To use it, burn the IPL in bin/ to EPROMs for your X68000 IPL slots.
What this does
When starting the machine, this replaces the stock IPL (BIOS) with a systems test. Optionally, you can compile the Test IPL to boot into a real IPL once the system tests have completed. The default files in bin/ in the repo DOES NOT contain any Sharp IPL data, so you will have to supply that yourself if you want to do the chaining.
It will do some simple communication with various onboard peripherals, as well as run a memory test. See the repo for more details.
Finding an issue with the RTC in my X6800 Pro
When trying this out, I noticed that the RTC Oscillator test was failing. Turns out this was a real issue, and time was not advancing. Some quick investigation showed that the variable capacitor near the RTC was busted.
This version is slightly different from the other version(s) which have footage on Youtube.
I have dumped it. It is now available at archive.org.
Install instructions are further down in this post.
What is this thing?
Chobi Ren Sha 68k is a conversion of Cho Ren Sha, which swaps out sound effects, boss sprites and music to other assets. Gameplay is unchanged.
It was created by Fumi of the doujin circle CYNTHIA in 1997.
The most interesting part of this release is that it’s semi-official, in that Yosshin apparently collaborated with the doujin circle that made it, and the original composer for the Cho Ren Sha music Loser Kachigawi wrote the music for this as well (this can be confirmed by looking in the dev diaries present on the floppy).
Somehow it has gone undumped until now. This is likely since I suspect not a lot of these floppies were sold, and I’ve only ever seen it up for auction twice. This one which I managed to snag, and in a huge doujin bundle a while back which went for too much money (see pic below).
The old auction I didn’t win
While this is a VERY niche release, as a big fan of CRS68k, I’ve been very curious about it, and it’s been a bit of a “grail” of mine to find.
Version differences
At least three versions of Chobi Ren Sha 68k exist. This one, which is a conversion that’s applied to an existing CRS68k 0.6 installation, a later floppy version for CRS68k 1.0, and then an even later CD-ROM release, which I believe also has a version for Windows (see discussion here).
Since this early version was made before Stage 0 was added to Cho Ren Sha, there is no updated Boss sprite in the 0.6 release.
One very fun find is that the Boss 1 BGM from Chobi Ren Sha 0.6 is actually a PCM version of the TLB music that was used in the 1.0 version of Cho Ren Sha! See video below:
Examples of some sprite differences between the versions:
Stage 1 Boss in 0.6Stage 1 Boss in 1.0Stage 2 Boss in 0.6Stage 2 Boss in 1.0Stage 3 Boss in 0.6Stage 3 Boss in 1.0
I am hoping to track down the other versions too at some point, but it’s at least nice to have one preserved dump out for this now 🙂
Gameplay
Here is a quick video of me playing through the first loop of the game.
As you can see in the video, some of the boss sprites are quite different from the release used in other Youtube videos right now.
Installation instructions
Instructions are for original X680x0 hardware. I don’t have much experience using emulators, but I assume it should be similar there.
This version of the game is really made to run with Cho Ren Sha version 0.6 (Comiket 52), but since that version is undumped, and you probably want to play a later version anyways, here’s what I did to get it running with CRS68k v1.01. That version lacks a few of the earlier PCM files, so they need to be grabbed from an earlier version.
It seems to run fine like this (see video above), but it’s possible some stuff is wrong compared to using this with CRS68k v0.6.
Requirements:
X68000 or X68030 with at least 15MHz cpu frequency.
This is apparently to handle the additional PCM, as noted in dev diaries on the floppy.
Copy pcm_dat/shot2.pcm and pcm_dat/fmake0d.pcm from CRS68k v0.45 to pcm_dat/ for the v1.01 install
Copy all Chobi Ren Sha files into the same folder as well
To get the TLB music to work, you need to add the lines at the code-block below this list to BGM_DAT/sz2_bgm.cnf at the top of the ボスBGM section*.
Run チョビるぜ!!.BAT to start. (You may want to rename this to something easier to type)
Enjoy!
*Stuff to add to BGM_DAT/sz2_bgm.cnf:
* True Last Boss
BGM_No.$20 : FILE = BGM_DAT¥るざりん¥SZ2_B3.MDC
I do realize that these instructions are somewhat complicated. Someone else might want to distribute a pre-patched LZH file with the contents of this at some point and/or include this in the SCSI HDD images with games that people tend to use nowadays.
