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Poly 800 seems to works, no sound or strange sounds at very low volume

Poly 800 seems to works, no sound or strange sounds at very low volume

2014-09-21 by lushox@...

I have purchased 2nd hand a Poly 800 reversed keys edition and it was working couple of times. Today sudenly when powering the unit the display was flickering. At the moment of pressing the keys, the numbers on the display were flickering, getting a little bit darker like loosing power. No sound came out.

It seemed that the poly 800 was reseting itself. I have swithced on/off the unit a couple of times. After that strange behaviour the display is now working, also when I trying to access the sound parameters and inputing data all seems to work. However there is no sound! On some presets I'm obtaining strange sounds at a very low level. I tried also to change OSC volume and EG settings however nothing changed. I have read that maybe the unit must be reprogrammed, but I don't think this is the case. Or is it?

What else is wrong? Is it maybe the PSU?


Thank you for your answers.


Re: [korgpolyex] Poly 800 seems to works, no sound or strange sounds at very low volume

2014-09-21 by gordon@...

On Sun, Sep 21, 2014 at 01:25:42PM -0700, lushox@... [korgpolyex] wrote:
> I have purchased 2nd hand a Poly 800 reversed keys edition and it was working couple of times. Today sudenly when powering the unit the display was flickering. At the moment of pressing the keys, the numbers on the display were flickering, getting a little bit darker like loosing power. No sound came out.
> It seemed that the poly 800 was reseting itself. I have swithced on/off the unit a couple of times. After that strange behaviour the display is now working, also when I trying to access the sound parameters and inputing data all seems to work. However there is no sound! On some presets I'm obtaining strange sounds at a very low level. I tried also to change OSC volume and EG settings however nothing changed. I have read that maybe the unit must be reprogrammed, but I don't think this is the case. Or is it?
> What else is wrong? Is it maybe the PSU?

The first bit sounds like it's the power supply. Either your batteries or flat or the PSU isn't up to the job. You need 9V at *at least* 1A for it to work properly (think the factory PSU is supposed to be 800mA but that's a bit weedy, and gets hot).

It sounds like the patches are scrambled. Now you get to enter some new ones!

--
Gordonjcp MM0YEQ

Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2014-10-31 by lushox@...

[SOLVED] The problem was the battery leakage. Because of that, the patches and sequencer memory was lost. The Poly 800 was making strange sounds or almost no sound at all.
The same problem was described in this youtube video:
Korg Poly-800 problems...
Korg Poly-800 problems...
edit: the problem has been fixed by simply re-prgramming the synth. thanks for the help :) i just bought a Korg Poly-800 as-is at a thrift store, got it home...
View on www.youtube.com
Preview by Yahoo

 


SOLUTION: I've changed all the batteries (6 x 1.5V). And reprogrammed the memory by loading into the Poly 800 the default or factory patches from the wave file which can be found here:

Hope this would be helpful,

Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2016-12-10 by temsed7@...

Good evening, everyone,

I'm writing my first message on this great forum, so that maybe someone could help me.
I saw this conversation while I was looking for a solution for my own poly800 MKII... I have some skills in soldering but I have been looking for a solution alone for too long...
So, when I bought it, it worked well, except the switch, working even when I didn't want it to. I opened the synth, and fixed this by soldering. Then, I reloaded all the patches, and I thought everything would be alright. I played it for some days...
However, some days later, something went wrong, as all my patches were kind of "destroyed", and I couldn't get any "normal" sound out of it... I can just hear strange and weak sounds, and sometimes even no sound...

Let me tell you what I've done so far:

- Reloading the patches several times.
- Checking the battery saving the patches (this one is OK).
- Looking for leaking or broken parts/components.

I do not know what to do, and I'm really sad because this synth was a true source of inspiration for me...

If anyone could give me a hand, that would be absolutely great and helpful!

Best regards,

Gloubi

Re: [korgpolyex] Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2016-12-10 by Alex Drinkwater

The Poly-800 Mk.I has an issue where the MIDI buffer would overrun when too much MIDI data was sent to the synth, overwriting patch memory with random data.

I wasn't aware this also happened on the Mk.2, but it sounds like it may, from your description.

a|x

On 10 Dec 2016, at 17:23, temsed7@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:

Good evening, everyone,

I'm writing my first message on this great forum, so that maybe someone could help me.
I saw this conversation while I was looking for a solution for my own poly800 MKII... I have some skills in soldering but I have been looking for a solution alone for too long...
So, when I bought it, it worked well, except the switch, working even when I didn't want it to. I opened the synth, and fixed this by soldering. Then, I reloaded all the patches, and I thought everything would be alright. I played it for some days...
However, some days later, something went wrong, as all my patches were kind of "destroyed", and I couldn't get any "normal" sound out of it... I can just hear strange and weak sounds, and sometimes even no sound...

