SY99 - System reset? / horrible distorted noise in outputs.

The Yamaha SY99 is a synthesiser combining frequency modulation synthesis (branded as Advanced FM) and sample-based synthesis (branded as Advanced Wave Memory 2) and the direct successor to Yamaha's SY77/TG77

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Lampmeister
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SY99 - System reset? / horrible distorted noise in outputs.

Unread post by Lampmeister » Mon Mar 17, 2008 2:02 pm

Hi everyone,
I got myself an SY99 a few months ago, it's fab but has developed a problem, a serious one too. All the sounds have suddenly become horribly distorted through all the outputs, headphones included. The distortion still follows the amp envelope of the sound that is selected. I'm starting from the easiest thing to try first which to me would be to see if there is a system reset command or similar, I've trawled through the manual but can't find such a thing at the moment. If anyone knows where I can find a system reset command then I'd be very grateful for any information. Any other suggestions or accounts of similar experiences would be very helpful too.

Many thanks,

David.
Last edited by Lampmeister on Mon Mar 17, 2008 10:34 pm, edited 1 time in total.
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Clyde
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Unread post by Clyde » Mon Mar 17, 2008 2:26 pm

Hi David,
Welcome to the Forums! Here is the Yamaha SY99 reset info from the Yamaha Knowledgebase:
"Knowledge Keyboards and Digital Instruments Professional Synthesizers, Workstations and Tone Modules Synthesizers
SY99

SY99 Factory Reset procedure

WARNING: All user stored data will be deleted. If the current settings and data are not expendable, create a backup before executing the Factory Reset.

Reference: Owner's Manual, p.266-274.

1) Turn on the power.

2) While pressing the [VOICE] button, press and hold the [BANK D] button, then the [8] button. The SY99 will run the INITIAL TEST routine and display the Test Program Menu.

3) Release all held buttons and press the [COPY] button. The SY99 will execute Test 48 'Factory Settings', automatically exit the Test Mode, and then return to Play Mode."

Make sure you do a "Save All" backup disk prior to doing a reset.
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Lampmeister
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Unread post by Lampmeister » Mon Mar 17, 2008 10:32 pm

Hi Clyde,

That's great, much appreciated! I couldn't find that in my pdf manual for the life of me!

Unfortunately it hasn't solved the problem. I'll keep poking around with it and see what turns up. In the meantime if anyone has relevant advice/experience/suggestions then I'd much appreciate it!

Cheers,

David.
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Clyde
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Unread post by Clyde » Tue Mar 18, 2008 1:04 am

Since a reset did not solve the issue, it is starting to sound more like a problem in the output circuit board. One last issue you may want to check (since there is really no cost involved) is if the internal battery is up to snuff, any error message telling you to change battery, etc.? I don't think that is your issue, but it never hurts to check as low battery voltage can make many strange things happen. I would look for bad solder joints on the output or leaking capacitors that are bad. If you are not handy at electronics repairs then I would take it to an authorized service center. Also, check over in the DX forum, I think someone there had a similar problem with a DX7 not very long ago.
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Unread post by Fozzer » Tue Mar 18, 2008 10:12 am

After having a peek at my Keyfax 4 Synthesizer Guide last night, I notice that the SY99 was first released in 1991, so that would make it getting on for 18 years old.

The internal Lithium Battery life is around 20 years, and I have experienced all sorts of "Strange Happenings" when the batteries have been running low on all my 1980's DX Synthesizers. (I have had to replace all their batteries now!).

As Clive mentioned, there should be a warning come up on the display screen if the Battery is getting "Low".

Apart from that, again as Clive mentioned, It looks like a nasty case of internal "Hardware Failure"...quite unusual, I would have thought!... :cry: ...!

Best of luck...;)...!

Paul.... 8) ...!
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Unread post by Lampmeister » Tue Mar 18, 2008 12:37 pm

Cheers chaps, much appreciated.

I'll have a poke around with it over the next few days and see what comes to light.

There's no battery warnings, either upon start-up or when doing the re-initialisation routine. It also doesn't sound like a dry solder joint.

Just to correct my first post, the distortion starts when any key is played and is continuous, but then when other keys are played they new keys follow the amp env of the particular sound. Strange.

