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Restoring & Learning All About The NEC PC-9821 (PC-98)


The PC-9821 is one of the later models in the now-legendary NEC PC-98 range of computers. In this video I restore this quirky Japanese machine while learning all about its history and how it relates to the iconic PC-88, and how both computers spawned a whole industry of home computer gaming in their homeland of Japan thanks to their advanced graphics and sound capabilities.


This is the story of last year’s summer project - a weird Japanese all-in-one PC from NEC, released in 1996 - and as you can see, this one’s in a bit of a state. I knew it was going to be yellowed and dirty when I bought it for next to nothing, but I didn’t know that the seller was just going to chuck it in a box with only a thin piece of bubble wrap for protection on its 2 month journey across the seven seas from its homeland of Japan.

I’m impressed that there’s anything left of it at all, to be honest.

The insides are even worse as you’ll see shortly. But first, let’s talk a little bit about what these are all about, and what exactly it is that makes them so interesting in the first place.

In 1979, Japanese hardware giant NEC released its PC-8001. It was a very capable machine for its day, featuring a Z80 compatible CPU clocked at 4MHz and 16k of RAM, and could hold its own against and even outperform much more expensive Western contemporaries like the Apple II and the Commodore PET. This led to the 8001 and its even cheaper sibling the 6001 living long lives as affordable entries to home computing, with the 8001 even being one of the first Japanese microcomputers to make it outside of Asia, with variants being sold in Europe and the US.

But why were these machines superior - at least graphically - to western offerings? The simple answer is kanji. One of the three Japanese writing systems, including hiragana and katakana, these highly detailed glyphs are a very important part of the written language in Japan, and although those earliest machines needed add-on ROM cards to actually store the thousands of unique symbols, the onboard graphics hardware at least had to have the capability to display them in high resolution - unlike those early western machines that had to handle barely more than letters, numbers, and a handful of mathematical symbols.

So, alongside the Hitachi BASIC Master and Sharp MZ-80K, the PC-8001 was one of the first batch of Japanese designed and built microcomputers, and really set the stage for things to come.

Now, here’s where it starts to get interesting. It’s 1981, and here in the west, IBM is busy releasing its iconic 5150, the machine that would herald the arrival of MS-DOS and create the template for the next few decades of home computing.

Back in Japan, NEC was busy debuting the 8001’s successor, dubbed the PC-8801, the first in a line of computers that would become the iconic PC-88 series.

Unlike the IBM, which used the Intel x86 architecture, NEC decided to stick with the Zilog Z80 - incidentally the CPU that soon would become the heart of Microsoft’s MSX standard and come to dominate the Japanese market for a few years at least, and of course, a load of other stuff throughout the 1980s.

But let’s not muddy the waters with MSX talk, we’ll save that for another video. All we need to know is that NEC’s PCs weren’t compatible with that. Or with anything else, for that matter - and that was very much by design.

So, it’s at this point that things start moving quite fast. The PC-88 series and, to a lesser extent, the earlier 8001 with their powerful built in BASIC programming environment, fast CPU, generous RAM and industry-leading graphics, started to foster the early beginnings of Japan’s home computer gaming scene.

To capitalise on this, NEC upped the ante with even more capable machines. 1985’s PC-8801MkIISR - catchy name I know - added the powerful YM2203 sound chip as standard - as used in a huge number of popular arcade games including 1943, Ghosts n’ Goblins, Hang-On, Enduro Racer, Darius, Bubble Bobble, Puyo Puyo…

I think you get my point.

This machine also introduced an even more capable graphics mode, known as V2, eventually building the PC-88 into the platform where not only did big names like Koei, Hudson Soft and Square first dip their toes into the world of game development, but more established players like Namco, Sega and even Nintendo ended up releasing their own offerings throughout the series’ lifetime.

So the PC-88 is a legendary series of machines, and with good reason. But how does the PC-98 fit into all this?

Well, NEC had actually released the PC-9801 barely a year after the PC-8801, in 1982. It used the same Intel x86 CPU architecture as IBM’s original PC XT, but in traditional NEC fashion, wasn’t compatible with IBM’s offering in any way whatsoever.

