This NEC PC-8001 is Epic!

[Music] hello and welcome back and I don't actually have that many microcomputers in this room I'm mostly minicomputer focused what with the Centurion and its printer taking up an entire wall we've got the data 620 that's taller than I am the bendex g15 that weighs a literal th000 lbs we have a PDP 1144 with its epic feta Eagle hard drive and we have the Litton mini computer looking a bit like a washing machine I love these large scale systems because they give me a window into Computing that the normal person would never have been able to see otherwise but I also find Micro computers fascinating and I have a few in here I've got the ti 994 with its insane train of side cars I've got the deck rainbow which has an 8080 and a z80 stuffed in inside of it and the Eds PC over here which has a really fascinating story behind it we're going to get deep into that as soon as I get all of the requisite components to bring it up properly in hand but there is one more microm computer that I want to get into and that is this one right here this is an NEC PC 8001 and this one's pretty special to me because it's the first micro computer that I bought which is a strange thing for somebody like me to say but as a kid we did didn't really get into the microcomputer Revolution which isn't to say that I'm super young and missed it as you can tell by the gray hair I'm definitely a product of the 8S but we as a family just didn't get into Computing until the 386 was a thing then I got the bug throughout my entire uh childhood teenage years young adult life and even into an adult I was always fascinated with the newest hottest computer that was coming out I always tried to build a pretty wicked gaming PC and it isn't until recently that I thought you know what I should go back and see what all the hubub was about in the 1980s and of course that led to the 70s Centurion the 60s the data 620 and the 50s the bindex g15 it was kind of a bit of a rabbit hole that I fell down there but back to this NEC PC 8001 when I was getting interested in maybe diving back into this retro Computing scene I was on a business trip to Japan and I was in aaba visiting a pretty cool shop called beep and I was wandering around and I started asking the uh attendance there what the potentially the oldest Japanese personal computer would be and they pointed me at this NEC PC 8001 now this isn't technically the oldest Japanese personal computer I think the master basic system uh Beat It by a year but to me this one's pretty special because it looks way cooler than the master BAS basic system now I got this all the way back in 2018 I never got it working I took it apart cleaned it up made it look real nice and then it set in a corner for the next six years so it's time to get to it it's time to turn this thing into a functioning micro computer that we can then put here in this room if I can find space for it so I have no idea if it works I have no idea how this episode's going to go this is a literal unknown I know nothing about this system as I mentioned earlier I picked this up at beep akaba so this is a proper PC 80001 without the a the 8801a is the one that we got here in the states and so that means that it has a unique keyboard you can see it has all of the Japanese Katakana written on the keys and you can switch between the two with this K button right here which is a uh latching switch which means that it's also going to have some custom roms inside to support the Japanese characters now when I got it there were a few things that came with it like this little sticker here that says nepc 801 and has the uh serial number on it and then we also got this little uh pamphlet right here which has the original warranty card in it I believe uh which you can see it says pc801 has the serial number on it right there you fill this out has multiple carbon copies like this and then you can mail that in that's that's pretty cool to see that stuff with it but I think the really fast fascinating stuff is going to be inside of it so let's pull this top off I've had this part before for cleaning so this isn't exactly new to me but we'll go ahead and pull the top off here you can see I've already got the keyboard disconnected these two normally plug in right down around here uh the power supply I've also got completely disconnected so we'll just go ahead and pull it completely out of the way and there we go that is the motherboard that's the whole computer before we dive into the motherboard I do want to take a quick look at the underside of the keyboard here I do believe that this is a purely mechanical keyboard but that's not what I'm really fascinated by what I am is the string of numbers right here 56.59 this is actually the build date of this machine but that seems really strange what year was it buil in 1956 2056 how do we know that this is the build date well in Japan the official way to write down the current year is to write down what year of the current Emperor's Reign it is so right now we're in the bewa era before that it was the H era and before that it was the Sha era and the emperor during the Sha era was Emperor Hirohito and he reigned from 1926 to 1989 and this machine was built in the 56th year of Emperor hirohito's Reign which equates to 1981 so we have to do a little bit of math to figure out what year this was actually built now the NEC PC 801 I believe believe was released in 1979 so this is a