking okay, but when you melt solder with no flux around it *really* wants to oxidize. 15:52 Looks like you did just fine with the snippers, but a tip for fine wire work like this: #10 x-acto or scalpel blade. You can cut right through the wire with the blade but you might end up gouging the board surface--what you can do instead is push the blade into the wire a little and then use the blade to hold the wire in place while you wiggle it to break it off. 18:46 I usually prefer to use some a sewing needle to do scraping like this but if you don't care about your tweezers that's also fine. 19:38 Copper takes a long time to turn green purely from exposure to air. Oxidation from air also tends to be self-limiting, not penetrating too deep from the surface. Still a good idea with the lacquer though.

[@wojiaobill]

Why does the 286 motherboard take so long to finish its tea? Because it only takes SIPs.

[@johnpetruna8888]

[womp womp]

[@mattparker9726]

hahahaha I'm stealing that.

[@clintthompson4100]

I love it.

[@Taisen_Des]

Mr. Microscope 🔬 reveals itself as the new sensation of the channel. 👍 😉

[@ultrametric9317]

IBM equipment - bulletproof! THE best. I remember a PS/2 model 55 I ran across in my consulting days that printed invoices on a dot matrix Proprinter. It has been running flat out for 11 straight years! No power management, no time out, just 24/7 operation all the time, every day, for 11 straight years.

[@badscrew4023]

The 386 motherboards like this one were used in slim form factor desktop PCs made by many off brand manufacturers. I had one and loved it! It was so much smaller then usual PCs at the time

[@MartinWolves]

The microscope footage is a great addition!

[@rodhester2166]

awesome video. really enjoy the trouble shooting process and a mixed box of unknown parts.

[@HAGSLAB]

Always a nice surprise when I reload KZbin and see a freshly released video!

[@AlexCreemers]

Specially when you are done with work.

[@joelh5847]

I had no idea you were in Portland. I'm outside of Astoria. You're my current favorite KZbinr. Such an interesting channel. Back when I was a kid my brother and i got like garage sale computers and tinkered with them. In retrospect, I wish I had those old computers now. Lots of 286, 386, and 486 computers. Keep it up man!

[@no1leader135]

I want more! I want more of this kind of videos. I love it.

[@megaglowz8540]

Almost an hour!!! Ahhhhhh Great video!!! Got my recliner, lunch, and some basement!!

[@rager1969]

That AT overclock was fun. Good job!

[@darkwind9000]

Those overclocks are fantastic!

[@chadhartsees]

They LOVED them some jumpers back in the day!

[@chadhartsees]

I'm loving the 'microscope cam' (for lack of a better word).

[@hugosimoes5119]

Amazing job. More of these videos please.

[@andrewsutton6640]

22:09, the Firefly Serial to Bluetooth resembles a Serial to Bluetooth device stenographers use to connect their steno machines wirelessly to their computers.

[@Petertronic]

A fun tour of mystery PC boards, loved it. Those off-brand motherboards were everywhere in the UK too in the 90's.

[@AntonyTCurtis]

The early IBM AT BIOS was okay with running at 8MHz. The later versions had checks which prevented booting if it was running too fast.

[@VidaDigital]

Also the 386 CPUs have a chipset between the ISA bus and the CPU, which the 286 CPUs didn't have. That chipset could probably negotiate or detect the XTIDE better, whereas the 286 might have been just talking too fast to the XTIDE directly.

[@coctailrob]

I have the 407 version of this scope. It can do simultaneous display on the internal screen and HDMI. I also solved the working space issue by mounting the base 180 degrees so it points backwards, flipped the power connection to the lamps around, and clamped the base towards the back at around 2 inches off the bench. Works great but is now more of a semi permanent install. Also protected the plastics exposed at the edge with some Aluminium tape.

[@FightingForceSoulless]

I love how you're sooooooo happy swapping the crystals to get that extra overclocking speeeeeeeeed, honestly, made my day :)

[@adriansdigitalbasement]

There is a followup to this on my second channel as well.

[@FightingForceSoulless]

@@adriansdigitalbasement Just finished watching it, I hope you can get it stable, because apart from that, it's an outstanding effort. I really like the idea of having an arduino crystal where you can change the frequency to anything you want.

[@stephenoflaherty5656]

Best video for a while. Random junk could be new series of content. Love idea of overlooked stuff getting attention it shouldn't really be getting. Thumbs up from me

[@gamercat1975]

I love your enthusiasm, it reminds me the little pleasures in life.

