Tag: recap

CZ-6MO1 for X68000 – Part 2 – Restoration

Post author By buffi
Post date May 11, 2026

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.

ANALOG PWB

Cap	uF	V	Dia (mm)	H (mm)	Type
C409	4.7	16	6.5	5.6	THT Polar	Digikey
C903	100	25	8.2	7.8	THT Polar	Digikey
C901	100	25	8.2	7.8	THT Polar	Digikey
C905	3.3	25	5	6	SMD Bipolar	Digikey

UNLABELED REAR BOARD

Cap	uF	V	Dia (mm)	H (mm)	Type
C201	100	16	6.5	7.5	THT Polar	Digikey

HAIMEN PWB

Cap	uF	V	Dia (mm)	H (mm)	Type
C603	33	25	6.3	6	THT Polar	Digikey
C604	33	25	6.3	6	THT Polar	Digikey
C610	100	25	7.2	7.5	THT Polar	Digikey

PSU

Cap	uF	V	Dia (mm)	H (mm)	Type
C5	220	200	22.2	25	THT Polar	Digikey
C6	220	200	22.2	25	THT Polar	Digikey
C43-1	330	63	13.5	25	THT Polar	Digikey
C43-2	330	63	13.5	25	THT Polar	Digikey
C23-1	470	50	13.5	25	THT Polar	Digikey
C23-2	470	50	13.5	25	THT Polar	Digikey
C25-1	2200	10	13.5	25	THT Polar	Digikey
C25-2	2200	10	13.5	25	THT Polar	Digikey
C45-1	1000	25	13.5	25	THT Polar	Digikey
C45-2	1000	25	13.5	25	THT Polar	Digikey
C26	4.7	50	5	12	THT Polar	Digikey
C32	4.7	50	5	12	THT Polar	Digikey
C46	4.7	50	5	12	THT Polar	Digikey
C52	4.7	50	5	12	THT Polar	Digikey

Result

Works great!

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!

Basically, maybe don’t buy these for it:

Things turned out great otherwise!

Tags recap, x68000

Old Hardware Retro Computers

Repair of X68000 Pro

Post author By buffi
Post date October 30, 2025

Bought a cheap X68000 Pro a while ago to restore.

Was expecting it to be non-functional and broken, and it was. It was also impressively filthy. Check this out:

Before

Outsides and insides were… very dirty. There were remnants of an old overclock mod which was partly disconnected.

Floppy drives were not present. Neither was the power supply.

What was however present was this sick as fuck homemade RAM card. Look at this thing. Home etched!

Cleanup and recap

Before I could really do anything with this thing, I had to clean out all the dirt, so it was bath time.

Things cleaned up nicely!

As mentioned, there were some partial overclock mods that had to be removed. In practice this meant rewiring a lifted pin from the CPU clock, and bridging a cut trace which was related to the second oscillator for the IO board.

I tried booting things at this point, but things were very dead, so I just skipped right ahead to doing the recap and battery swap here as well to exclude simple issues.

Booting and PSU

With the regular IPL, the system would not boot at this point due to the missing floppies, but with a custom IPL installed, the system would now boot fine from SASI. Very nice!

For the missing PSU, I scavenged some old replacement boards I had around, cut them a bit smaller and made a plastic bracked for mounting a Pico-ATX in the case. Turned out OK.

I decided to not have an internal DC converter, and instead running the device off 12V DC, so I 3d printed a small holder for the connector which turned out well.

Extras

Since the device only came with 1MB RAM, I added an internal 1MB expansion as well as a 8MB Polykubos RAM+Midi card.

For Booting the system, I use a Bluescsi V2 Centronics version. The X68000 Pro does not provide termination power over the SASI port, so I went with a slightly hacky fix of just adding a 5V connector through a hole in the back of the case.

Case cleanup

Stickers were removed by a combination of violence, IPA and scrubbing with a soft brush. Case was washed off thoroughly. IO covers were 3d printed. There’s a few deep scratches but other than that, things look pretty good now!

Final thoughts

There were no real setbacks in this restoration, unlike the Compact I worked on previously.

While there were still a lot of steps to perform to get everything up and running, it was mostly smooth sailing, and I could chip away at it on evenings when I had some spare time.

The lack of floppy drives isn’t too much of an issue to me, since I sortof don’t want to deal with 5.25″ floppies unless I really have to, and the custom IPL allows me to bypass the need for a Master Disk since I can just run SWITCH.X from SASI.

10MHz with 10MB and Midi should be sufficient, but I could look into doing a 16Mhz overclock at this at some point.

