SY77 booting in a loop

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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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Dec 22, 2018 6:44 am

Cool, found it.

That makes it really easy to clone the microprocessor.

Anthony.
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Re: SY77 booting in a loop

Unread post by Rara » Sat Dec 22, 2018 9:50 am

Don't thank me, Thank the person who originally uploaded it here ;-)

Rara 0-)
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Re: SY77 booting in a loop

Unread post by Horizonsound » Fri Dec 28, 2018 9:49 pm

I'm still working through this issue on my original DM1.
This question may be in hope, but does anyone have any idea as to how the memory works / what is allocated to each address, or is it simply random?
My issue with the keyboard freezing after a short amount of time, i was thinking, may be due to a bad sector in the RAM, and once it is accessed, the system freezes. I feel it's either that or the CPU.

Been spending the last week learning up on computer architecture again. The physical design of SY77 is fairly simple. A few devices hanging off shared data busses, accessed by addresses, being driven by a CPU.

Anthony.
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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Dec 29, 2018 1:31 am

A little more progress. I've found that while the keyboard works fine for the first half minute, before it melts down, address bus A12 shows a constant pattern on the scope, mostly a low state. As the keyboard approaches the freeze, A12 gradually trends towards a high state. This is only true for address bus A12, and every other address bus does not show this type of pattern or change. It's the only data or address bus that seems to show any signs of problem, prior to freezing. A12 is connected to the SRAM, ROM A-D, and plays a part in a few other functions (M3FM).

Anthony.
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Re: SY77 booting in a loop

Unread post by Rara » Sat Dec 29, 2018 8:05 am

interesting, i wonder if this is actually a common fault as there is a lot of dead 77's about at the moment.
what your describing still sounds like mine except for the reboot.

I won my self another auction, this time it was ebay :-(
I'm fairly confident that other board is dead.
I won for myself DM1 and DM2 boards. However there are faults in this DM1 as well.
this type is the H8 cpu with 2 roms in 2 of the 4 sockets
Apparently these boards do work but their functions appear to be limited and there's also apparently only one sound.
for which I'm sure, has something to do with the muppet who peeled off the protective tape from the eprom.
(and a no doubt dead battery)

Does this type of board run the same firmware version as the previous? or would anyone happen to know the version this particular
board runs, so that I can re-burn the chip, if that version can be found.

Rara 0-)

Edit: a few weeks later: no need to worry about what the firmware is, the DM1 in this photo is as dead as my original.
(Y) well done to me :clap: :/:
DM1no.3.JPG
DM1no.3.JPG (51.24 KiB) Viewed 675 times
Last edited by Rara on Sun Jan 20, 2019 9:56 am, edited 1 time in total.
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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Dec 29, 2018 9:15 am

Hey Rara,

I believe you must have outbid me by $1 on that auction!!!!

The reason for wanting those, was to get a hold of the H8/532 socketed CPU, and switch it out for mine to see if that is the problem.
Perhaps we could make a deal if you don't need it or could lend it???
If it turn out to be the source of the problem, then I'm looking to get all the gear to burn a replacement clone.

FYI my socketed H8 chip has "XG944 iD" sticker-ed on to it.

If i end up getting the all the above gear, I could clone you a new IC151. That's the sequencer EPROM I saw that had the sticker peeled off in those photos.

My SRAM has only just been shipped from utsource via HK post. A bit annoyed as I paid a premium for it to be sent Fedex.

Anthony.
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Re: SY77 booting in a loop

Unread post by Rara » Sat Dec 29, 2018 10:39 am

:o The world seems small sometimes, the internet makes it smaller still ....

I can lend you the CPU no problem, happy to help. After/if the board checks out. I was thinking either re-burn that eprom,
or pull one from one of the other boards,... it'll be two weeks at least before its here.
I cant say how long it'll be until i see results of this particular board. I don't have my SY77 with me,
my tech has it. (due to a lack of room to work on something this big and complex.)

when i find out what the results are I'll be sure to let you know.

Paying a premium for a slack service, I hope the seller has a darn good excuse. my last board was
held up mostly due to post here.

Rara 0-)
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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Jan 12, 2019 12:24 am

OK, it's been a while as I have been waiting for parts to roll in.

I decided to buy a Minipro (XGecu pro) programmer. After taking 3 hours to make the PLCC84 to DIP28 adaptor (no easy task), I loaded my H8532 and extracted the data, and saved it.

Then, in a massive leap of faith, went to re programm it with the BIN file that was on the sector101 site.
It crashed when trying to write to address 0x00 0285. Every time I tried.

Looking deeper in to the BIN file I noticed that the value for this address on the sector101 file was D6 whereas when I extracted the data from my H8532, it was E2. This address data was the only value different as far as I could find.

