[sdiy] Yamaha TX81Z FM chips

[Happy Harry]

If you all remember... the FB-01 was an earlier unit that was
pretty much NON programmable... although there were aftermarket
upgrade kits to give it that capability.

Once the TX81-Z was introduced... the value of the FB-01 dropped
to nearly zero.

The FB-01 was a market answer to the Roland MT-32.

H^) harry


>From: Richard Atkinson <rga24 at cantab.net>
>To: Synth DIY List <synth-diy at dropmix.xs4all.nl>
>Subject: Re: [sdiy] Yamaha TX81Z FM chips
>Date: Thu, 28 Feb 2002 02:45:02 +0000 (GMT)
>
>On Thu, 28 Feb 2002, Maciej Bartkowiak wrote:
>
> > Richard,
> >
> > I just opened mine to have a look for the synth engine chip as well as 
>to
> > see,
> > if the horribly humming power transformer is replaceable and if there is
> > some
> > space to fit an analogue filter in (my plan).
>
>Thanks very much! I'm extra-ordinarily grateful!
>
> > There is one DIP24 YM2414B and I think that's it. There is a YM3012 
>small
> > DIP16 denoted as IC12, located close to 2 x JRC6046 +  JRC6074 + JRC6253
> > (looks like output buffers), and I suspect the 3012 is a DAC.
>
>Yes, YM3012 is a stereo serial DAC using floating point representation (10
>bit mantissa, 3 bit exponent).
>
> > There is a 5564 from Toshiba (a SRAM for storing patches, I guess) and a
> > socketed 27512. This may be a factory patch set, which suggests a
> > possibility
> > to reprogramme these - great news, if I only knew the encoding scheme.
>
>Curious. FB-01 has two 8K SRAMs.
> >
> > Oh, yes, there is a HD63B02XP (possibly a controller?)
>
>Whereas FB-01 uses an ordinary Z80. I wonder why Yamaha shuffled the
>design around so much. I always thought these two modules were supposed to
>be very similar.
>
>
>Richard
>




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