As a much more expensive range of machines targeted primarily at business users, the PC-98 series got off to a slower start, and its completely different architecture meant that it generally wasn’t compatible with games and other software developed for its much more popular predecessor, the PC-88.

But, by the end of the decade, NEC’s business-focussed PC-98 series also established a reputation as gaming machines - partly thanks to their 16-bit architecture and support for much larger amounts of RAM. But more importantly, the PC-98 had another ace up its sleeve in the form of the 7220 Video Display Processor chip, which is widely touted as the first dedicated PC GPU, basically offering the equivalent of VGA graphics - in 1982. The chip was so powerful in fact that it was even licensed from NEC by Intel, who branded it the 82720 and released it as a graphics upgrade for their own PCs.

Of course, this powerful graphics hardware combined with increasingly sophisticated audio capabilities meant that game developers also flocked to the PC-98 series in their droves, and while retrospectively they’re perhaps not held in such high regard as their contemporaries, the FM Towns and Sharp X68000, the PC-98s certainly made their mark on the Japanese home computer gaming market. So where does my PC-9821 fit in?

Well, the earliest machines had used a proprietary 16-bit 100-pin expansion bus known as C-bus, which was somewhat similar in concept to the industry standard ISA bus that began life on the IBM, but added the interesting capability of supporting 32-bit communications by using 2 expansion boards in parallel.

But, by the early 90s there was a desire to import shiny new 32-bit native PCI-based hardware from outside of Japan, with NEC initially releasing PC-98 models with PCI slots, nestled alongside their older proprietary C-Bus slots for backwards compatibility.

As you’ve probably worked out, by the mid-90s the once entirely unique and weird PC-98 series was finally evolving to survive in a market that was becoming increasingly globalised and standardised.

A big part of this was DOS/V - an initiative that allowed MS-DOS to support Japanese text in software. This allowed foreign IBM compatible PC clones to much more easily enter the Japanese market, where traditionally this data had been stored in expensive and proprietary dedicated ROM chips.

Still, the PC-98 range certainly made its mark, shifting over 18 million units by the end of 1999 - reportedly making it the best selling home computer system of the 20th century. At their peak, over 60% of computers sold in Japan were either PC-88 or 98 machines - all manufactured by NEC, as NEC specifically took measures to block compatibles, even developing their own customised release of MS-DOS which was locked to their proprietary hardware.

OK, so it’s perhaps not as exciting as those earlier machines, but it’s still chock full of vestigial NEC weirdness, as we’ll soon see, and certainly has its own interesting story to tell.

More importantly, it was cheap.

But let’s face it, this one was sold as not working and may well have been too far gone to rescue, and I didn’t want to put a huge amount of work into it only to end up just buying another one anyway. So, I preemptively bought another one, which was in much nicer cosmetic condition but apparently had some kind of kanji ROM fault.

Hardware-wise they’re identical, having the same model NEC PC-9821 Cu13/E - the only difference being that one has a /A on the end of all of that, meaning that it was bundled with Ichitaro, a popular Japanese word processor, and the other has a /B on the end, which came with Microsoft Word instead.

Oh, and on the subject of preinstalled software, it seems the list is pretty extensive, with some interesting-looking Disney stuff, kids’ stuff, household stuff, and even a demo of the greatest racing game of all time, so it’ll be interesting to see whether either of these machines has a working hard drive in it.

But first, the teardown. As it was summer and the weather was nice and these things are pretty big and filthy, I did most of the work here in the orangery. That’s right, we call the lean to between our house and garage an orangery because we’re thoroughly upper middle class like that.

After unplugging the monitor power and VGA cables, the PC part slides out of the bottom. I can already see that this one’s actually looking pretty nice inside - well, apart from the neckboard RF shield on the back of the tube - and it looks like some of this surface-level rust has flaked off but it certainly could be worse. So I’ll give it all a good blast out with the air compressor as always.

As it is so ridiculously hot and sunny I’m going to try some sunbrighting on this case while I work on the other one as it’s yellowed pretty unevenly thanks to having a glare filter fitted. I’ve also removed the stickers as I have some reproductions ready to go when I finally put all of this back together.

