[sdiy] Yamaha TX81Z FM chips

[Maciej Bartkowiak]

> Hi all. I've just been given a Yamaha TX81Z manual and there's some very
> interesting stuff inside there which has got me thinking. Does anyone on
> this list actually own one of these modules, and if so would they be
> prepared to open it up and have a look inside for various Yamaha chips?
> I'm particularly interested to know which chips beginning with "YM" it
> has.

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).

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.

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.

Oh, yes, there is a HD63B02XP (possibly a controller?)

regards,

MB

PS. Yes, it seems to be possible to replace the transformer with a toroidal
one.
Needs cutting the old one from the separate power supply board. The main
board
is pretty spacious and I wonder why they put the audio outputs close to the
supply