fairly late model of it it been on sale for 3 years by this time looking closer at the motherboard here it's pretty obvious that NEC had their own chip Fab going on all of the big chips here are NEC made but looking at the Heavy Hitters right here we've got the d780 C this is the NEC made z80 CPU right above it we have a d82 57 I believe that this is a CRT controller it might be a dma controller and on that topic the uh one over here is a d331 this might be a CRT controller or a dma controller I couldn't find clear data sheets on these and just looking at the schematics one of them is doing that and the other one is doing something so that's how they go right above the d331 is a d 8251 uh which is a Communications interface uh right here we've got d23 64s three of them right in a row and they say in basic on them so these are going to be the custom Japanese basic ROMs uh and then finally these are d416 C's these are all 16k by 1 bit dams there are eight in a row so that's going to be uh 16 kilobytes and then another 16 kilobytes for a total of 32k of ram but uh you know I've been ignoring the giant elephant in the room which is this strange perf board that's just kind of hanging off to the edge here the previous owner in Japan whoever they were designed this modification board and there are wires all along the bottom of the motherboard here that go to a ton of different ic's so I have absolutely no clue what this does it looks like it has a little LED on there and it has a little push button switch no clue what this is going to be for I'm hoping that once we get this powered up and uh plugged into a monitor that can give us a little bit of insight as to what it does now before we throw some electrons at this thing there's a couple of precautions that we're going to have to take and the first is with the power supply I've already pulled the top off of it here and you can see it is a switch mode power supply and it looks really clean inside there's no Reas or anything that I think we need to worry about except for the fact that Japan's power grid is only 100 volt whereas here in America we're at 120 volts now 100 volts seems really strange but if you look at the back of any cell phone charger that you have you'll see that it often says 100 to 20 140 volts that 100 is so that it can be compatible with Japan's power grid now Japan's power grid still has one more trick up its sleeve but it actually works out in our favor here Japan is split between two different types of power grids one half of the country is on 50 HZ the other half of the country is on 60 HZ pretty wild for the country the size of California to have that but what this means is that every piece of electronics equipment that comes out of Japan has to be compatible with both 50 and 60 HZ so we don't need to worry about having a different line frequency with this particular power supply but the increased voltage here in America is a bit of a concern because you're going to get raw AC coming in through here this looks like our full Bridge rectifier here we have some 100 microfarad 160 volt smoothing capacitors after that and then we get into the switch mode section of it after there and then there's a bunch of smaller electrolytics on the end but those all look in really fantastic shape I think we can just send it as long as we get the proper 100 volts into it and for that just to be extra safe I'm going to use an inverter that takes 120 volts and drops it down to 100 volts ac switch mode power supplies actually need to load on them before they uh stabilize to the correct voltage and uh I happen to know that this power supply is in pretty good shape because you know I do stuff off camera to make sure that I don't look like a complete fool but we'll test it anyways I'll go ahead and flip the power on here and then we'll go ahead and check the voltage rails this should be + 5 Vol right here 4.97 that's looking good it should be + 12 12.6 and- 12.2 this thing is putting out all the perfect voltages that is excellent news on the back here we can get a look at uh some of the ports here we've got our AC 100 volt this is where the actual AC line plug is going to come out the back this is where the power switch goes that's this little guy right here uh and underneath it it says uh dingan and then you have on and off this says uh reset so this is our reset switch this has a little cap that goes on it that's off of it right now so that I don't uh break it off while moving around then we have a cassette Port then these two ports are for display this one says uh shirokuro which is black white and this one says color uh and then over here on the right we've got printer and a guyu bus or external bus but the reason that we're back here is that I need to plug this into a monitor and the monitor that I have that goes with this is a composite Monitor and you can see that there is not a composite plug on the back here however I think there is composite video coming out of this uh black and white port for the display here I just need to figure out which pin is which because if there's uh 12 volts on here and I hook up the wrong pen I can absolutely damage the monitor so we'll start in the top right and move our way around in a clockwise F fashion and uh let's see here top right looks like it's off the scale here and yeah that's going to be a solid 12 volts coming into that so top right is going to be 12 volts uh then moving clockwise from