SED9421 datasheet

Door dk_spb

Rookie (24)

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02-01-2011, 22:04

Did anybody have SED9421 datasheet? This is data separator from floppy drive controller Yamaha FD-051.
I have only SED9420 datasheet, but this ICs is difference :-(

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Van Leo

Paragon (1236)

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02-01-2011, 22:24

you do have that floppy disk unit ???

Van dk_spb

Rookie (24)

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02-01-2011, 22:35

No, only photos.
I have trying to make a "copy".

Van Manuel

Ascended (19469)

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02-01-2011, 22:51

Hmm, is it like any other more common FDC used in MSX computers?

Van dk_spb

Rookie (24)

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02-01-2011, 23:43

There are only one "russian" FDC ;-)
Many Yamaha YIS503IIR and YIS503IIIR was installed in soviet schools.
FD-051 was a standard FDC for teacher's computer.
Copy of FD-051 is working now, but I am not sure about capacitors value for data separator.

Van mohai

Paladin (1007)

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03-01-2011, 15:35

SED9420 is a FDC data separator. You can find datasheet in the web.
SED9421 should be a later release with faster speed or support for more disk formats. I am not sure.

Maybe model SED9420 is similar to that.

I found a forum thread ( with some info on SED9421. Somebody posted pinouts ( also.
If you follow the thread, you can get some info.

Van dk_spb

Rookie (24)

afbeelding van dk_spb

03-01-2011, 15:52

Thank you, but no any info about capacitors (or example of external circuits) in this thread :-(
This is info for SED9420