Misc stuff
The only footage I’ve found of people playing this game (the later version):
I looked around a bit recently on what’s possible to do with the USB port of Nereid on X68000, and saw that the currently available drivers seem to be:
Mouse
Gamepad
USB Floppy drive
… but I couldn’t find anyone that have written drivers for using USB memory sticks as hard drives.
Have been messing around with this quite a bit now and seems to work really well. Since the drive mounts as FAT16 instead of using binary images like BlueSCSI, it’s now extremely easy to transmit files between my computer and the X68000!
Since this is just something I shat out kindof quickly with a LLM, I can’t say I’m particularily proud of this thing, but it’s a weird new world we live in now when making these things is suddenly easy.
If I were to implement this myself, it would have taken me weeks/months of research to figure out how to approach it. Now I can just prompt some machine in the cloud and it spits out a surprisingly well written device driver for and old machine like this.
I have a X68000 setup at my work desk which I only use for games, and I found it annoying to have to reach for the keyboard every time I wanted to launch a game through LHES.
My initial thinking was that I could create a custom game launcher which supported controllers, or modify LHES to have support for them. After thinking about it a bit, I realized that a better option would be making a utility for mapping joypad inputs as keyboard inputs.
I wasn’t initially sure if this was possible, but after some experimentation, this turned out really well!
As an example, to use LHES as a launcher with the standard SCSI image that people are using (with !Start.bat scripts for launching games), you can run:
Player 1 controller is used for navigating into games (Double tap B to quit LHES and run !Start.bat). Player 2 controller is used to swap between HDD drives.
No changes are needed to AUTOEXEC.BAT/CONFIG.SYS. Just run the util to remap things.
Only tested with LHES, SWITCH and ED so far, but should work for a lot of stuff.
Note that since this relies on hooking things up to the VBLANK interrupt, apps/games which require ownership of this will NOT work.
A while back, I bought a cheap X68000 Compact that didn’t boot, and fixed it up well enough to be able to boot in 10Mhz mode, but not 16Mhz mode.
This involved both fixing issues with RAM accesses + bad logic IC’s related to audio. See earlier post here.
Considering it was bought broken and that repair took a lot of debugging, I was mostly happy with that outcome, but wanted to get back to fixing the 16Mhz mode too.
This summer, I finally went back to it and managed to fix it, so here’s a quick writeup.
Figuring out the crash
I started by probing the address lines of the X68000 until HALT was asserted, and noticed it crashed at the same spot as it did previously in 10Mhz mode before i fixed that mode.
It fails after a read of FF0636 which is a RTS instruction. The return address is incorrect, and things blow up.
Since that was what happened originally in 10Mhz mode, I could just assume that my previous fix was only _mostly_ correct.
Probing the RAM IC’s verified that only two of them were getting CS pulses in 16Mhz mode when LDS and UDS were asserted, while they all were in 10Mhz mode.
Looking back at the earlier “fix”
The previous fix I had for the RAM access was:
IC84 Pin #13 -> IC84 Pin #4
IC84 Pin #7 -> ASA Pin #3
ASA Pin #3 lifted off pad
This was inspired by the schematics for the non-compact X68000 XVI (CZ-634C), since the schematics for compact was not available, and it appeared to be wired the same when inspecting signals.
Going back and reverting those fixes and probing things more carefully, I noticed that the compact does NOT have this exact wiring though.
When looking at UDS which were known to work, I can see that Pin#15 and Pin#6 are wired together, and continuity testing shows that this is also wired to the ASA UDS port.
On my machine, I could see that IC84 Pin #13 was NOT connected to Pin #4, which seemed weird, since I’d expect LDS to be have the same as UDS. Trace should be under IC, but assuming trace damage, the previous initial patch was correct.
What was wrong was the IC84 Pin #7 -> ASA Pin #3 part (which should be correct on the non-compact).
Simply reverting that fix, and cleaning up the bodge a bit made the machine boot in 16Mhz mode too.
Happy ending
Very glad to have this fixed. Machine now works 100%. Getting sidetracked a bit by messing up the wiring in the previous repair was awkward, but simply going back and probing things carefully made for a rather quick fix!
The best type of mistakes are ones that can be easily reverted.