Cheers!

David.
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Clyde
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Unread post by Clyde » Tue Mar 18, 2008 1:22 pm

http://www.yamahaforums.co.uk/modules.p ... pic&t=1829

The link above is the DX7 thread I was talking about in case you did not find it. Besides "dry" solder joints I think bad capacitors are the most common problem, you can usually spot them as the appear to be leaking. And I have to mention again, even with no battery error messages, low battery voltage can cause all kinds of strange issues. I changed one recently on my SY99 using a CR2032 with the solder tabs pre-attached, cost was about $3.50 US for the battery.
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Unread post by Lampmeister » Wed Mar 19, 2008 1:35 pm

Cheers Clyde, much appreciated indeed!

I'll exhaust all my options over the next week or two as time allows efore taking it to my local friendly and knowledgeable (but not cheap) electro-techy man with a solder gun.

Regards,

David.
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Unread post by CS01Fanatic » Mon Jun 01, 2009 11:32 pm

I too have experienced (& still do on occasion) this distortion on powering up, but I have found that turning the machine off for a few seconds, then back on usually gets rid of it first time (only rarely have I had to do it twice).

I bought mine second hand & it has always done this, but once it's playing fine, it doesn't happen again unless it's turned off. I often wondered what's causing it but as it's only a minor issue at the moment, I'll wait until it becomes a major issue before I put it in for repair.
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Unread post by Clyde » Tue Jun 02, 2009 12:15 am

CS01Fanatic wrote:I too have experienced (& still do on occasion) this distortion on powering up, but I have found that turning the machine off for a few seconds, then back on usually gets rid of it first time (only rarely have I had to do it twice).

I bought mine second hand & it has always done this, but once it's playing fine, it doesn't happen again unless it's turned off. I often wondered what's causing it but as it's only a minor issue at the moment, I'll wait until it becomes a major issue before I put it in for repair.
Every once in a while I'll get some slight distortion in the sound with my SY77 that I've had since 1989, it's done so since new, re-booting does seem to clear it. I always attributed it to having the very first OS as mine came out of the first shipment air freighted to the US, tried to upgrade the ROMs a couple of years ago and was able to purchase them from Yamaha, but since they were all different numbers than the originals and no one at Yamaha could tell me which one went where and what jumpers needed to be installed on which ICs, I finally sent them back and got a refund. It does not get any distortion often enough for it to be a real problem for me, funny though, the used SY99 I bought a few years ago has never done so, it has the last (1.57) OS ever written for the SY99.
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Unread post by ctirad » Wed Jun 10, 2009 7:34 am

Hello. Did you fixed it, David? I have the same problem with my SY99. The distrosion has an "digital type" character, so probably there is something wrong around DAC/Demultiplexer.

Please, could anyone provide a service manual and/or schematics for SY99? The DAC stage part should be enough. That would help a lot. Thanks.
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Unread post by Clyde » Wed Jun 10, 2009 12:59 pm

Hi ctirad,
Welcome to the Forums! Send me a PM with your email address and I'll see if I can help you out.
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Unread post by YamYam » Tue Jun 16, 2009 6:17 pm

Hi,

shure that it's the output section? I have the same problems sometimes. It is only when the Sy was switched off for a longer time. Then after switching on I had the same distorted sound. But when I pressed the "Effect Bypass" button, the dry signal was clear. So maybe there is something wrong with the effect section?

After switching the synth off and on again the sound was ok again and the Sy did his job (with active effects).

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Unread post by ctirad » Thu Jul 02, 2009 7:48 pm

Hi YamYam,

in my case the distortion is still there with or without EQ enabled. It's also independent of signal source (AFM/AWM), routing setup, etc..

Clyde provided me some very useful info and diagrams, so I checked the PSU, power and signal stage around DAC and replaced some caps. Unfortunatelly it dindn't helped at all :( Next I'm going to bring my SY99 to my friend's work and check it again with oscilloscope for possible oscillations and so, which I cannot see on multimeter.

Ctirad
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Unread post by b3groover » Thu Jul 02, 2009 8:09 pm

This thread brings up an interesting point: What are the last OS versions for the SY77 and SY99 and do we know what problems they addressed?
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