EEVblog #746 - Sharp X68000 Retro Computer Teardown

[EEVblog]

electronics.de/datenblaetter/Schaltkreise/MB81256.pdf
http://dev-docs.atariforge.org/files/MC68901.pdf
http://pdf1.alldatasheet.com/datasheet-pdf/view/870/MITSUBISHI/M51387P.html
http://www.datasheetspdf.com/PDF/HD63450/774601/1

[EEVblog]

I can normally sometimes resist correcting peoples grammar but, Dave you make this one so often you might as well fix it.

I'd fix it if it was a grammar mistake and not a spelling mistake 

[coppice]

I can normally sometimes resist correcting peoples grammar but, Dave you make this one so often you might as well fix it.

I'd fix it if it was a grammar mistake and not a spelling mistake 

I don't think I can really respect the sought of person who can't be bothered to polish their work.

[Fungus]

Base has 5 screws.... 

[Fungus]

Don't want to derail the thread but ... it reminded me a bit of my old twin-tower SGI VGX (a machine truly worthy of a teardown).



The main tower on the left had a door which opened to show a PCB holder, like this:



Pull the white levers at top/bottom to slide the PCBs out. The PCBs were huge (big enough to need strengthening bars bolted to them to stop them bending under their own weight) and crammed with those vertically mounted SIP RAM packages like in the X68000 (that's what made me think of this).

There's high-res photos of some of the PCBs here: http://www.sgistuff.net/hardware/systems/powerseries.html  (look for "VGX graphics" near the bottom - just the graphics system was spread across four of those PCBs! (or five if you were rich enough to afford two raster managers to get double the pixel fill rate!)

The smaller tower on the right had the power supply at the bottom and you could build it up using stackable SCSI units (containing disks, tape drives, etc). You could stack them pretty high if you had enough money!


More photos here:

http://www.flickr.com/photos/31231773@N02/sets/72157630939129520/

Those things were HEAVY and noisy as hell (multiple 16cm fans at high speed). SGI made a special sling that you could slip underneath with handles so that two people could lift one (usually onto a wooden pallet for a fork-lift to take them to the truck). Yes, I've carried one up some stairs.

Ah, those were the days ... before a $250 PCI graphics card replaced the entire thing.

[cyr]

Are those three F-series chips on the video board really socketed? Looked a bit like ferrite to me, EMI fix?

[bktemp]

Those memory ICs Dave was unable to find any info used in the video setion are dual port DRAMs (also known as VRAMs):
http://pdf.datasheetcatalog.com/datasheets/2300/500355_DS.pdf
Basically DRAMs with an additional SRAM FIFO port for serial IO and internal parallel connection to the DRAM. This allows fast serial input or output of data while the CPU can access the DRAM at the same time.
Using a similar VRAM IC and a microcontroller I built my first DSO and logic analyser many years ago running at 32MS/s. Because all the fast adress counting logic is built into the memory it was very easy to sample all kinds of signals and store them into the large DRAM.

[rsjsouza]

Good video; as someone on the Comments section said, I agree this machine deserves a Part II teardown of the missing components. 

[boffin]

SASI (Shugart Associates System Interface) after the Shugart Hard Drive company - later renamed to Seagate
It was the forerunner of SCSI (which as a standard they didn't want to name after a company) and for all intents and purposes they're the same thing.

[BUkitoo]

Could the cross/arrows simbol at the corner mean the coordinate reference of the board?
The simbol is near a fiducial mark.

[caius]

I have three X68000 machines and I can confirm they are from another planet compared to other personal computer of the same era.Just to say one, CAPCOM used this platform to develop some of they arcade games.Its hardware design is totally different from a normal pc starting from the floppy drive which have a soft-eject mechanism and some proprietary signals on the Shugart bus.If you need further indo about this wonderful machine, I recommend you all to visit this forum:

http://nfggames.com/forum2/index.php#c2

[cbmuser]

I'm sorry, Dave, but the X68000 isn't superior to the Amiga. In fact, it doesn't even compare the first versions of the Amiga.

The Amiga had a preemptive 32-bit multitasking operating system, DMA audio and a high-performance custom chipset for graphics and DMA.
Windows didn't have a 32-bit preemptive kernel before 1995 and MacOS users even had to wait until 2001 (MacOS X).

Just a comparision, here are some typical X68000 games:



And here is a demo that already runs on an original A500:



If you take later Amigas like the A1200, it's even more apparent how superior the Amiga's design was:



No other 68k machine compares to the Amiga when it comes to graphics and sound, except maybe the highend stuff from SGI or NeXT. But those usually cost a couple grands and are therefore out of the comparision.

Adrian

[sunnyhighway]

Could the cross/arrows simbol at the corner mean the coordinate reference of the board. 
The simbol is near a fiducial mark.

To me it looks more like a polarity indicator for the polarity sensitive two-legged components.

[caius]

I'm sorry, Dave, but the X68000 isn't superior to the Amiga. In fact, it doesn't even compare the first versions of the Amiga.

The Amiga had a preemptive 32-bit multitasking operating system, DMA audio and a high-performance custom chipset for graphics and DMA.
Windows didn't have a 32-bit preemptive kernel before 1995 and MacOS users even had to wait until 2001 (MacOS X).

Just a comparision, here are some typical X68000 games:



And here is a demo that already runs on an original A500:



If you take later Amigas like the A1200, it's even more apparent how superior the Amiga's design was:



No other 68k machine compares to the Amiga when it comes to graphics and sound, except maybe the highend stuff from SGI or NeXT. But those usually cost a couple grands and are therefore out of the comparision.

