PC Archeology: This IBM PC XT has a strange appendage

well hello everyone and welcome back to adrian's digital basement 2 second channel video today we're going to take a look at this pc yes another episode of pc archaeology and i know i've done quite a number of these lately so i'm going to breeze through a lot of the standard stuff that this machine has because how interesting is it to look at yet another regular old xt first a little background justin who's a patron dropped off the ibm 5170 and i'm sure you've seen those videos on the main channel he also dropped off three of these xt's and i've already done two videos on taking those apart and taking a look at the inside this was the third and final one and there's not a whole lot to say about this one it's actually an ibm 5160 so it's an ibm pc xt here it's missing the top cover just like the other two xts and the parts inside are you know pretty run-of-the-mill we'll take a quick look at those but there's one thing in particular that is interesting about this machine you'll notice here it's got the original ibm five and a quarter inch disk drive this will be double-sided it does have a hard drive here which you can just see the top of right here it's a seagate i think st225 so 20 megabyte hard drive and it has a tape drive so it's got a little bit going on here but nothing exceptional it's not like it wasn't normal to have these types of accessories in your xt most people had at least a hard drive under the floppy drive but what this machine has on the back which is so very strange is this thing when i saw this i was like what the heck is going on so what this is and let me see if i can get this off there it is it's the micro pack one from everex systems and you'll see here it has an iec connector and this is see there's a regular ibm 5160 back here this clips onto the case with these two little hooks here and then if you align it just correctly it pushes in to the iec power output that's on the back of all of these machines that started with the 5150 normally you plugged your monitor into that connector and when you turned on the chunky power switch it would send power to your monitor i think the ibm 5151 which is the monochrome screen that ibm released with the 5150 it didn't even have a power switch so you had to plug it in to the pass-through to allow you to have that monitor turn off and on with a computer what this thing does is by clipping on the back and connecting to that pass-through allows this to be powered up when the computer's turned on and it still has the pass-through there it is the pass-through connector is there and you can see that this is like some type of auxiliary power supply and then look at this cable the cable comes out of the power supply it goes through this i guess some type of a locking connector which probably unscrews there it is it's like a four pin din or something like that and then it gives this now there's a rubber seal on here and that would imply that this probably should have been installed in some type of a round hole on the back of the computer case and then you would just plug this in and screw it in but someone instead of that has taken this little cover off which if i recall this cover is for accessing the battery on the ibm 5162 i'm not totally sure but let's take this off and look at what's underneath but they basically just took this cover off ran the connector through it and then jam the wires on and put this cover back on maybe when i take this off we're going to see like a db25 type hole in the back of the case that allow you to screw in like an extra port i can't remember no it's just rectangular and yeah i think i mean i don't know what ibm's original intention for this was on the xt but at least on the 5162 which was a 286 in this exact chassis you put the alkaline battery through there it was like in a kind of a little holder i think i've never had one of those machines myself but i seem to recall that was the case now this connector doesn't really fit through here but maybe what's on the other end of this wire does as far as this xt goes it's in pretty dirty shape i don't know i wouldn't say i call it rough shape it was found in the same situation as the other two xts and the 5170 it was in a hoarder house that was being cleaned out i think justin said all these machines were up in the attic meaning they were exposed to a lot of hot and cold weather for who knows how many years and obviously without a cover dirt and everything else would go inside of this machine and potentially moisture and whatnot the 5160 here is very unmolested at least from the ibm standpoint it's a 64 to 256k system board which is interesting to me because the 5150 ended up being released in its lifetime with the same capacity as that and the real only difference between the end 51 50s and then these 5160s was the number of slots because the original 5150 i think only had five slots and this one has eight and there's also only a keyboard port on the 5160 the xt it does not have the cassette port which was next to the keyboard port on the 5150 let's just take a quick look at all these cards that are installed in this machine first one here is obviously some type of monochrome or cga and printer card it's one of the later clone cards so nothing particularly interesting there these were super common and run-of-the-mill next card is some kind of multi-i o card oh and it's got a battery on here it's a ram expansion has a serial port parallel port and a game port and obviously a real-time clock and at the minimum a card like this is necessary to bring this system from 256k up to 512 or 640k also pretty amazing is a varda battery that's very minimally leaked onto