X68000 Super - CZ-604C

This is a replacement to the two (faulty) X68000 Pro machines that I bought during 2020.

It was advertised on Yahoo Auctions Japan, as usual, with the following images:

The machine was described as:

X68000 SUPER It is a refurbished operation product.
SUPER comes standard with 2M memory and SCSI port.

The power supply unit and control board, which have many troubles, have all electrolytic capacitors replaced, and some resistors, diodes, and transistors > have been replaced.
The backup battery has been changed to CR2032 socket specifications.
Replace the contacts of the power connector, which is prone to damage and poor contact.
Apply grease after disassembling and cleaning the FDD.
Other parts have been cleaned.

Parodius, Detana Twinbee, operation confirmed on SX-WINDOW JOY1, 2 ports OK
Keyboard terminal OK
Mouse terminal OK
AUDIO OUT terminal OK
Headphone terminal OK
24-hour game demo operation OK

* Other detailed operations have not been confirmed only by checking the above operation is.
* The monitor, controller, keyboard, mouse, game, and software used in the operation check are not included.
* Please enlarge the photo to check for scratches and dirt.

An adapter that converts the controller of the Mega Drive to ATARI specifications such as X68000 and MSX is attached.
Cross keys, B and C can be used.

It looks very clean, without any of the normal blemishes, and clearly some effort has been put in to refurbishing it. Fingers crossed that when it arrives it is actually as good as it appears.

The X68000 Super is the last and newest of the original 10MHz 68000 machines. It was superceded by the XVI & XVI Compact running at 16MHz and the X68030 & X68030 Compact models with their 68030 processor. Unlike previous 10MHz models (the X68000, Ace, Pro and Expert) it has proper SCSI-1 bus support and 2MB of RAM onboard, rather than the earlier (and slightly incompatible) SASI bus just 1MB (though all those machines could be upgraded to 2MB).

It uses the 'Manhattan' tower chassis of the X68000, Ace and Expert, but in the later titanium grey of the XVI, rather than solid black.

[Update 10/03/2021] The X68000 Super landed from Japan. Pictures immediately after unboxing:

[Update 23/03/2021] - Finally got the system mostly connected up and able to test:

  • Power on/off control: working
  • Video output: clear
  • Audio output: clear
  • Floppy drive 1: working
  • Floppy drive 2: working
  • Keyboard: working (via Aranet PS/2 adaptor, Belkin Omniview KVM and Sanwa JPN PS/2 keyboard)
  • Mouse: untested [update 29/03/2021] - connected up the ClassicPC Club mouse adapter and it works great, including the pointer and on-screen virtual keyboard)
  • Joystick: working (via included Megadrive 2-button adaptor)
  • SCSI: untested [update 29/03/2021] - SCSI works perfectly both internal and external

One problem I did encounter was a very, very loud power supply fan; both a combination of a squealing noise and just a very-tired-bearings-are-shot noise. It will definitely need replacing.

Basic Testing

Powering on the system, booting from a Master Disk v3 floppy and a little bit of directory navigation using a PS/2 keyboard adaptor for input.

Game Testing

Trying a game; Gradius II, to make sure that video and audio output is working correctly and testing that the joystick input is okay.

Here's the combined noise of the PSU whine and the original fan:

That's the last 4 seconds of audio from the above initial testing video, amplified by +10dB.

PSU fan was replaced with a Noctua A6x25 FLX to reduce the combined PSU/fan noise. It's a simple job - the only thing to watch out for is changing the 3-pin fan connector of the Noctua to match the 2-pin PSU connector (swap the fan-speed and earth wires on the Noctua, and cut off the fan-speed wire).

It turned out that after replacing the fan, most of the noise was coming from the PSU itself. Now I know that this has had a full capacitor replacement, as it's obvious by the state of the caps and the recent solder job on the underside of the PCB:

Looking more closely, the two middle-size filter caps; C41 and C42, have been replaced with the original values (5600uF, 10v). But, the current recommended wisdom is to uprate these to 6800uF parts, which have been known to cut out PSU noises for several owners…. and this is exactly what I did:

So, did it work?

That's audio taken with the covers off, and the recording made approx 8 inches from the rear of the power supply. Boosted by approx +15dB. There's a tiny bit of white noise from the turbulence from the fan, but it's otherwise silent. I am very happy. :-D

[Update 29/03/2021] - With the case covers back on, and the fan now exhausting through the rear grill, there is a bit of fan noise that wasn't apparent with the case off, but it's very low level and nothing horrendous at all. It's likely that the grill on the case is causing turbulence from the fan exhaust, so there's not much I can do about that, short of cutting out the grill - which I am not going to do.