If you’re not familiar with the process, sunbrighting basically involves leaving old yellowed computer components out in bright sunlight to lighten them up a few shades. It’s supposedly not as harsh on the plastic as the chemical solutions like retr0bright, but it’s not something I really had any experience of, so I thought this would be a good chance to give it a go.

The eagle-eyed among you will have no doubt noticed that the CRT isn’t sitting right in the case, which is due to the mounting posts being broken in transit. I’ll come up with a solution for this later in the video.

I bought these machines from a site called Buyee, which acts as a forwarding service for Yahoo! Auctions, and I also managed to pick up the correct peripherals including a mouse and a keyboard, so I may as well see if I can brighten those up by a few shades while we’re at it too. The keyboard and mouse may look like PS/2 at first glance, but they’re actually proprietary, which shouldn’t be all that surprising, I suppose.

So, while that’s all outside soaking up some rays, I thought I’d bring the PC part inside and see what makes this machine tick…

So here it is, the PC part of the NEC PC-9821. And as you can see, I’ve put the drives back in. These are all cleaned up. This is the hard drive from the dirty PC of course cleaned up. And the reason I’ve done that is because I wanna show you how this fits together because it’s actually quite clever how it’s all kind of structured internally.

So without further ado, let’s start the tear down.

So first things first, to get the floppy drive out we need to take this rail out on this side, which is also a structural part of the case and quite clever, and this also has this integrated card holder which actually supports the PCI cards if you have longer cards in here.

So, three more screws, and out comes the CD changer. This is a four CD changer, and a very interesting looking drive, which we’ll have a look at shortly. But for now, obviously we’ve got the CD audio connected at the back, because this motherboard has onboard audio, and Yeah, just your standard IDE connection for that.

And this is that Seagate Medalist 1. 2 gigabyte hard drive. And I have had a quick look at this off camera, and I have to say there is some interesting stuff on here, so stay tuned. So now we get our first look at the RAM in here, and these are 32 megabyte in the form of two 16 megabyte sims, and apparently these machines can be upgraded to a maximum of 128.

So that’s just one of the 16MB SIMs, that’s NEC branded, which is probably to be expected. And this CPU, if it hasn’t been upgraded or otherwise fiddled with, should be a Pentium 133, but we’ll get some other bits out of the way before we take a closer look at that.

Just your bog standard ATX power supply this is a Delta Electronics branded one, which I think is one of the better of the cheap brands. I haven’t cleaned this out yet, so I think while this is out, I’ll take the opportunity to just blast it out with the air compressor. And of course, this is a hundred volt.

Or 110 volt, yeah 100 volt, because this is obviously a Japanese power supply. Now I could swap this for a UK power supply. The trouble is it’s got the pass through for the monitor on it, so I need to work out how the monitor is powered. But potentially an option, I think I saw a transformer between this connector and the monitor, so there is the potential for maybe changing that and swapping this over to UK 240 volts.

So here’s an interesting thing, a fax modem with a Rockwell chipset on there, and this actually came standard as part of the machine, in fact, it’s labelled on the back of the machine itself. And of course, in Japan, I mean, even today most business is still done by fax. by fax and most kind of official documents and applications for passports and driving licenses and that kind of stuff.

And a lot of people in Japan, you know, will go down to their local convenience store and fax stuff from there for official purposes. But this machine actually has a fax modem built in. And of course there’s the internet access aspect of it as well. So, another interesting little slice of Japanese life here, and this is the TV tuner which actually came standard as part of this machine, and as you can see this has video in and video output on it, it has a VHF aerial, UHF aerial input on it, and I believe that this actually offers MPEG 2.

Hardware MPEG encoding and decoding. So this could also be used to watch video CDs, which were also quite big in Japan at the time. And the reason for this is that quite a lot of people, and like I say, I don’t want to perpetuate stereotypes or make assumptions or anything like that, but quite a lot of people in Japan famously live in quite small apartments and certainly did in the 90s.