the card that's amazing to be honest these cards are quite useful because if you have a 51 50 especially you absolutely need a card like this because the early 51 50s have a maximum of 64k on the motherboard and actually the 5150 that i have is one of those early 16k to 64k motherboards so it's literally 64k pc is all you can do on that machine without expansion next up we have hard drive controller card of some kind the eeprom has an everex sticker does have a western digital chipset but everex is the same brand that is on this here this says everex as well next up we have something with a 50-pin ribbon cable looks like this is probably oh it's an everex systems card as well this is clearly going to that tape drive it's heading out under the hard drive and pop this connector off here you'd almost think that maybe this was a scussy card or something like that but i'm pretty sure it is not there is not nearly enough ics on here for scuzzy so i'm thinking more like an 8-bit ide bus kind of thing like it mostly just transfers the bus these are pal chips here though so there is some custom logic on here this would have a lot more ttl logic on it if it weren't for these four pal chips part number ev8111 rev b and the last card this appears to be probably an ibm asynchronous card oh i don't know if it's ibm or not but it does say async card there serial card has a number printed right here 150 1485 xm and that's actually it for this thing um this is the floppy cable here so the floppy controller was pillaged out of this thing at some point not much to mention for this motherboard though the corrosion from the varda battery did not get anywhere near this motherboard so it is in perfect shape which is pretty sweet so this is the cable that comes from that rear power supply and look at that there's a standard connector there and the other one is definitely going to that tape drive now i'm really feeling that this was probably designed for the original ibm 5150 and not for this machine the reason why i say that is because the power supply in the xt was beefed up over the one that was in the 5150 ibm never intended the 5150 to ever have a hard drive in it was just a single or a dual floppy drive machine i think any accessories like hard drives might be connected externally in a chassis that had its own power supply so solutions like this were probably created to allow you to run an internal hard drive on the 5150 without risking overloading your power supply now the reality is i think it's probably fine to run a 5150 with a hard drive inside in fact the 5150 that i have now i bought from an old gentleman here in portland who owned it since it was new and that machine had the original ibm power supply in it and it had a seagate hard drive in it in fact i think it had two half height floppy drives as well and it totally worked fine but probably if you wanted to stay within spec you needed a solution like this it could also well be that this tape drive that they added in here actually draws quite a bit of current so much so that this stock power supply just couldn't handle it i'm going to do a jump cut to a fully disassembled ibm 5160. the parts inside this machine are all pretty run-of-the-mill this is the tape drive here and it was stacked underneath the hard drive or yeah under the hard drive it did have this piece of cardboard sitting there to try to prevent some short circuits because the main circuit board for this is relatively close to the top there so the hard drive would have been potentially shorting to that probably would have been okay though but there's the front and that is the tape mechanism so the tape goes in sideways it has two spindles that probably come up they look a little bit like the ones on a regular audio tape then you can see the head there it looks like it's at least a two track head and uh yeah i don't really know what mechanism this is the tape drive itself there's the model number to teach mt-2st slash 20d 10 dash u there it is and on the bottom here good amount of components has two motors here so it's a direct drive setup for those two wheels i take it this is a little motor here as well kind of different mechanisms here i guess the loading and the unloading 50 pin edge connector which is very similar to sassy not scuzzy but sassy i don't know what it stands for actually scsi scuzzy small computer system interface sassy is like small appliance system interface i don't really know but anyways it has a connector just like that on sassy drives not much else to report on this tac tape drive floppy drive is the standard tendon one that ibm oems for their machine so this is a double-sided unit they were using these tendon drives since the original 5150 and the belt is kind of stuck on the wheel in fact this is not one of the fabric belts this one is just like a rubber one um that bearing is not great but not not terrible the motor seems okay let's open it yeah that's probably fine a lot of these drives have a fabric reinforced belt those i find to be extremely reliable and durable and they don't really break they don't get sticky or anything like that this one's not sticky but it does not seem like the fabric type let me just see if it's stretchy no it's not really stretchy so maybe this is fabric as well i don't know it does seem to turn pretty well so maybe just a little bit of a wash on this belt will make this drive work properly these drives are extremely robust and reliable what can break though is there's like a little plastic thing here that holds the leverage thing together i don't know if it's the tendon drives that breaks there are certain types of full how full height drives like this or that snaps but there are stl files