In the earlier post I wrote a little about the CZ-6MO1 Magneto Optical drive I bought for Sharp X68000.
Unfortunately, after some use, it smelled of dead capacitors (fishy and bad), and I was getting inconsistent results with reading disks.
Since this thing is old, I opened it up and did a restoration. This post covers this with some pics, and then a cap-list towards the end.
Opening the device
With the top off, the drive looks like this. The PSU is facing the camera and behind it is the MO assembly sandwiched between two PCBs, with another two sitting behind it near the back fan.
PSU is fairly beefy. 3A on 12V and 3A on 5V.
Popping off top reveals back of one of the “Analog PWB”. TONS of variable resistors, which I guess are used for fine tuning this thing. There’s some flux residue ot something, but nothing here looks very bad.
Popping off the rear part with connectors and fans reveals the rear boards, which are stacked on top of eachother with a connector.
Removing top PCB requires being very careful, since it has a flex table which is kindof short. Moving it like below, and then unclipping the connector worked well.
Top board is kindof dirty, and some caps look iffy.
Now the main MO drive assembly can be removed and flipped upside down. Removing the cover there reveals another PCB
Apparently this is the digital power board. This looks clean and no electrolytic capacitors to worry about.
At this point, things were as much dissassembled as I dared to go. The Drive itself could be opened up further, but I have no experience servicing MO-drives, so I thought it best to leave it as is for now unless I notice issues there.
Power supply opened up easily and the fishy smell was strong there.
Bulging and leaking caps, bad times. Needed some real work.
Recapping
The only restoration I did on this thing as this point was a good cleaning and a full recap of all the boards. This turned out to be sufficient.
The caplist I made is below. Measurements are not exact, but get something close enough and it should be fine. Digikey links are what I used. For some, the voltage rating is upped a bit compared to the board ones.
Interestingly, after recap I got these Fujifilm disks to ALMOST work too, which I had zero success with before recapping. They will initialize fine, but they seem slower and make a lot more noise when reading/writing compared to the Sony ones. After copying some files to it, the system will no longer write more data. Not sure if that’s an issue with my unit or if these are incompatible in some way.
I will just use the Sony EDM-1DA1 ones in the future due to this, since they work great!
Won an auction for this very rare peripheral for X68000 a while back.
This thing cost a massive 450,000yen at launch back in 1990, with each disk costing 30,000 additional yen… but they could hold 594MB of data, which was pretty insane back then, considering the X68000 HDD’s were more like 40MB.
It reads 5.25″ MO Disks, and they need to be 512 byte / sector with a total max size of 594MB (spread across two sides) to work. I tried some large MO disks and they did not work.
The ones sold with it back then were JY-701MPA, but I haven’t been able to trace down any of those.
The one’s I have that I managed to get working are Sony EDM-1DA1, but I’m sure other models would work too as long as having correct specs.
Setup
Connect the device to a SCSI port on your machine. SASI devices will need a SCSI expansion card.
Load a MO disk and power on machine and disk drive.
Boot a Master Disc floppy
Run
cd sxsi
scsiformat
In SCSI format you want to do the following things:
Initialize disk (5)
Don’t do the low level format, just initialize.
Create a partition (2)
Use maximum available size
If you want to boot from it: Make it bootable by going into Bootflags (4)
Repeat for other side of Disk
It should look something like this when done:
Boot from it
To test booting from it, after making the partition bootable, I just copied the master disk contents to the MO disk with
A>COPYALL *.* C:
Then run SWITCH.X and set the machine to boot from SCSI ID 1. Works!
Unfortunately this thing has a vague fish smell from bad caps, so I need to go through and recap it now, which should be a fun project.
Tracking down that issue took me a few months, but I only managed to grab it along with a bunch of other issues, so now I have a lot of stuff to go through at some point.
Anyways, the Japanese site was correct and there definitely was some fun info in their. Looks like there’s actually a small prefix in the earlier issue as well though.
1991 September I/O Magazine
This magazine goes through a bunch of hardware for X68000 at a high level, and it has two pages with high level info on CZ-6EB1. This also mentions that the author has made their own expansion.
Info on that one is in the next issue and it’s… quite something.
1991 October I/O Magazine
This magazine shows a pretty impressive DIY build of a IO box. The cable spaghetti is… interesting.
It’s still a rad project though, and I kinda love that magazines used to publish these kinda projects.