Adrian

Pardon but how can you say this?Do you have an X68000?Try to play perfect arcade ports like Final Fight and many other and you will change you opinion! 
Maybe Amiga hardware was not fully exploited but the software is the touchstone between two machines and the X68000 is far better than Amiga under this point of view.

[caius]

Dave, you can find schematics here:

http://nfggames.com/x68000/Schematics/Outside%20X68000%20-%20Schematics/CZ-600CE%20(Core).tif


http://nfggames.com/x68000/Schematics/Outside%20X68000%20-%20Schematics/CZ-600CE%20(Peripherals).tif


http://nfggames.com/x68000/Schematics/Outside%20X68000%20-%20Schematics/CZ-600CE%20(Video%201).tif


http://nfggames.com/x68000/Schematics/Outside%20X68000%20-%20Schematics/CZ-600CE%20(Video%202).tif

[rob77]

I'm sorry, Dave, but the X68000 isn't superior to the Amiga. In fact, it doesn't even compare the first versions of the Amiga.

The Amiga had a preemptive 32-bit multitasking operating system, DMA audio and a high-performance custom chipset for graphics and DMA.
Windows didn't have a 32-bit preemptive kernel before 1995 and MacOS users even had to wait until 2001 (MacOS X).

Just a comparision, here are some typical X68000 games:



And here is a demo that already runs on an original A500:



If you take later Amigas like the A1200, it's even more apparent how superior the Amiga's design was:



No other 68k machine compares to the Amiga when it comes to graphics and sound, except maybe the highend stuff from SGI or NeXT. But those usually cost a couple grands and are therefore out of the comparision.

Adrian

actually you should compare apples with apples - you comparing a x68000 game with amiga demos...

the demos are using up every available resource to show off the maximum the hardware can do - not leaving a single CPU cycle available for user interaction.... while the games must react quickly to user input and therefore you can't expect the same sound and graphics as in demos...

[Sigmoid]

The Amiga had a preemptive 32-bit multitasking operating system, DMA audio and a high-performance custom chipset for graphics and DMA.
Windows didn't have a 32-bit preemptive kernel before 1995 and MacOS users even had to wait until 2001 (MacOS X).

And how does that have anything to do with the computer itself?!
Besides, most (all?) Amiga games were booted on the bare metal, which means no OS, which means no kernel to speak of.

Just a comparision, here are some typical X68000 games:

...

And here is a demo that already runs on an original A500:

A DEMO?! Really? Come on, you can't be serious! Demos are programming masterpieces that enhusiasts build to show off their absolute mastery of the system and their coding prowess. A demo does not show off the capabilities of a system. It shows off the capabilities of its creator.

To drive home the point... This here is a C64 DEMO:



..while this is a typical c64 game demonstrative of the hardware's capabilities in the hands of a good programmer:



As for which system is more powerful, you should read the specs. And the x68000 blows the Amiga far out of the water when it comes to specs, in sound channels, in number of sprites, in screen resolution, in processor speed, in any actual metric possible.

It's okay to be an Amiga fanboy, but don't be crazy.

[hyperneogeo]

I'm glad Dave got to this and hopefully I'll be able to send more interesting Japanese computer examples. There were a ton of interesting computing devices that were only limited to Japanese markets.

The X68000 had interesting things like Midi cards, Video Card upgrades (nothing 3D mind you, pure 2d), processor upgrades (to 030 / 060 processors) and other cool upgrades. The other interesting thing is the x68000 had a huge huge huge indie game market which led to a lot of interesting games. Recently a few people released a few laser disc game ports on the x68000. Sure you need a very beefy/expensive processor upgrade to do it, but it's there.



Indie Games:







Retail:

The x68000 wasn't really made to do 3D, but people sure did try:






Tons more, but just a few examples. The x68000 was a really nice shooting game system as you can probably tell.

[senso]

So, can it run MetalSlug?

[EEVblog]

Are those three F-series chips on the video board really socketed? Looked a bit like ferrite to me, EMI fix?

Ah, nice spotting, indeed it is a ferrite plate.

[pickle9000]

So will there be a powersupply teardown followup?

[hyperneogeo]

It's interesting to note that many people take the power supply out and replace it with a pico power supply (and rewire it a little) as the original power supply has some rather weird problems.

[Mysion]

That was a rather fascinating tear down. It's not often that you see the insides of a non European/US computer. I'm surprised how well the style held up. It doesn't look like it's 20+ years old. I was assuming early 2000's.

It'd be nice to see a part two of this. What would really be awesome is an analysis on why the power supply is so bad.

Awesome vid!

[Fungus]

actually you should compare apples with apples - you comparing a x68000 game with amiga demos...

Came here to say that. Comparing real games with "demos" is apples to oranges.

The Amiga was amazing at demos but real Amiga games never looked like that (or if they did, they were terrible games).

Edit:

(after a quick google search)

Oh, glub... it's actually on there...!   

Here's a demo I wrote on the Atari ST in the 1980s:



I wrote it just to annoy Amiga fanboys at the local computer shop (skip to 2:05 for the good bit).

It doesn't show well in that video but it was a totally smooth 60Hz parallax scroll over most of the screen. Useless for a game because it used all the RAM and only had enough CPU left for a single sprite, but not a problem for a demo.

That thing traveled pretty much all over the world on floppy disks from a single copy I left in a computer shop. Quite amazing. I remember getting letters from faraway countries for years afterwards asking why I didn't make it into a full game (actual letters, written on paper...)

(And yes, that's how long Amiga Fanboys have been annoying people...)

[bitwelder]

The Cynthia Jr. chip seems to be just some kind of buffer
(From the Video 2 schematics posted earlier)