Famicom Disk System - Repair & 'Upgrade'

Inviere · 26-07-2022 4:59pm #1

So following on from my Famicom upgrade thread, the second part of the job was to get the accompanying Disk System addon working. I've always had a fondness for the Disk System addon, evening going as far as favouring it over the, tbf cooler, Twin Fami's. This particular example was bout as untested, which as always, tends to mean broken/faulty in some manner - and sure enough, it was!

^^ Boxed, in quite nice condition. But does it work?

^^ Well it powers on, so that's a start. It tries to read disks too, which is encouraging. However, that's as far as we get. The drive spins, albeit indefinitely...no signs of attempting to or even failing to read a disk. Ah well, it was to be expected. First port of call will be the drive belt, they're notorious for going bad.

^^ Unit stripped down, and replacement belt ready to go.

The original belt in place. I can't show it here but the belt was VERY loose. It hadn't got nearly enough grip on the pulleys to spin them/drive the head. I didn't think the original belts were transparent (?), so maybe someone tried to replace the belt in the past and ended up stretching the new one they put in? Who knows!

^^ Old v new, you can see the one I removed is quite a bit longer/stretched.

^^ Mechanism removed, and belt replaced. I wasn't looking forward to this as over the years I heard they were a bit of a headache to do. It was surprisingly straight forward however, with the aid of some pictures! There's a nice video I followed that showed a great technique in terms of aligning the heads etc when done, took all of two minutes and worked perfectly first time (I'll link it below.) Unfortunately I forgot to take pics of the head alignment part, but it's shown in the video (the little hex key, loosening the head, rotate the pulley to a certain point, rotate the loose head to new position, and retighten.)

^^ Quick test, chuffed, works first time.

Ok from here on we move towards the 'upgrade' part of the thread. The first part of the upgrade required me to grab an FDSstick...these have been out for years but have completely passed me by...it's a hardware replacement for the entire disk system. A small usb device, that's able to connect to the Famicom via the Ram Adapter, and push *.fds disk images to the machine, therefore fully replacing the actual disk part. I bought it from Tototek, and it took AGES to arrive from Hong Kong, almost 4 months.

^^ Works absolutely beautifully, delighted with it.

Taking it one step further though, it's time to disable the write protection on the Famicom Disk System itsellf, and then when combined with the FDSstick, you can actually write to Famicom Disks. This means if you've old/faulty disks that are unusable (and assuming they are undamaged), you can now re-write a game image to them exactly like the Famicom Disk Writer Station used to, thereby restoring the disk to it's former glory. Better still, you can not only read/dump the contents of the disks, but write completely new disk images to them too. Full Famicom Disk Writer Station functionality.

First step though, is to disable the write protection on the FDS itself (the model I have only needed the power board modded, and thankfully not the drive itself.)...

^^ Traces cut, x2 jumpers removed, & x2 patch wires added in.

For the next part, you need to either buy or build a special cable. It needs to have male Ram Adapter ports on both ends, allowing it to connect to the FDSstick on one end, and to the Famicom Disk System on the other end. Thankfully, these connectors are the very common Nintendo AV connector.

^^ Connectors purchased, and generic 21pin Scart cable bought to act as the cable.

^^ The only modification needed to the new connectors, are to remove the little plastic 'key' on the top of them. This prevents the connector fitting into the stick & the disk system. A dremel is ideal here (though shockingly I've yet to buy one), so I used a sharp blade set to remove the plastic (as well as what felt like a half litre of blood after I sliced my thumb doing it!)

^^ Scart cable stripped and prepped. You only need x8 wires for this cable, the rest can be snipped.

^^ Cable made, secured with internal cable tie, and heat shrink tubing fit to ensure no shorts.

^^ Time to test. Ram adapter removed from FDS, and in its place, one end of the cable. The other end connects to the FDSstick, and then into a PC for use with the FDSstick software. With said software, you can read/write images.

^^ I'm going to first try to read/dump my working Super Mario 2 disk. At least then I'll know if the cable works, before I try writing any images.

^^ Bollox. The mistake I made here is the damned cable is too long, which did occur to me while making it. Drastic alteration was needed to the cable.

^^ I wasn't undoing all the work on the connectors, so I just decided to snip the cable shorter, and simply join both ends. This meant removing the shielding and all the extra/unneeded wires too, so while it looks less polished now, it's much more lightweight and hey, it should actually work now!

^^ Yus! The shorter cable works. My SMB2 disk was dumped to the desktop in only a few seconds.

^^ Testing the newly dumped disk image via emulation, it was flawless. Looking good so far!

^^ Here's my 'unreadable' disk. It seems to have originally been an ExciteBike disk, but it came in a Karate Champ case....anyway, it doesn't play anything and bounces an Error 27 when I try to read it. Perfect candidate for a write-test.