And obviously this would take place of the, kind of, the family TV and be used as a TV and a PC. And I think that’s reflected in the fact that obviously there were quite a lot of TVs with integrated games consoles and PCs that were quite popular at the time. So yeah, I think quite a wise decision by NECs on NEC’s part and obviously driven by consumer demand and the trends of the time.

And those PCI cards all plug into this, which is a, obviously it’s a riser, which is quite interesting. PCI only, there’s no support on here for AGP or anything like that. And I think the really interesting thing about this is obviously the, the spacing.

Oh, I’ll just have to stop you there, past Rees just to clarify something. The modem and TV tuner cards interface with other connectors on the case via the motherboard. So I think what we have here is some kind of connector loosely based on PCI but not really, and they’ve flipped them to stop people inserting standard PCI cards. That’s the best I can come up with for now, anyway - although it certainly seems like that bottom slot should be standard PCI.

Anyway, carry on…

And there is our CPU, which should be a Pentium 133. I don’t think it’s an MMX CPU, and it’s very firmly glued on. The heatsink here is very firmly glued on with the thermal compound, so I would quite like to change that. It is usually held down with this metal cage thing, so it doesn’t rely on that to be held into position, but it’d be good to get this off and take a look at the CPU, renew that thermal compound, and give it all a good clean.

So I’ll have a look and see if I can do that.

Yeah, so as suspected, this is just your bog standard 133 megahertz Intel Pentium, not an MMX CPU. To be honest, I already have a 233 MMX machine, and I think I quite like this, this sort of early era of Pentium system, and I think I’d quite like to keep this original spec. I will probably put the RAM out of the other machine in there and just double that.

Just because I have it. So I’ve got 64 Meg, but yeah, CPU wise, I think I’d quite like to keep this original, but the interesting part about this machine is the motherboard. So let’s have a closer look at that. And here is that motherboard. And as you can see, it’s a custom NEC job, very much a custom job.

Obviously you’ve got your socket seven CPU socket there and four SIM slots, which should be pretty familiar. connectors for that PCI riser board, which was very interesting. But I think an interesting part, I’ll just zoom out again for a second. Oh, that’s the wrong way. And yeah, an interesting part is this board on the front, which of course interfaces the motherboard with those front video and game port connectors, which evidently is piped back to that onboard MPEG card and the onboard sound card.

And I’ll talk a little bit about the onboard sound in a second because it’s very interesting. So yeah, it’s a typical Intel VX chipset, PCI chipset from the mid 90s. It has a Trident graphics card, which is a ProVidia 9685, and apparently that has, well that has 2MB of onboard video RAM as well, which is quite cool to see.

We’ve got the Panasonic, this is the BIOS battery here. That sounds a bit crusty, so I will see if I can get a replacement for that before I put it all back together. And I think perhaps the coolest aspect for me as a DOS gaming enthusiast, I guess, is the onboard audio. So this has An actual, genuine Yamaha OPL3 sound chip, which is, of course, famously used on some of the old Sound Blaster 16s and stuff like that.

Very high, highly desirable cards for DOS gaming. And it has a YMF288 chip on it as well, which is, you know, another sort of classic sound chip. It has this onboard header, I haven’t been able to find anything about this, but this is labelled MIDI, so this is evidently for some kind of MIDI interface.

Perhaps that’s what that third slot in the riser was for. For I’ll have to investigate that a bit further. And because this is a completely custom job and doesn’t have a bog standard AC 98 front panel header connectors, as you would expect on a PC of this era. You know, there’s some of a weirdness like the the CD audio connector being over here, and I just thought that that was really cool to see.

So very much a custom job and really interesting looking thing, but I think it’s time to put all of this back together and get on with the restoration.

But of course, we have two of these machines, and I’m really interested to see what the inside of the filthy and battered one looks like - and what a contrast!

This is pretty disgusting… I’m not sure if it was used in a very dirty environment like a factory or something or whether that’s just the way it’s been stored for the past 20+ years. But there may be some spares that I can use here depending on which drives and other bits work, so I’ll clean up the whole lot and see what I can make out of the two.