Overall a fun and satisfying project.

Tags recap, scsi, x68000

Old Hardware Retro Computers

NEC PC-9801-86 Recap notes

Post author By buffi
Post date February 7, 2025
No Comments on NEC PC-9801-86 Recap notes

Did a quick recap of my new PC-9801-86, and thought I’d add some notes to simplify for other people. There’s an earlier Japanese caplist here that I used as a base, but they used THT caps for the recap which I didn’t want to do.

Note that C33 and C34 are bipolar caps. The mouser links below link to the proper ones, but in my actual recap I just used polarized capacitors which seems to work as well (the Japanese link above did this too). It should be better to use bipolar caps though, so I might swap them later.

Purchase list

Mouser	Amount
710-865090443005	8
710-865060343003	3
710-865230640004	1
710-865090343005	5
710-865250340003	2
710-865230440001	32
710-865060640001	2
647-UWP1C4R7MCL	2

Cap list

Position	Capacitance	Voltage	Diameter	Mouser	Note
C1	33μF	25V	6.3mm	710-865090443005
C2	33μF	25V	6.3mm	710-865090443005
C3	33μF	16V	6.3mm	710-865060343003
C4	0.47μF	50V	4mm	710-865230640004
C5	33μF	25V	6.3mm	710-865090443005
C7	33μF	25V	6.3mm	710-865090443005
C8	47μF	16V	6.3mm	710-865090343005
C9	10μF	16V	4mm	710-865250340003
C10	4.7μF	25V	4mm	710-865230440001
C11	4.7μF	25V	4mm	710-865230440001
C12	4.7μF	25V	4mm	710-865230440001
C13	33μF	16V	6.3mm	710-865060343003
C14	4.7μF	25V	4mm	710-865230440001
C15	4.7μF	25V	4mm	710-865230440001
C16	4.7μF	25V	4mm	710-865230440001
C17	4.7μF	25V	4mm	710-865230440001
C18	4.7μF	25V	4mm	710-865230440001
C19	4.7μF	25V	4mm	710-865230440001
C20	4.7μF	25V	4mm	710-865230440001
C21	4.7μF	25V	4mm	710-865230440001
C22	4.7μF	25V	4mm	710-865230440001
C23	4.7μF	25V	4mm	710-865230440001
C24	4.7μF	25V	4mm	710-865230440001
C25	4.7μF	25V	4mm	710-865230440001
C26	4.7μF	25V	4mm	710-865230440001
C27	4.7μF	25V	4mm	710-865230440001
C28	4.7μF	25V	4mm	710-865230440001
C29	4.7μF	25V	4mm	710-865230440001
C30	1μF	50V	4mm	710-865060640001
C31	1μF	50V	4mm	710-865060640001
C32	4.7μF	25V	4mm	710-865230440001
C33	4.7μF	16V	4mm	647-UWP1C4R7MCL	Bipolar cap
C34	4.7μF	16V	4mm	647-UWP1C4R7MCL	Bipolar cap
C35	33μF	25V	6.3mm	710-865090443005
C36	33μF	25V	6.3mm	710-865090443005
C37	47μF	16V	6.3mm	710-865090343005
C38	47μF	16V	6.3mm	710-865090343005
C39	4.7μF	25V	4mm	710-865230440001
C40	4.7μF	25V	4mm	710-865230440001
C42	4.7μF	25V	4mm	710-865230440001
C43	4.7μF	25V	4mm	710-865230440001
C44	4.7μF	25V	4mm	710-865230440001
C45	47μF	16V	6.3mm	710-865090343005
C46	47μF	16V	6.3mm	710-865090343005
C48	10μF	16V	4mm	710-865250340003
C50	4.7μF	25V	4mm	710-865230440001
C51	4.7μF	25V	4mm	710-865230440001
C53	4.7μF	25V	4mm	710-865230440001
C54	33μF	25V	6.3mm	710-865090443005
C55	33μF	25V	6.3mm	710-865090443005
C56	4.7μF	25V	4mm	710-865230440001
C57	4.7μF	25V	4mm	710-865230440001
C58	4.7μF	25V	4mm	710-865230440001
C59	4.7μF	25V	4mm	710-865230440001
C60	33μF	16V	6.3mm	710-865060343003

Tags pc98, recap

Retro Computers

PC-9821 V13 Capacitor List for Recap

Post author By buffi
Post date July 25, 2024
No Comments on PC-9821 V13 Capacitor List for Recap

Did a full recap on my V13 PC-9821. Here is the cap list.
I did double check the values, but there’s still a possibility for errors, so I recommend checking them yourself too.