for those so you can try to print new parts that go in here motherboards pretty standard affair date codes on the chips show the later part of 1984 so i don't remember the exact year that the 5160 came out maybe 1983 so this machine was a couple years old by the time it came out good old seagate st 225 these are generally pretty reliable we'll see if we can read the data off of that power supply is an aztec branded unit it is the original ibm part though it does have a date code right there 40 second week of 1984 so that jives the motherboard and the rest of the stuff we looked at and yeah there's just this extra power supply by everex which we will need to see if it works but i took the cable off here and it's exactly what i thought it was it was just two of the standard molex connectors and this round connector now incidentally i just took a look at the back of my ibm 5150 and that case has a round hole with a little cover over it that really reinforces exactly what i said that this connector was designed to accommodate that exact hole on the 5150 so i do find it kind of unusual that they actually use this on 5160 because i bet this power supply probably could power all this stuff up without the need of this okay over to the bench let's see if any of this stuff still works first let's see if this everex power supply thing works so i have it connected to this old hard drive this hard drive unfortunately it spins up but it doesn't work properly so it's gonna give a little bit of a nice load for the power supply i have the multimeter connected to the 5 volt rail and what you have to do if you want to connect something to this all i need to do is use a regular iec power cord and just plug this in i'll keep my hands away from it because it's obviously could blow up or something like that but let's plug it in see what happens oh it made a very unhappy noise there let's try that one more time i don't know if that's coming from the hard drive or what let's unplug it and see what happens with no load well with no load we're actually getting 5.15 volts let's check the other rail bit high at 13 volts but considering it's got no load on it that is understandable does this say anything about how much it can power what can it give out 110 volts dangerous voltages inside the micro pack one and no it doesn't really say anything about how much current it can give out now this hard drive which is a zbac model 4020 maybe this thing draws too much current so let me just grab a different one here's a random ide hard drive some kind of a conor cp 361 g now this is going to be a lot less current than something like one of those five and a quarter inch full high drives or half height drives that would have been used at the time of this power supply so if it spins this up then great let's see whoa 15 volts [Laughter] well it didn't kill the hard drive but it was giving 15 volts on the 12 volt rail so i'd say that there's probably something faulty about this power supply like its regulation is just not very good and certainly not very trustworthy you don't want to give 15 bolts to your components let me just pop the cover off this thing so we can take a look at the inside obviously speaking of the cover it is a little bit bashed it got squished right here and bent at some point i'm sure that has no uh effect on the internals there it is regulated supply power comes in here there's a fuse and an inline fuse holder we have a four discrete diode bridge rectifier there down here we have the main switching transistor there's probably either on the back side of this board which let me just pop it out of here hopefully there's a little controller or something for the switch mode or it could be using discrete transistors as well the very oops simple feedback circuit there are the internals it says apt incorporated model number sps40a skp394v-0 made in japan and it is definitely a single-sided pcb well there's the backside luckily none of the caps have corroded does have a kind of a conformal coating on there see the glossiness on this section here this is the high voltage section as far as isolation it's actually decent has a decent isolation distance between the low voltage side here and the high voltage size on the low voltage side which connects to the output here probably runs at 12 volts this entire power supply and then this heatsink is attached to a linear voltage regulator which probably goes from 12 to 5 and i see there's a diode here for the output it has a little heat sink on it it's very small output capacitance there's just not a whole lot going on here and the funny thing is i still am not immediately seeing where the switching transistor is out there it is it's right down there so it does just use a regular transistor for switching so very simplistic design for this particular power supply oh here's some more markings here so we have three amps at five volts and we have 2 amps at 12 volts and we do have minus 12 volts dc at half an amp do i even see i don't even see oh yep there's a little tiny voltage regulator down there it's probably for the minus 12 which is not even connected actually right because this thing here is missing a pin because it only is going to 12 and 5. i'm guessing that this was probably designed to work only with that tape drive that's what i'm thinking i don't think this is for hard drives if anyone is familiar like with what this was originally designed to be used for let me know but yeah when it's only giving 12 volts at 2 amps that is not really enough what's overall kind of odd to me about this thing is why did this exist when the power supply in the 5150 and 5160 was a standard form factor if you needed more current in your machine