That’s just a case of giving everything a thorough wipe down with some disinfectant wipes, and then blasting the whole lot out with the air compressor, and then those horrible dirty and yellowed bits from the trashed machine can join their marginally cleaner companions out on the patio table.

So our clean case is actually brightening up quite nicely, and I decided that the cracked CRT posts would be an easier fix than the gaping hole in the other case.

The first step to removing the tube is of course to discharge it. Now, this probably hasn’t been powered up in years and has been hanging around here for a few months, and modern CRTs do have self-discharge circuitry for safety. But it’s best practice and only takes a second, so it’s better to be safe than sorry.

I used superglue to stick these back in place, but as a couple of them had been completely sheared off, of course they weren’t going to be nearly as strong as they were originally.

After some deliberation I settled on this - JB Weld PlasticWeld and - spoiler alert - it works fantastically well. It’s pretty nasty stuff though, so mixing it up and applying it is definitely an outside job, and although it’s not the tidiest of repairs, these posts are now back to being rock solid and should easily take the weight of the CRT. Success!

While I’m in the mood for fiddling with CRTs, I decided to also discharge and remove the tube from the filthy PC, and this allows me to get easy access to the chassis board. You see, whatever impact destroyed the CRT mounting posts on our nice case also destroyed the brightness potentiometer, and it just so happens that I have a spare one right here.

As you can see, this one’s had quite the impact and is definitely beyond any kind of repair, and as I’d have to remove the pot from the other machine to test it and find out the value anyway, I may as well just swap it over.

Oh, and I’m really impressed that my little Pinecil soldering iron runs quite happily from my USB-C power bank. That makes outdoor soldering a whole lot more convenient.

So now it’s time to start reassembling our lovely clean and refurbished PC-9821. I must admit I was a bit nervous screwing the sheer weight of the CRT into those repaired posts but I needn’t have been - they’re super strong now and everything goes back as it should without any issues.

Then it’s just a case of trying to remember where all of the wires and screws went after a few weeks of it all being apart, and this is where being a YouTuber really comes into its own, as I have all the teardown footage to refer back to if needs be. And indeed I usually do, because I’m incredibly forgetful and never take any notes.

So, now we’re in a position to reunite the actual PC part with the monitor and the rest of the case, hooking up the 110V passthrough and VGA connector for the video signal. Of course I’ll be testing both of these, and I’ve left the drives out for now as I’ll need to test those individually and see which ones work - I’m just looking for some signs of life for now so I can make a plan for getting this fully rebuilt.

This Japanese PC needs a 110V stepdown transformer here in the UK, although as mentioned previously I could look at converting it all to UK voltage, particularly if I end up keeping it and using it longer term.

Thankfully this boots up OK - it’s complaining about the hard drive being missing, but of course that’s to be expected. I knew from the initial listing that the other one has some kind of mysterious kanji RAM error, and hooking it up confirms this.

I can always try to diagnose that later, but it’s looking like buying two of these things really was a smart move after all.

As for the drives - I thought I’d try out the dirtier, more yellowed CD drive first and sadly it’s showing no signs of life. These are super cool NEC Multispin 4 disc multichangers and it’s something I was really looking forward to demoing, so after swapping to the cleaner drive I was very pleased to see that the mechanism appeared to be working.

In fact, I actually did a follow up video on this where I showed it doing its thing on the desk, which you may remember from last year. Yeah… That’s how long it’s been.

Taking the old drive apart, I can’t see any damage nor any signs of old CDs. I’ll hold on to it and see if I can do something with it later.

The floppy drives both appear to work so I went with the cleaner of the two, again keeping the other one as a spare. So it’s finally time to get this phoenix of a machine back together, refitting the internal speakers, making sure the wiring is nice and tidy and popping the rear case back on, and finally reuniting the PC with everything else for what is, hopefully, the last time.

So, I’m sure you’re dying to find out whether I managed to recover anything from the hard drive - and there was indeed only the one between the two machines. Well, it’s a bit of a mixed bag, really. I started imaging it, and it made some horrible noises and froze up. So I tried just copying the files and… Same story. I think there’s some physical damage that’s causing it to seize up once the head gets to a certain position.