The X68000 Super has 2MB of base memory, compared to the 1MB of the original model, ACE and Pro, so no internal memory module is needed. In addition it has standard SCSI, rather than SASI of the earlier machines; that means I don't need the SCSI controller board that I bought for the Pro, nor does it need the updated loader storing in SRAM to be able to boot from a hard drive.

I've fitted the following upgrades to the Super:

  • XSIMM10ss - as fitted with a 16MB SIMM to max the memory out to 12MB
  • Sharp CZ-6BM1 - MIDI in/out interface
  • Classic PC Club internal SASI/SCSI hard drive cable and mounting hardware
  • SCSI2SD v5.1 internal adapter

As my Super model isn't a Super HD, it did not have any of the internal parts needed to fit a hard drive. Namely:

  • The SCSI cable only fits from motherboard to back panel - no extension for a HDD.
  • No mounting plate to fit a HDD.
  • Only a 3-pin PSU cable, not a 4 pin AMP/Molex or Floppy style connector

Other than that, the internals of HD systems and the non-HD versions of the same system (e.g Ace-HD vs Ace, Pro-HD vs Pro, my Super vs Super-HD, etc) are absolutely identical: there is nothing to technically stop a non-HD system being upgraded to HD.

Fortunately there are several ways to get around the missing-parts issue - bodge something yourself, or buy a ready-made kit. I was able to buy a complete set from the Japan-based ClassicPC Club, which contains the following parts:

26-pin to a standard 50-pin SCSI-1 adaptor board and internal SCSI extension cable:

HDD mounting panel and correct screws for the X68000 case and standoffs:

With those in place, I could fit the SCSI2SD adapter in place of a regular 2.5/3.5“ SCSI HDD:

You'll note that there isn't a power connection to the SCSI2SD, that's because the v5.1 SCSI2SD boards can get all the power they need from the built-in SCSI termination signals present on (almost) all SCSI cables. That makes the normal problem of sourcing a 3-pin to 4-pin FDD/AMP/Molex power connector a non-issue.

Installing to SD Card

You need to boot from a Human68K boot floppy, or one of the scene “Master Disks”. Fortunately Sharp opened up the licensing for Human68k many years ago and gave it away for free. So you can download a copy of a boot floppy from many places, or here:

After booting, initialise the 'drive' using the english-translated FORMAT.X tool:

Choose the SCSI devices option, and after a second or two the SD card 'drive' should be listed:

If this is the first time using the 'drive', choose the Initialize option. Then choose Create and make a new primary partition no larger than 1000MB in size:

If you want the drive to be bootable (of course you do!), then make sure you have the System File: Copy option selected:

You can, at this point, create a secondary partition, if you require - but, evidence on how large a partition will actually work, is inconclusive. There are reports (in Japanese), that installing GOVERHD.X will increase the maximum supported partition to 15-16GB, but this either isn't true, or most of the english-speaking userbase isn't aware of it.

You then need to tell the X68000 to boot from the drive. Run SWITCH.X and set the 'Boot' option to be the ID of your SCSI drive. Save it and then reboot:

You can also access external SCSI drives on the X68000, using a utility called SUSIE.X. I've detailed how I use it with a SCSI Zip drive.

This is a genuine Sharp MIDI card. I've got it connected to one of the free 'IN' ports on my Kenton MIDI Merge-4 box which takes the signals from each computer I have a MIDI card in (two PC's, a PC-98 and now the X68000) and sends the one combined signal via it's 'OUT' ports to my set of MIDI synths.

Of course, the box is 'dumb', so it's wise never to try and have two computers sending MIDI messages at the same time. This isn't a problem in practice, as I'm unlikely to ever want to play games with a MIDI soundtrack on two computers at the same time!

Fitted with a single 16MB 72pin SIMM and configured to add 10MB to the Sharp memory space, for a total addressable memory of 12MB (2MB onboard + 10MB from the XSimm10SS).

  • Full overview of the XSimm10SS configuration, here: x68_xsimm10ss

This is the absolute maximum amount of RAM you can have in an X68000, short of local high-speed memory on something like the 68040 or 68060 CPU accelerator; but that isn't normally usable by the average X68000 application or game.

  • blog/x68_super.txt
  • Last modified: 2021/03/29 18:12
  • by john