[@frankowalker4662]

Can't wait to see what else is in the box. :)

[@tonnywessels2668]

Looking forward to the next video. These are the best video's.

[@BertGrink]

Yes please, I want MOAR of this

[@stevesstuff1450]

Are we interested in seeing these types of videos? Speaking just for myself; Of Course!! This type of stuff is why I subscribed....and I'm sure I'm not alone in this.... Seeing you revive these old boards and computers is why we're here! Of course, your charming personality, and detailed explanations as to why and how you do the things are all a big part of it, so yeah... please, lets see the other items in the box...don't tease!! :-D You are great, do your thing, and thank you for doing these fascinating and entertaining videos... :-)

[@ESDI80]

I remember reading in a computer repair / upgrade book that people did over clock the 5170 but changing out the crystal like you did. I also remember reading that IBM updated the BIOS to not support over clocking in later BIOS revisions and I'm wondering if this is why your XT/IDE is failing. IBM had mentioned that the type 1 motherboard can't handle proper timings higher than 6 MHz.

[@stevec00ps]

Nice video, looking forward to the next part(s)! Maybe move the little monitor to the right hand side so it's nearer the camera? And recheck that trace on the 486 board - I think it's still broken further along to the left of the repair! Look at 17:40

[@TnFlightMedic]

Really enjoying the microscope! Great addition to the video!

[@rarbiart]

I could watch these debugging videos for hours

[@RetroAnachronist]

Ok guys, this video better be popular. Enjoyed it!

[@braedan51]

Good work on the debugging. :)

[@jimtrussler9232]

Enjoyed these troubleshooting videos. Always informative and entertaining.

[@devttyUSB0]

Kind of interesting what gems are hidden in that box!

[@rogersandberg4823]

In 1986 I used to run my IBM PC/AT at 10MHz with a 20MHz crystal. For some reason I had to swap the floppy drive for a different brand to get it working at 10MHz. At one point I had 12.5 MB memory in it for testing purposes.

[@Robert-mt9jw]

The DX50 you repaired the trace, then broke it again with your tweezers @17.39

[@EvilTurkeySlices]

Didn’t notice that the first time, but watching it again I saw it.

[@Melanie16040]

Yeah, kinda sad the board got declared dead because he was so concerned at poking at fuzz.

[@timballam3675]

18:07 the track to C3 looks toast along with another underneath.

[@williampz]

Love this type of video.

[@LaserFur]

17:24 this is where kapton tape helps. you can tape it in place and cut the other side and solder one side. then switch the tape over to the other side while you solder it.

[@retropuffer2986]

Good to see you "de bug" the original way! 😆

[@achimboers]

A strange mix of EEV, branchus and Phil’s computer lab… love it Learning a lot. Some things I wouldn’t mind you could explain a bit slower for us mac fan boys. Still learning the pc world.

[@jonnycando]

Intel macs are very similar to pc’s architecturally, and of course you know those macs can run Windows, Linux, Unix, and whatever you like….

[@fortmax05]

Wouldn't the 92-52 indicate the 52nd week of 1992? That also matches with the chip dates you mentioned.

[@Renville80]

Was going to say the same thing.

[@dinomagick]

if its 92-52, with 52 weeks in a year, why would it be written that way instead of 93-00? wait.. computers.. I get it. literally when the chip was manufactured, the computer programming for stamping the date on the chip wouldn't have the .14 'days' ... that would drive my OCD nutz

[@fortmax05]

@@dinomagick Week counting starts with the 1st week, though, so it's 1-52. The last day (or 2 in a leap year) would probably just be part of an 8 (or 9)-day 52nd week.

[@mattj5155]

Uh, guys. You are mis-reading those date codes. This chip was made on the 25th week of 1989. For Intel CPUs of this era only one digit after the L indicates the year followed by 2-digit week. So L9 means 1989 and 25 is the week of production.

[@eDoc2020]

@@mattj5155 I believe we are referring to different parts of the video. We're talking about the 386SX board shown at 5:25. Adrian read 92-52 in the copper layer and then said it probably meant 1995.

[@applesushi]

Years ago we used very similar Bluetooth serial adapters for educational “scribbler” robots in an intro to computer science class. The robots had a serial port and the dongles allowed them to communicate wirelessly with the lab computers.

[@wenpyle]

486DX BOARD and the 286 board MAY REQUIRE CMOS BATTERY they both have ext batt connectors.

[@Melanie16040]

There's also the fact that he broke the trace again while going after those bits of fuzz... That might be the cause of why the board didn't work.