I did, however, manage to recover some interesting screen grabs from the included TV tuner software - which mainly seemed to consist of low resolution bitmaps of female Japanese TV personalities and sportswomen. Although I will say in the previous owners’ defence that there were also some nice landscape shots and some cute animals - I’m not trying to make them out to be some kind of weirdo or something.

Sadly I didn’t find any captured video - although that might not be a bad thing - and everything else just seems to be either empty or very incomplete folders with the default preinstalled NEC software. Oh, the good news is that the Big Red Racing demo does seem to be mostly intact, and it’ll be interesting to see whether that’s some kind of Japanese localised version.

I did try to boot the PC using this hard disk and - perhaps predictably - it got as far as the Windows 95 boot screen - once - which to be fair is further than I thought it would get based on the noises that it was making. I wasn’t actually recording this but I did get a photo and subsequent attempts were even less successful, so I think it’s safe to assume that it’s finally gone to silicon heaven.

One thing I really wanted to demo was this - the NEC PC-FXGA Game Accelerator board - but I can’t because it uses the older C-Bus which this doesn’t have. This actually allowed some models of PC-9821 to run PC-FX games - ie NEC’s short lived and ultimately ill-fated games console from 1994.

I’m actually led to believe that this card was the very first 3D PC graphics card - and it certainly seems to pre-date other potential contenders like the S3 ViRGE and original Voodoo by at least a few months, but I haven’t been able to confirm that. Ultimately the trouble with these machines is that, what little information there is out there tends to be in Japanese and once it’s translated, it doesn’t necessarily make a lot of sense.

But anyway. The good news is that I’ve managed to track down the original NEC Japanese OEM release of Windows 95 that would have run on this machine, and - somehow - all of the drivers for it too.

So I’d really like to make a followup to this video where I test out the software side of things, the front panel connectors, and the gameport, as well as trying to track down something that makes use of that interesting sound chip we discovered.

And this is where you come in. There must be at least somebody out there watching who’s intimately familiar with these machines and can tell me which of the thousands of PC-98 games actually run on it and are actually worth checking out. So do please let me know - either down in the comments, or you can find links to my Discord server and my email address on my website.

Also, if there’s anything else I’ve missed that’s interesting and worth investigating. But that’s all I have to say on the NEC PC-9821 for now - I’m going to go away and start building up a Japanese Windows 95 environment as close to the original setup as I can get, and I look forward to spending some time with this and getting to know it a lot better now it’s in fully restored and working condition.

Big thanks as always go out to my supporters - whose support not only pays for this studio but also justifies me spending money on this kind of thing - and of course big thanks as always to you for watching, and I’ll hopefully see you next time.

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Relevant Links:
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Credits & References

PC-98 Gameplay Footage courtesy of Basement Brothers:
Arcade Gameplay Footage courtesy of World of Longplays:

Technical Specs:
Bundled Software:
PC-88 History:
PC-98 History:

Kanji image: By Denelson83 - Own work, CC BY-SA 3.0,
Hiragana image: By User:Pmx - Based upon Table hiragana.jpgOriginal autor : Karine WIDMER. ( )From : (archived), CC BY-SA 3.0,
Katakana image: By User:Pmx - Based upon Image:Table katakana.jpg, CC BY-SA 3.0,
Commodore PET character ROM:
Hitachi BASIC Master:
Sharp MZ-80K: By Wolfgang Stief -
, CC0,
Apple II image: By FozzTexx - Own work, CC BY-SA 4.0,
Commodore PET image: By Photograph by Rama, Wikimedia Commons, Cc-by-sa-2.0-fr, CC BY-SA 2.0 fr,
PC-6001 image: By Darklanlan - Own work, CC BY 4.0,
Intel 8088 CPU image: By Konstantin Lanzet - CPU collection Konstantin Lanzet, CC BY-SA 3.0,
PC-9801 image: By MH0301 - Own work, CC BY-SA 4.0,
FM Towns image: By Picopon - Own work, CC BY-SA 3.0,
Intel 82720 image:
C-Bus slot image: By Darklanlan - Own work, CC BY 4.0,

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