Subj. google give me s#!t
I can guess it's a OPLL sound chip.
Thanks in advance
Are you sure it is 2406? Never seen this index anywhere. OPLL is YM2413,
here is datasheet for this chip.
Here is a good list of Yamaha's sound chips.
I'm pretty sure. Can do proof pic, but little bit later. Date code is 9321 AAAD. Oh, thanks for the link.
As you can see in the list, there are functionally different chips in 24xx indexes, so I'd say, chances that 2406 is a 2413 modification aren't high.
This is the chip. I have few of them. They are definately not fake IC's and they are related to some sort of music equipment
where are these pulled form, any idea ? some old keyboard ?
Hard to tell, probably yes. I've got only board with IC's. There is also some DRAM MSM51C464A and YM3415B
Can ship FREE couple of this IC's as trade for datasheet
Judging by package I highly doubt it is OPLL. Probably something like OPM, if it is FM synth at all. OPLL is cheapest FM synth, it should be in a most compact package (YM2413 is narrow DIP18) and without companion chips.
Is YM3415B actually DIP40? There is no other info around for this one as well.
Yes, YM3415B in DIP-40. Whatever it is, it was made for sound synthesis.
As far as I remember, most of FM synth chips by Yamaha used an external serial DAC. Exceptions that I can recall are YM2413 and YM2612, both are cheap versions of better chips, for toys and such. Initially I had a guess that YM3415B is external serial DAC, then I found that it is DIP40 - way too much pins for DAC. DIP24 is also too much pins for DAC. So if one of these is a FM synth, it probably has built-in DAC.
Unfortunately PCB is 4 layouts or more, so i can't see "pattern"