Are there different versions of the FDS?

[Salduchi]

I remember awhile back reading somewhere that there was 2 versions of the Famicom Disk System. If I remember correctly, the first release of the FDS has a smooth Ram cartridge? Is this true, and are there any other different between early release and later release versions of the stand alone FDS? And how can I identify these? Thanks.

[FamicomLass]

I never heard about any physical differences between version of the standalone FDS. If you know where you heard this, I'd be interested.
Later versions do have a different BIOS though, which you can tell apart by the fact that it has less shading on the Nintendo logo and no drop shadow on the text.
First:

Later:

[boye]

I remember awhile back reading somewhere that there was 2 versions of the Famicom Disk System. If I remember correctly, the first release of the FDS has a smooth Ram cartridge? Is this true, and are there any other different between early release and later release versions of the stand alone FDS? And how can I identify these? Thanks.

NERD MODE ACTIVATED
There are two (three?) revisions of the RAM adapter, the earlier one uses smooth plastic and has the drop shadow. The later one uses rough plastic and doesn't have a dropshadow, and the Twin Famicom replaces the Nintendo logo with a Famicom logo.

Meanwhile on the drive itself, there are two revisions of the QD drive itself, specifically the drive controller, the FD7201, and the FD3206. The 3206 has better copy protection, and the power board, which is the board that supplies power and I/O to the drive, has five revisions, and some revisions (especially the later ones) have copy protections. So in total, there is a grand total of 10 possible revisions of the standalone Disk System. If you include the Twin Famicom's different colors, and the Turbo Twin and its color revisions, and assuming that each model and color has the same ten revisions as the standalone FDS, the Twin Famicom has 40 revisions.

If you combine the standalone revisions of the FDS with the Twin's revisions, and assuming that each color of Twin Fami has all the drive and power board revisions, the FDS has a grand total of 50 versions!   

[P]

Well most of them are probably variants of the same boards, so it's probably less.


I saw this on the forum earlier:

Disk Systems are made of a combination of the following 3 kinds of
components:

Power Board

-FMD-01 (fully write capable)
-FMD-02 (fully write capable, unless extra protection board is attached)
-FMD-03 (fully write capable, unless extra protection board is attached)
-FMD-04 (write protected)
-FMD-05 (write protected)

RAM Adapters

FMR-01 (smooth plastic version, glitchy sprite issue happens on this kind)
FMR-02 (smooth plastic version, glitchy sprite issue happens on this kind)
FMR-03 (matte plastic)
FMR-04 (matte plastic)

Drives:

7201 - (fully write capable)
3201 - (write protection)

The RAM test screen is also different on the later versions of the BIOS as seen on Cutting Room Floor.

I don't think I've seen a dump of the early BIOS. Only the later two.

[Salduchi]

Very interesting stuff guys. So it seems the later revisions are probably the best if you want to avoid some glitchy graphics.

Seems like the FDS is the very first console to have a bios. I can't think of an earlier example

[P]

I'm sure there are older video game systems with a proper BIOS. I think ColecoVision do has a BIOS, or maybe at least a boot-ROM.

Besides the FDS BIOS is just for the disk drive add-on. About any disk drive for any system would need a BIOS or boot-ROM with disk access functions. There is no way to boot directly from a disk, some kind of ROM is required, just like modern PCs needs a BIOS to boot the harddrive.

[Salduchi]

Does anyone know exactly what causes the garbled sprites with older RAM adapter? I read on another forum that older RAM adapters work fine on older pre FF Famicom units. Can anyone confirm this?

[P]

It is confirmed that the garbled sprites only happens on certain RAM Adapter and Famicom combinations. I haven't seen a good answer why it happens though (and it's certainly way above my level to understand). I don't know if the degradation happens due to age of certain parts or if it's about rare incompatibility problems of various types of boards due to lack of testing or smaller mistakes done by the engineers at Nintendo or parts manufacturers.

It appears that adding pull-down resistors (4.7 kohm was reported to work well so far) on the 8 data lines fixes it, so it could have been avoided if Nintendo's engineers designed it like that from the start, increasing the cost a little.

[Salduchi]

Thanks P!

[fredJ]

The early FDS units do have a smooth surface, the red surface that is, just like the early famicom console bottom parts. Yes, they also have smooth RAM carts. Besides, the boxes are different too: the early ones open on the sides, while the later you pull up the top, just like normal boxes open.