to run hard drives and things wouldn't you just replace the entire power supply with a more powerful unit maybe they were really expensive back then and something like this was cheaper but it just seems a bit odd to have this hodgepodge sort of stick on adapter when you could just swap out the power supply okay everything is assembled but i'm using my known good power supply i'm not going to try the ibm one quite yet i have everything in this machine except for the tape controller card and this monochrome card most likely i'll test this in a second but this pretty much is gonna work i have no doubts that it works fine and this card and the tape drive no real way to test it because i don't have any tapes so not that i would ever use this again anyways so i'm just going to leave this out but the floppy drive is connected i don't have a floppy controller in here yet hard drive is connected to the original controller and because i don't have the video card in here i have a vga card 8-bit vga card connected just in case this thing does work now shorted tantalums i mean we got these boys right here on the board and they're on the drive here and on some of these cards they could well be a problem now when i hit the power switch there could be some fireworks because we have these good old tantalums here and on the drive and on some of these carts here that could be shorted like that is normal but i'm just going to go for broke and give this a try the power supply did go into protection mode so now it's a matter of unplugging things until i figure out what is shorted so let's take this floppy drive off whoa i heard a pop something smokes we got the aroma of burning tantalums let's pop this one out whoo smelly still shorted let's see we'll take the hard drive off and it's controller i don't think it's going to be these still shorted take off this expansion card which i did take the battery off by the way and there was a little bit of corrosion just a tiny bit right under there okay let's see does that make a difference oh nope and we have some fireworks from right there on the motherboard oh boy so the fireworks were coming from this capacitor right here and you see that little black pinhole on it that is where those sparks came out of that's the cap that's causing a problem so of course if you weren't as reckless as me you would take your multimeter and you would test between the black wires on here except on the connector and these various color wires so we have red as five volts i think the yellow is 12 and the uh i don't know orange is probably a negative and then what is the blue power good signal something like that maybe the white is i don't know anyways you would just check to make sure that those aren't bad and we would have had a shorted cap right here so i'm just going to take this off the board come on so i took my snips and i kind of destroyed this capacitor i did that because i wanted to have those legs there so i could more easily pull that thing off the board now remember i've done some videos recently where i've had to change out these these tantalum caps and on boards like this ibm made them really really with a lot of thick copper layers to them so there's a ground plane on here and it makes desoldering very difficult unless you have a proper desoldering iron so my advice is if you don't have the right equipment to just try to break the cap up in a way that leaves the legs exposed and you can just solder the new capacitor right onto those existing legs if you so desire now i'm just noticing that there's actually no markings on this for plus and negative how freaking rude ibm it's not the end of the world you can easily figure that out using your multimeter but it'd be nice if they just had some markings on there with the multimeter on continuity i'm sure i can figure this out so the center leg is not the ground it is the outside two legs that are the ground pins and as is typical with the ones that seem to blow it's probably the 12 volt wire which is this uh yellow one here so that's the third one closest to me here and exactly that's what it is it always seems like it's the 12 volt ones that pop that go bad and short first i don't know what's up with that but that just seems to always be the case either way i'm going to check to see if any others are shortest that's 5 volts and that is not shorted and we have a negative something or other that's fine the orange wire know what that one is that's fine and we have the blue wire yeah so we don't have any other shorts on here it was just the 12 volt one so i haven't replaced that cap yet you could definitely run this board without that mainly that is for the isa slots because sometimes cards use the 12 volt rail but not always and i don't think any of these cards actually even use it so it doesn't really matter so i'm just going to try turn this on with nothing connected and there we go the power supply is running so there's no issues there so i'm just going to reinstall all the cards all right here we are ready for try number two here we go power supply spinning up we oh i don't have the video cable connected let's quickly get that on here now i think i need to change the jumpers or the switches on this so it properly initializes the video card i have to do a quick quick google search here oh no it's coming up anyways it's going to say something about crt error or something around those that because i think if you have it set for monochrome or cga it tries to initialize the bios on the motherboard and the vga card has its own bios so we got a 301 and a 601 301 is because there's no keyboard 601 of course is because there is no floppy controller connected but this thing did turn on look at