[@nickwallette6201]

Those BT serial adapters would be handy for us IT folk. Makes it easier to stick one on the back of a network switch, router, server, storage appliance, etc., and configure from a laptop without having a cable stretched out from behind a rack. :-)

[@MrLukealbanese]

Wonderful Adrian, great vid.

[@UpLateGeek]

I'm so jealous your 5170 board just worked out of the box, so to speak. I picked up a 5170 board a while back and never got it working. It's definitely a later revision than yours, since there's no bodge wires and most of the chips are dated around mid-85. Interestingly, some of the double-stacked RAM chips have a blue line on them, no idea what that means. And the keyboard controller is a ceramic Intel D8742 with a die window, which is different from the one on your board. I haven't exactly tried much troubleshooting, just the basics of checking for shorts and confirming voltages. I really need at least a POST card to see what's going on. Also, thanks for the tip about using a PLCC socket to connect a different 286 chip. Might have to give that a try someday. Anyway, very cool to see some old school overclocking! And I am glad you at least got some parts working.

[@markae0]

I love the video!. I love the overclocking of the IBM 5170 motherboard. I have to check my stash of old MB to see if they have those bad batteries. Thanks for the warning!

[@Melanie16040]

This was a pretty cool video, not sure how it found me but I watched all of it!

[@davidgeltz7604]

That 286 - 12 brings back memories had one back in the early 90's first computer I built all the parts from tiger direct.

[@iamwonderFil]

i love that eyoyo. i think thats the video you got me hooked.

[@retrotechinsanity]

We use those bluetooth to serial adapters to console into routers in the data center so your laptop isn't tethered to a short cable. Comes in handy in densely populated racks or if your in a tiny closet and there's nowhere good to park your laptop.

[@auriplane]

The microscope really adds a lot to the channel!

[@suluturnip]

Adrian, I love your videos. Thanks for another great one. Your wire tinning skill on the bodge wire is fantastic. Please share some tips on that. I would recommend that you look into getting some tacky flux in a syringe. It will help with those small soldering jobs.

[@markdjdeenix6846]

yes im interested ,you do good content over ][ channels i like this period of technology and you bring it to me thanks Adrian

[@ThePillenwerfer]

I for one found it interesting and would certainly like to see more of the same.

[@alexandrecouture2462]

I miss the time when you could find such a parts box in a garage sale for 3$ :(

[@tw11tube]

55:00 The Harris 80286 manages to stay so cool, because Harris made a CMOS version of the 80286 processor. The Intel processors (EDIT: only some of them) are HMOS processors (which is an NMOS variant). NMOS/HMOS chips have a noticeable static consumption, mostly independent of clock frequency, whereas CMOS gates only get warm when they actively switch something.

[@eDoc2020]

I thought the Intel chip said 80C286 so wouldn't that also be CMOS?

[@tw11tube]

@@eDoc2020 For some reason I got the wrong impression that Intel never made a CMOS 80286. This is obviously wrong. The dysfunctional 12MHz part in the video is CMOS. I couldn't get a good view at the original 6MHz processor, though. Possibly that one still was NMOS.

[@Clavichordist]

I know I'm a bit late to this video. SIP memory is outright awful! I dealt with a bunch of Memorex Telex '386 PCs using SIP memory. The machines would lose memory or fail to post more often than not due to the SIPs creeping out of the sockets. Eventually, the company replaced those machines with something else. On the awesome old IBM AT motherboard, the reason for the slightly bent pins on the ISA slots is that the sockets were installed manually and had to be held in place when put through the wave soldering machine. The bending of the legs prevented the sockets from lifting up. This was a common practice when I worked in PCB assembly in the early 1980s. The terminals I built back then had socketed EPROMs and other support chips as well as the CPUs. We were instructed to bend over the corner pins, alternate corners such as pin 1 and pin 20 and ensure the bent over pins were lined up with the etches. Today, none of this is an issue because these components are robotically inserted or surface mounted and human interaction is taking nearly 99% out of the process. How times have changed in 40+ years!

[@mattparker9726]

50:32 This is why I love your channel.

[@JayVBear45]

Weirdly enough I'm very interested in these early PC mother boards. I remember my brothers talking about working on theirs and occasionally explaining some of it to me.

[@batman4e]

Regarding the 486-DX50, maybe when fixing the trace you have bridged it to the nearby trace. The added wire looks like it is on top of the nearby wire.

[@flashg30]

Hi adrian just to say yes i like those video you do all of them been watching you every time you release something by the way im from canada continue the good work

[@squishy312]

Eat your heart out Linus, this is some real overclocking here! (Was Linus even born yet when this board came out)???