So... I suspect that my H8532 has a bad address in it, as highlighted when trying to program it.

Luckily I have purchased a new H8532 which should arrive any day now....

Anthony.
Yamaha : DX7, RX5, SY35, SY77, REV7, PMC1, SPX900, FX500
Roland : XP50, JX-3P, JV80, JP-06, D-05, TR-09
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Re: SY77 booting in a loop

Unread post by shadowmask » Sat Jan 12, 2019 8:30 am

Then, in a massive leap of faith, went to re programm it with the BIN file that was on the sector101 site.
It crashed when trying to write to address 0x00 0285. Every time I tried.
The H8-532 CPU is a one-shot programmable device, it cannot be reprogrammed successfully as there is no way to erase it.

Brian
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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Jan 12, 2019 11:59 am

Is this a PROM seriously???
So ive got one chance to get it right!

Anthony.
Yamaha : DX7, RX5, SY35, SY77, REV7, PMC1, SPX900, FX500
Roland : XP50, JX-3P, JV80, JP-06, D-05, TR-09
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Re: SY77 booting in a loop

Unread post by Miks » Sat Jan 12, 2019 1:36 pm

Horizonsound wrote:
Sat Jan 12, 2019 11:59 am
Is this a PROM seriously???
Not quite - it IS (technically) an eprom, but since the housing has no 'quarz-glass window' its not possible to erase that eprom part using an UV lamp. Back in the days there have been H8-532 CPUs with such a window - which allowed to erase those CPUs...
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Re: SY77 booting in a loop

Unread post by EB5AGV » Sat Jan 12, 2019 1:45 pm

Miks wrote:
Sat Jan 12, 2019 1:36 pm
Horizonsound wrote:
Sat Jan 12, 2019 11:59 am
Is this a PROM seriously???
Not quite - it IS (technically) an eprom, but since the housing has no 'quarz-glass window' its not possible to erase that eprom part using an UV lamp. Back in the days there have been H8-532 CPUs with such a window - which allowed to erase those CPUs...
This takes me back to my first work years, back in 90s... I developed firmware for embedded systems and had two types of CPUs. For prototyping, ceramic glass-window ones. But then, as a cost reduction for production, plastic one-time programming (OTP) ones. Of course, sometimes things didn't work as expected when the system was already in production... so the CPUs were scrapped :oops:

Those were the times, when a 32kB EPROM was enough to hold the full software! :lol:

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Re: SY77 booting in a loop

Unread post by Rara » Sat Jan 12, 2019 2:17 pm

Horizonsound wrote:
Sat Jan 12, 2019 12:24 am
OK, it's been a while as I have been waiting for parts to roll in.

I decided to buy a Minipro (XGecu pro) programmer. After taking 3 hours to make the PLCC84 to DIP28 adaptor (no easy task), I loaded my H8532 and extracted the data, and saved it.

Then, in a massive leap of faith, went to re programm it with the BIN file that was on the sector101 site.
It crashed when trying to write to address 0x00 0285. Every time I tried.

Looking deeper in to the BIN file I noticed that the value for this address on the sector101 file was D6 whereas when I extracted the data from my H8532, it was E2. This address data was the only value different as far as I could find.

So... I suspect that my H8532 has a bad address in it, as highlighted when trying to program it.

Luckily I have purchased a new H8532 which should arrive any day now....

Anthony.
Is there a difference in the code of the two cpus because the firmware downloaded came from a board with 4 eproms (5 with seq rom),
whereas the board the the stickered cpu is only addressing 2 roms (If that's the same version board your working on)?

Rara 0-)
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Re: SY77 booting in a loop

Unread post by Horizonsound » Sat Jan 12, 2019 11:05 pm

Well that might make some sense then. As the programmer thinks it is writing away, it hits that address location and fails upon verification, as the address value was not actually updated.
It might be a very slight difference in firmware revision.

Still, I can't believe the use of a OTP eprom even in 1990 to save money.

I wonder if there is an eeprom equivalent it could be switched for. Probably not an easy task.

Anthony.
Yamaha : DX7, RX5, SY35, SY77, REV7, PMC1, SPX900, FX500
Roland : XP50, JX-3P, JV80, JP-06, D-05, TR-09
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Re: SY77 booting in a loop

Unread post by Rara » Sun Jan 13, 2019 4:38 am

That's what I thought, ..... The same is of the SY85, every revision to the motherboard had a revision to the firmware,
not a simple case of upgrade the 1.1 firmware to 1.34, to do that you have to replace the whole board.
Which is what got me thinking earlier about this board off ebay, the firmware for that might be different for the
hardware change.

Rara 0-)

Edit: as far as i know, there is no pin compatible replacement for a H8/532.
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