that it's a survivor my favorite thing to say i have a keyboard connected and i put a floppy controller in here not using the original cable because i need to have a what is a like a 34 pin connector as opposed to an edge connector but it's pretty connected to the original drive here so let's turn this on again i'm just going to stick this cable under the hard drive take the stress off here there we go everything is powering up i didn't even notice how much ram this thing had on the last power cycle let's take a closer look well 128k is what it stopped at and that is definitely not the correct amount of memory i think what's going on actually trying to boot wait it's actually booting the hard drive this hard drive works what what now tried to run some programming it says insufficient memory but it stopped counting at 256k even though clearly there's ram on this card here i think what's happened is that some of this memory on the main board is bad and it's not even recognizing that it's installed so this is 64k 128 you know when you add these two together and then another 256 so there's probably a problem in bank three so it counts the first 128 and then it just stops at the third bank and it just thinks there's no more ram this memory here doesn't work anymore because this would pick up after the 256k to add up to whatever another 256k or probably up to 640k but it has to be continuous if there's a hole in the memory that right away is going to cause us just to stop counting like that now one thing though i need to check that these switch settings are correct they could have been jostled because this computer was thrown you know around in a pile there was i think there were loose parts in it when i found it originally so some of those could have been switched so i need to look those up and see if it's indeed set for 256k on the motherboard first good old minus zerodegrees.net has the switch settings so we need enable banks zero one two and three so that switches three and four need to be off and i can confirm that three and four are set to off i'm just gonna swap them to on and then back to off again in case the connections are dirty inside these switches it switches five and six they need to be on and on if we're gonna have a card that has its own bios so i'll switch those to on and on and then seven eight should be on and on if we have just one floppy drive which we do switch two should be uh on because there's no math coprocessor and that is on and switch one should be off for normal setting and it is off okay let me just power cycle this thing again pretty sure the problem is again ram problem on the on the main board here with this third bank okay same thing it just showed 128k so i'm gonna quickly swap out the main board memory here in bank three try to get this thing working and there we go 256k is working on the main board here the bad chip ended up being this one right here took the chip out i have an x drawn on it the way i figured that out is i found uh nine new working chips and i replaced four at a time i mean i could have replaced five at times or one at a time or whatever but i would i put these first four in i swapped them out with the known good chips still stopped at 128k i did the next four chips and then it counted up to 256k and then i think i replaced these two back with the original it still was counting the 256k i replaced these two back with the original and then it went down to 128k again and then it was just a matter of figuring out which of these two chips it was and it was this chip that was bad now if you don't have extra chips you still could have done this with these chips so you could have taken these and moved them into this bank like swap these two around and basically it would have then stopped counting at 64k because this bank would have counted up and then it would have stopped at this one and the reason why that was happening is probably because this chip that i took out not this one but the bad one was totally dead and what happens on the pc is it looks to see how much memory you have when you first boot it up and if one of the data bits is completely dead that can trick the computer just to thinking that memory doesn't exist at all i think as part of the detection routine it tries to store a little bit of information in each bank of ram and then it reads it back and if it doesn't get back what it expects then it thinks that ram is not there well one dead chip or if you take one chip out it's just not going to see that bank at all so that chip was essentially completely dead if it had had a bit error so it was generally working but say certain bits within this chip were bad then it probably would have counted the memory but then reported memory error and told us which bit was bad because each of these chips represents one bit now remember it's a 16-bit processor but it has an 8-bit data bus so you have eight of these chips plus one for parity and that means that you know each one of these is a you know bit zero one two three all the way through seven so in this case i guess it was what is this zero one two three four bit four was just missing entirely because this chip is just dead and i would have been able to find that by swapping these chips around and then you just have to buy one replacement chip but the 64k memory is the same type that's used on like a commodore 64. and it's so common and easy to get these days that you know if you have a pc like this and it has a ram error like this just buy four or just buy nine chips at a time and then you can do this so i'm going to reinstall all these cards again and restore this thing back and we should hopefully be counting to 640k that is if the memory on that