SY77 DM1 board/firmware versions (with pictures)

Yamaha SY77 is a 16 voice multitimbral music workstation first produced by Yamaha Corporation in 1989. The SY77 is a synthesizer whose architecture combines AFM (Advanced Frequency Modulation) synthesis, AWM2 (Advanced Wave Memory 2) for ROM-borne sample-based synthesis, and the combination of these two methods christened Realtime Convolution and Modulation Synthesis (RCM).

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SY77 DM1 board/firmware versions (with pictures)

Unread post by Rara »

These are the different version of the mainboards (DM1) in the SY77.

I have only illustrated the first three I know of, I don't have, nor seen versions 1.4 or 1.5.
If anyone has a picture of these two they don't mind sharing, please do :)

First is v1.2
Hitachi H8/532 CPU and 4 socketed eproms. (Upper right) main rom date November 25 1989 unit serial QH01231

SY77_DM1_v1.2.jpg
SY77_DM1_v1.2.jpg (105.25 KiB) Viewed 417 times

Second is the first version of 1.3 same CPU only two eproms in sockets.

SY77_DM1_v1.3a.jpg
SY77_DM1_v1.3a.jpg (101.73 KiB) Viewed 417 times


Third is also v1.3, only the eproms have been soldered to the board. Main rom date February 15 1990 unit serial PZ04107

SY77_DM1_v1.3b.jpg
SY77_DM1_v1.3b.jpg (98.97 KiB) Viewed 417 times


I'm not 100% sure which version the following is, possibly 1.5?

SY77_DM1_v1.4-5_Kyoichi Sato_CCA_4.0_resized.jpg
SY77_DM1_v1.4-5_Kyoichi Sato_CCA_4.0_resized.jpg


Rara 0-)
Last edited by Rara on Sun Nov 15, 2020 4:48 am, edited 1 time in total.


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by bnz99 »

Thanks again for posting this. I'll make a better picture of my 1.2 board when I open my SY77 next time (once I have flashed and modded my Gotek drive with rotary encoders and oled display). From the not so well done pictures I took last time of my 1.2 board (unfortunately, the DM1 board is only in parts on it), I could at least see that my 1.2 DM1 board has a rather small main CPU/IC101 soldered on and only two eeproms. I can't see from the picture I currently have whether they are socketed or soldered, I think they are soldered as the empty ones don't have a socket. So it is kind of different from your pictures, is more similar to your "possibly 1.5" picture and kind of irritates the differentiators a little. I think it would be cool to collect more DM1 board pictures from people who open up their SY77 anyway.


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by shadowmask »

Here's another one.

The legend in the center of the board suggests PCB Rev D.

Also at the bottom center is a PCB date legend. This one appears to be 1989 [9]. I'm not sure if the dot inside the final square means December or the final space is the month (November).

DM1_TOP_FULLx.jpg
DM1_BTM_FULLx.jpg
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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by Rara »

bnz99 wrote: Thu Nov 19, 2020 9:33 pm Thanks again for posting this. I'll make a better picture of my 1.2 board when I open my SY77 next time (once I have flashed and modded my Gotek drive with rotary encoders and oled display). From the not so well done pictures I took last time of my 1.2 board (unfortunately, the DM1 board is only in parts on it), I could at least see that my 1.2 DM1 board has a rather small main CPU/IC101 soldered on and only two eeproms. I can't see from the picture I currently have whether they are socketed or soldered, I think they are soldered as the empty ones don't have a socket. So it is kind of different from your pictures, is more similar to your "possibly 1.5" picture and kind of irritates the differentiators a little. I think it would be cool to collect more DM1 board pictures from people who open up their SY77 anyway.
Your welcome
When you next have your sy77 on, press together the buttons labelled voice + D + 8
This will show main rom and seq rom version
Yours should show either 1.4 or 1.5 main rom.
shadowmask wrote: Fri Nov 20, 2020 8:30 am Here's another one.

The legend in the center of the board suggests PCB Rev D.

Also at the bottom center is a PCB date legend. This one appears to be 1989 [9]. I'm not sure if the dot inside the final square means December or the final space is the month (November)

Brian
Thanks for the picture, better than mine :)

The dot in the square, possibly means November. Produced in November
For the December release. So it could be a 1.2.

I often thought the number in the box to the left
Would indicate the year. 9 is 1989 and if you look at later boards
They have 0 or 1 which I believe would be 1990 or 1991.

Rara 0-)


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by bnz99 »

Well, it is ROM 1.2 ;-)
20201120_094152.jpg
20201120_094152.jpg (34.44 KiB) Viewed 322 times
As I said, the quality is bad, but it is clearly visible that the CPU is unsocketed and soldered and only two eeproms are on it despite the fact that it is ROM 1.2. Kind of odd...
20200806_201801_1.jpg
20200806_201801_1.jpg (79.23 KiB) Viewed 322 times


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by Rara »

bnz99 wrote: Fri Nov 20, 2020 10:37 am Well, it is ROM 1.2 ;-)
20201120_094152.jpg

As I said, the quality is bad, but it is clearly visible that the CPU is unsocketed and soldered and only two eeproms are on it despite the fact that it is ROM 1.2. Kind of odd...

20200806_201801_1.jpg
This is indeed odd :think: what do the date codes at the bottom of the board show? (little squares with dots and boxed number)

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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by bnz99 »

This one is a little better though it does not show the eeproms fully:
20201120_112028.jpg
So I guess it is revision E from 1990?


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by Rara »

bnz99 wrote: Fri Nov 20, 2020 11:22 am This one is a little better though it does not show the eeproms fully:

20201120_112028.jpg

So I guess it is revision E from 1990?
February 1990 going by the date codes, the cpu is an odd one though I have never seen this version before.


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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by shadowmask »

They switch to the SMD CPU version because it is the cheaper option.

This usually happens when they are happy that (most) of the bugs are out of the CPU's firmware so they get the CPUs manufactured with the code already burnt-in at the manufacturer. No socket needed and these CPUs are cheaper than the PLCC programmable ones.

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Re: SY77 DM1 board/firmware versions (with pictures)

Unread post by mike71 »

Mine is a ROM version 1.5 Mainboard rev. D and ROM version V 1.2. Has socketed CPU and soldered ROMS.

Probably revison E is different because it could accept both a socket and a soldered CPU.

Was a thinh in the '90, My 80386 made by Vorbis had a mainboard like this, with a soldered 80386 but clearly marked pads to mount a socket. The optional 80387 of course had a socket

Updated images with a macro on the ROM chips. I think that the codes on the chip could reveal what firmaware is burned in.
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