there uh looks like we've got some kind of sink signal going on there that just looks like a uh a pulse then in the middle on the bottom here I'm getting nothing that might be ground uh and then that looks like a different pulse so maybe horizontal and vertical sink are what we're seeing on those two and then the last pin here in the top left uh that looks like a composite video signal actually that looks about right so top left is going to be our composite video and I think bottom middle is going to be our ground and those are going to be the only two signals that we're going to need to actually get this thing working with a composite monitor I think to make up a new video cable for this I'm just going to take an old composite cable that I had and cut one end off of it then I'll strip it back exposing the signal cable and the ground shield on the inside I'll give the wires a nice twist to make them easier to work with then I need something to hold the den plug and this little board that a fellow member of the DFW retro Computing group gave me will do the trick perfectly it's a neat little design with all the different D plug shapes cut out in it so that it can hold your D plug perfectly for soldering and speaking of which I'll go ahead and solder the two wires to the appropriate places on the plug then I'll crimp the strainer relief onto the wire and that's when I realized I forgot to slip the casing onto the wire first after saying a few inappropriate words I took it all back apart and did it all over again finally after it's back together I want to test it with the scope to make sure I got it right and that looks excellent the CRT that I'm going to use for this is this PC 841a NEC character display I bought this here in the state so it runs on 120 volts but it's just a standard composite CRT and it is known good I've used it with the ti99 before and it looks fantastic uh so if the NEC pc801 is going to display anything it should show up here now I don't know I have absolutely no idea what the condition of this machine is we do know that it's generating a video signal so hopefully we'll see something but there's only one way to find out that is a flip the power switch here and here goes nothing oh it just Works uh NEC PC 801 basic version 1.1 copyright 1979 by Microsoft okay I don't have a keyboard hooked up so I have have no idea if the keyboard works but that's fantastic news that looks to be mostly working yes yeah that's awesome I've got the keyboard back on it so let's take this thing for a test drive uh it's just basic so let's type up a pretty quick basic program we'll do 10 4 I = 1 to 10 then we'll do 20 print and then well normally my go-to is halal and if you don't know Halal came about because I was trying to type in hello world in heximal on the memory monitor on the Centurion and uh because I'm unfamiliar with heximal when I was looking down I got to h l o and when I looked down again I picked up at the O in World skipping the space w and O so I ended up with h instead of hello world and that's just kind of become my go-to now that's fascinating because you can actually make the same mistake in Japanese hello world would just be Haro uh but there's two hyphens in there there's two dashes so you can actually look down and pick up at the dash in both and make the exact same mistake skipping the space and the wall so you could end up with har which is the Japanese version of Halal so let's go with that but to type it I'm going to need to push the K key here to get into Japanese input and now this doesn't work like you normally think it would you have to actually look and type the specific conic character and it doesn't really match up how you would expect modern computers are much better about this so you don't have to follow the kna layout but we don't have a whole lot of option here so we'll just do the kna layout here and so that it's going to be uh this one followed by this one and then all the way up to here then this key this key this key and then we'll come out of cona and we'll type an exclamation point and then we'll finish it off and there we go har so we should print that 10 times and then we'll go 30 next I uh and then if we list it should be exactly the same made everything uh uppercase for us now let's run it there we go we printed har 10 times we have officially taken this thing for a test drive that's pretty awesome this thing's working excellently uh I'm going to punch in a slightly more difficult program and then we'll give that a test okay my uh seven key is apparently a little sticky uh sometimes it wouldn't type sometimes it would type double mechanical keyboard it's probably just a little bit dirty the more I use it the better it should get but everything else seems to be working really perfectly it does take me a little while to type in kna on this but I do have the program typed out let's go ahead and run it it should work uh okay so says data which means uh input your data and so we're going to just input a couple of numbers here we'll do 1 2 3 4 uh then we'll do maybe 43 2 1 then we'll do 5565 uh and then we'll do eight just a really wild one and then if you input a zero this should end the program so we'll put a zero in there and yeah there we go so it says uh data this is the number of data ENT are four and that's correct uh go okay that's the total this is going to be all of them added together so that comes out to 11,128 I think that's correct