ram card is all in good shape nine of these chips here makes 64 kilobytes of ram so we have 64 128 256 and 384 of memory on this card and 384 plus 256 of course adds up to 640k which is what i expect to see when i power this on so everything's reconnected here we go there we go we crossed over the 128 barrier we're approaching 256k 256k here we go keep on counting let's get to that magic 640k that's still going so the bad ship by the way was a mos tech chip so generally these are pretty reliable it wasn't one of the mt memory chips which are so famous for being super flaky these ones here look to be toshiba chips and look at that 640k ram check past floppy drive just seeked and we should see the hard drive booting here we go it's booting look at that it's running something called qa q a what exactly is q a q a version 2.0 from semantic corporation copyright 1986 file report right utilities intelligent assistant is this like some type of uh smart assistant like we have today let's give that a try this is a database software i guess let's get acquainted hi i'm your new personal database assistant i don't know if you can see that but there's a little ascii art little man there i'm a special kind of assistant you're a software assistant what makes me special is i understand many english requests just tell me in english what you want to know or do and i'll do it for example maybe you have a database of employees you ask show me the address of the sales employees sorted by region and show their spouses too and that gives you the answer here eastern you have two names here their address and their spouse there's a little ascii art guy holding up like a olympic torch the assistant can create reports get stacks of forms perform calculations oh how funny okay so i'm going to ask it to do something oh okay we have contacts employees property and zip these have dates of 1995 on them let's open the employee one enter your english request show me a list of all employees oh it's understanding my english what should i do create a report show the full name and department for all forms okay yeah sure do whatever you think is best all right and there's a list of employees and i i think this is fake data because one of them is called scramble one of them is called scribble monger throck morton and the r d department scribble monger let's just poke around this hard drive a little more and see what else we can find on here we have lotus one two three most likely word perfect five one something called pub something called cc plus new ps qa which we already looked at cc4 quick in three and fastback fastback being backup software obviously i'm looking in the pub folder here uh what is this stuff here let's look at the exe specifically fp i assume this is some kind of like desktop publishing program maybe something like that first publisher and it's has a gui to it now that's super fancy this is a whizzy wig word processor or text processor this isn't too bad considering this thing is running at 4.77 megahertz let's see if we hit f1 for file okay oh looks like it has mouse support f2 f3 we have different fonts available to us monaco oh this is the monaco font let's see if we can load something off of here maybe there's like a demo or something uh save file name i don't really want to save so i'm going to hit no okay hey this is you know i'm i'm i'm relatively impressed by this pushing up and down seems to move the mouse pointer i can't quite figure out how to select something so i'm just going to type it out example.pub i have to wonder if the original card that was in here was a monochrome hercules type card and that this supported hercules graphics which is probably the case it's most likely why they replaced the ibm card with that because they wanted to have this graphics capability um this is it i thought i would see something a little bit more graphical than this okay i'm loading something called menu and that seems to have some actual graphics here first food group dish description fourth food group and they have various things here hey you know this works considering how old this computer is this is actually working pretty neat we have new ps i think this might be print shop let's take a look oh yeah broader bound software broader bounce software presents the new print shop and again this seems to be running in sort of like a hercules mode it's not using the vga itself but this is the more fancy version of print shop uh select printer test printer let's create a new sign or poster i'm going to design my own let's make it wide i'd like to have a grab i'd like to have a border let's make it a wide border oh this is sort of fancy let's use columns why don't we add a graphic here we'll just load it right in the center high res graphics a lot of these are very similar to the graphics that were in the original version of print shop i used to print that print shop a ton on my apple ii back in the day but i'm gonna say i'm gonna put a file cabinet one here okay and we're going to put a message in here i'm going to use this font here and i'm going to say oh you can do different 3d modes let's do solid i'm just going to say please put your files away no okay how do we do preview f10 preview please put your files away [Laughter] oh print shop so good so good there is a copy of basic in the root directory and i just ran this color bar program here using basic a i think it just prints colors using the cga palette yep there it is not much to look at there i don't know why it's like off to the side for some reason that's the monitor not adjusted correctly i typed system to get back to dos yeah they're just not a whole lot on here anything else that's these are just all the basic