[@eDoc2020]

"Linus Gabriel Sebastian (born August 20, 1986) is a Canadian KZbin personality." So he wasn't born yet. The AT was released on August 14, 1984 so that's slightly over a two year lead.

[@squishy312]

@@eDoc2020 Haha, thanks! I was 5 when this board came out.

[@austrianemotionalman]

Sick OC man!!

[@maltronik]

Yup.. I definately want more of this…. Adrian tqvm…

[@chloedevereaux1801]

i used to work for siemens... all the tantrums diodes resistors ect are pick n place but everything else is hand placed...... thats why the leg bends are different 3 -4 people on the flowline put them in and bent different legs.

[@SidneyCritic]

They make metalic Sharpie colours, ie, silver, gold, etc, that is easy to see on black. I had to make a whole new stand with 1ft reach and a higher column for my makshift microscope. I say keep going, because it is entertaining.

[@chuck2501]

25:17 we have serial interactive whiteboards from 2006 (promethean, still work, why replace) we were looking at these to see if we could make the boards wireless. (esp as serial adaptors are hard to get now)

[@tw11tube]

31:50 It's 4.77 * 3, because the 8088 needs a 33% duty cycle clock signal, which was obtained on the original PC/XT by dividing the 14.31818MHz by three. Intel supplied a suitable clock generator as companion for the 8086/8088, it is the 8284.

[@TheSweetiger]

2:08 for the pci/isa tester , I have one and really like it for diagnostic most pc , include some recent computer, I see the one adrian have , is missing the header under the 4 digi , the header is for an external remote which have 4 digi and the reset botton , also still using it on some recent computer like intel core I 9th generation which some motherboard have a pci on it

[@ConexSpot]

Thanks a lot. Great video.

[@dhgodzilla1]

I use a little WD 40 on Motherboards sometimes to get the Corrosion off & it helps to prevent it too.

[@verishare]

Post'n and Roast'n!!! "Pushing the limits!! "

[@MrVipeg]

Great video, Adrian! But unexpectedly ended :). BTW, your new monitor looks handy, but now we can see almost nothing on it. Do you still have those NEC?

[@MrPicaso72]

Those Varta batteries are the worst. Good video, liked and subscribed.

[@tracyscott3261]

Thank you. I learned a lot.!!!

[@organiccold]

Another long nice video :)

[@madATcomputer]

My first pc had a 486 dx50. Built from used parts from a local computer show.

[@rtechlab6254]

Adrian, get a fibreglass pencil to clean up those tracks. Way better than scraping and much less damaging.

[@SteveJones172pilot]

Pretty sure the firefly modules are basically "Virtual serial cables" using bluetooth for a bridge between 2 PCs.. I had researched similar devices years ago to connect my weather station to a PC collecting data in the basement..

[@donpalmera]

Personally I would get some of the UV solder mask or at least some of the glorified nail varnish solder mask. The problem with clear stuff is it's hard to tell where it is after you've done repairs. You can't miss the coloured stuff.

[@eDoc2020]

If that is a concern, why not use regular colored nail polish? Personally I am a fan of the clear stuff because it makes it easier to inspect repairs. A possible middle ground could be placing a dot of colored nail polish nearby or otherwise marking the board.

[@stevesether]

I had a very similar AMD 386-40 motheboard back in about circa 1998-2005 that was my first Linux machine, and ran my mail server. It looked so similar I thought it might be the same one, but then I noticed yours has an 80387 math co-processor, and mine had a slot for an additional Weitek math-coprocessor. The Weitek co-processor was a competing, incompatible chip with a different instruction set the the 80x87 instruction set. It claimed to be much higher performance than the 80387.The 8087 instruction set was a bit hobbled because it was a strange stack based system where you couldn't directly access registers. The Weitek had normal registers like the main CPU, which I think increased performance. The disadvantage was of course that software had to support this specific instruction set, and most didn't. It was relegated to some specialized scienctific uses where needing a speedy math unit was advantageous.

[@Arti9m]

Nothing stops you from inserting a SIMM slot into a SIPP socket =)

[@eDoc2020]

That idea's as crazy as inserting a PLCC socket into a PGA socket. Nobody's that crazy. Oh wait...

[@eformance]

I have the 386DX-40 version of that SX motherboard. Mine has only 5 slots and all are 16bit ISA. It has 8 SIMM slots and a spot for a math coprocessor. I bought it in November 1993 and it cost just shy of $100.