I'm not fast enough to do all of that in my head and then hyen is the average which is 2,782 and you can see how if you get an eight on one of your test scores that really brings the average down but that program worked perfectly that is absolutely awesome now there's some interesting things going on on at the bottom here we have uh HT Auto goto list and run these correspond to the F keys that are up here so if I just hit F5 that's the same for run that should run the program again so if we do 5 five z uh we can see there we go there's two data entries the total is 10 and the average is five yeah that makes sense uh the next one is list so I can just hit F4 to list it out it doesn't list it automatically it just goes ahead and types it for me then I can just hit enter and do that list F3 just types goto for me when you're typing a b basic program go-to is going to be a pretty common one that you use so having that right there is pretty nice uh Auto is an interesting one so I think the way this works is you hit Auto and then hit enter and it starts with 10 now this is going to erase my program but we'll just do a print hellal and then if I hit enter after this it automatically types the 20 for me that's really nice uh so then we can do in and uh and I think I don't know we'll delete outside of that I don't know how to get out of that that's interesting stop okay there we go now we can run that one there we go so turns out hit the stop button on the keyboard I'm learning as we go along uh HT is a tab so I can hit F1 to tab around across so that might be really important for longer programs and then I can hold shift and this changes to different things so we have shift time uh which is a syntax error I'm not really sure how to use that and then shift key it just types key for us missing operand shift print and then that's how we can do our hellal uh and then finally shift continue I'm not really sure what continue means maybe if you have a program that's running indefinitely you can stop and continue from there actually let's try that out let's go 10 print hural 20 go to 10 and then we'll run and then if I hit stop it says breaking 20 now if I hit shift continue yeah there we go I'm learning with you this is awesome we're picking things up so this thing seems to be working absolutely perfectly that is epic I am so happy to have my PC 801 up and running so there is my NEC PC 801 all the way from akaba Japan running absolutely perfectly there is one big burning question remaining though and that is what is this little perfboard expansion thing do and the answer is I have absolutely no clue whatsoever I plugged it in push the little button here the red LED does turn on so it's doing something but near as I can tell basic is not changed in any way whatsoever it performs exactly the same I even wrote a pretty comp computationally intensive program it's on the screen right now and timed it running both with this expansion in there and with it removed and it runs in exactly the same time 18 seconds which rules out the idea that this might be some kind of clock doubler or even clock ha that uh drops the clock speed for homeo projects so I have no clue what this does it's uh complex enough that it's doing something interesting I believe but not so complex that it's doing complex Behavior I mean it's only six ic's and a push button so uh I think what this is going to take is quite a bit of reverse engineering I'm going to need to reverse engineer their kind of point-to-point wiring going on on the back here and I'm going to need to reverse engineer what other ic's within the motherboard it touches which means I also need to figure out what those ic's are doing so I've got a little more work to do to figure out exactly what this is but in the meantime my PC 80001 is running perfectly and uh before we go through one more thing that I want to mention and I said that I wrote a pretty computationally intensive program to kind of stress test it and see if this was uh doing something and that program is Project Oilers question number one this is kind of my go-to whenever I want to stress test a system uh and the question that it posits is what is the sum of all numbers that are divisible by three or five below 1,000 and I discovered a couple coup of things one it takes 18 seconds to run on this machine but uh it does get the right answer you can see I think it's 233,000 lot of capability the thing is humming along at 4 mahz for something released in 1979 rocking 32k of dam as far as home computers go this thing knocked it out of the park I don't understand why it wasn't more popular here in the US I mean they did come here some of them did sell but as far as I can tell this thing is swinging up there with the best of them now I haven't tested the graphical capabilities of it or the color capabilities of it because all I've got is the character display that does black and white so maybe it was let down a little bit there but it seems like in Japan this thing had a massive following with a lot of software for it but this is a fantastic little micro computer now I've got the unenviable task of trying to find a place to fit it in this room so I want to thank you guys so much for watching and I hope to see you in the next episode e

Channel: Usagi Electric

Views: 92,071

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Id: i2L8GDUxxgg

Length: 24min 37sec (1477 seconds)

Published: Sun Mar 24 2024