ibm stuff like the demos and whatever that comes with basic unfortunately there just aren't any interesting demos or games or anything like that on here i loaded up the backup software utility fastback plus so this is uh what they were using to do that if i go to restore source it's showing the floppy drive as a source i assume it would show the tape drive here if that were actually inserted into this computer but it's not so really nothing to look at there oh in case anyone is wondering this is ibm pc dos version 3.2 that's what's installed on here let's see if this floppy drive is actually working first i'm going to give it a quick blow of air then i'm going to use this floppy cleaning disc here to give this thing a little clean on the inside this air i wonder why retry here's a copy of dos 3.3 stick this in here see if this thing can actually read it that's odd it says internal stack failure system halted that could have been something after running these programs let's power cycle this this is actually a bootable floppy so it should try to boot off of it i'm going to pop out this hard drive controller and unplug the hard drive we know it works and it's rather noisy so we're just going to leave that off hmm this is weird the system does not appear to be posting anymore let's just make sure all these cards are seated in here correctly well i have to say this is kind of weird i don't quite get what's happening let me just pop these cards out here see if something died maybe some of this ram died on the ram card here yeah and just like that this motherboard appears to be dead it has gone from working to death that's kind of unusual and it all happened when i tried to read the disc i'm wondering if maybe this thing has a problem on it like a fault in it and 12 volts into the motherboard or something and killed it that would suck but i i can't imagine that was the case but anything is possible i suppose and unfortunately there is no way to use a postcard on these original xts they don't support postcodes so i can't use the postcard to see perhaps it's starting to boot maybe it's failing because there's a ram problem could be that this first bank of ram died or one of the chips went bad and that is what killed it i don't know but i think that's beyond the scope of this video i'm just gonna bust out a different motherboard that does work and just quickly test out this disk drive okay 3d6sx motherboard here have the xt ide connected so it's going to boot off of that i have this floppy drive connected again and i put the original serial card in there so let's just see now if this reads the disk it does read the disk so uh there definitely was not a problem there in fact uh let's reboot the computer and i should be able to boot off this disk drive here let's just give that a try i just need to set this to boot off a i'm gonna also change it to seek and let's see what happens good old reliable tandem mechanisms here thing left for dead oh uh oh you know what of course it's not booting off the a drive because the xd ide will override whatever set in the bios you have to push the a key when the xt ide bios comes up which is now there it is booting off a and there we are dos 3.3 booted off this old floppy drive it works so there we have it another left 4 dead xt machine and it totally worked well it worked up until the motherboard stopped working my hunch is that the ram on bank zero has gone bad because it talked about the stack problem while the stack of course is stored at the bottom of memory and therefore i have a feeling that something in this bank has gone wrong so i'll do a little follow-up video at some point where i troubleshoot the this motherboard and see if i can get this working again but otherwise this thing works another working st 225 these drives are beasts i've definitely had some of these that are bad but more often than not they work and really you're supposed to park the heads on this when you're done using it which i didn't do on this but what i like to do is now that this is working i'm going to put this on this 3d6 on my other workbench and i'm going to run spin right on this overnight with a thorough analysis of the disk surface so it can find and map all the bad sectors and then i can mark this drive as fully fully functional after it's gone through the spin right analysis this disk drive needs a good clean up disassembly just clean out the dirt and lubricate the tracks and stuff like that i will try to clean up the tiny bit of corrosion that's on this ram expansion board these are useful for xt machines and i think everything else in this computer oh there's the power supply i didn't even test that it most certainly will work it probably needs a really good clean on the inside and potentially maybe it has a leaky cap but i doubt it ibm had aztec make a lot of their power supplies they are dead dead reliable much better than power supplies made in the 90s which were flaky and leaky and junky compared to that early stuff so that is it another ibm 60 full of useful parts left for dead almost thrown away and saved so thanks very much justin for bringing that machine to me thanks to my patrons to for supporting the channel if you like this video i'd appreciate a thumbs up and of course it's a second channel so a sub would be very helpful even if you're sub to my main channel i'd like to keep growing this channel and i guess that's going to be it so thank you very much stay healthy stay safe and i'll see you next time bye

Channel: Adrian's Digital Basement ][

Views: 40,568

Rating: 4.9657421 out of 5

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Id: LP0S9PZTb4w

Length: 46min 1sec (2761 seconds)

Published: Tue Sep 14 2021