Let me tell you what I've done so far:

- Reloading the patches several times.
- Checking the battery saving the patches (this one is OK).
- Looking for leaking or broken parts/components.

I do not know what to do, and I'm really sad because this synth was a true source of inspiration for me...

If anyone could give me a hand, that would be absolutely great and helpful!

Best regards,

Gloubi

Re: [korgpolyex] Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2016-12-11 by Steve Daniels

Gloubi,
I believe the issue is with the static RAM (SRAM) chip. It's a $5 part. You can't get it from Korg anymore, but other people still sell them new.

I had something similar happen to me. After ruling out the battery (but replacing it anyway), the tech replaced that chip, and I haven't had that problem since. 

It's the first IC chip in the row, and it's a quick, cheap fix.

Steve

On Saturday, December 10, 2016, 12:23 PM, temsed7@... [korgpolyex] <korgpolyex@yahoogroups.com> wrote:

 

Good evening, everyone,


I'm writing my first message on this great forum, so that maybe someone could help me.
I saw this conversation while I was looking for a solution for my own poly800 MKII... I have some skills in soldering but I have been looking for a solution alone for too long...
So, when I bought it, it worked well, except the switch, working even when I didn't want it to. I opened the synth, and fixed this by soldering. Then, I reloaded all the patches, and I thought everything would be alright. I played it for some days...
However, some days later, something went wrong, as all my patches were kind of "destroyed", and I couldn't get any "normal" sound out of it... I can just hear strange and weak sounds, and sometimes even no sound...

Let me tell you what I've done so far:

- Reloading the patches several times.
- Checking the battery saving the patches (this one is OK).
- Looking for leaking or broken parts/components.

I do not know what to do, and I'm really sad because this synth was a true source of inspiration for me...

If anyone could give me a hand, that would be absolutely great and helpful!

Best regards,

Gloubi

Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2016-12-11 by temsed7@...

Dear Steve,

I do thank you for your answer! I have spent my whole morning looking for that component, and actually, it seems this comes from Hitachi... However, 4 different chips could be the one you are talking about.
These are:

HD-U050 BP 
HD-14051 BP 
HD-14053BP 
HD-63B50P

I found this in the service manual, but I don't know which one is the right one to replace... I suppose it's the HD14053BP as it's closer to the midi implementation. Moreover, there is one more mistery... On the chip inside my synth, something is written right under the name of the chip (HD1 4053BP) : 5K4T. I do not know what that means and this is quite annoying, indeed, because on some new 4053BP chips I can buy on the net, all of those hav different marks from this one! There are a lot of those, but no sign of the "5K4T" mark... This is strange.

Would you mind telling me what to do?

Thank you in advance,

Gloubi

Re: [korgpolyex] Re: Poly 800 seems to works, no sound or strange sounds at very low volume

2016-12-11 by Michael Hawkins

If the Poly 800 works in every way except for sound then I don't think it is the RAM chip.

Let's try some more detailed questions first.

Are you able to program patches manually?
Do the parameters in the patches stay saved if you select another patch and come back to that saved patch?
Do all buttons work?
Do you see MIDI OUT note on and note off events when you press keys?
Do you see MIDI OUT program change messages when you change patches on Poly?
Do you see MIDI OUT CC messages when you move the joystick up and down, left and right?
With your best detailed description, what sound comes out of the Poly when you press a key AND what happens to the sound after you release the note?
After you release the note, do you hear a 'hiss' go away almost completely after some time passes?
Do you get a "Good" message when you reload patches from tape?
Are you able to program the step sequencer?

/Mike


From: "temsed7@... [korgpolyex]" <korgpolyex@yahoogroups.com>
To: korgpolyex@yahoogroups.com
Sent: Sunday, December 11, 2016 7:49 AM
Subject: [korgpolyex] Re: Poly 800 seems to works, no sound or strange sounds at very low volume

 
Dear Steve,

I do thank you for your answer! I have spent my whole morning looking for that component, and actually, it seems this comes from Hitachi... However, 4 different chips could be the one you are talking about.
These are:

HD-U050 BP 
HD-14051 BP 
HD-14053BP 
HD-63B50P

I found this in the service manual, but I don't know which one is the right one to replace... I suppose it's the HD14053BP as it's closer to the midi implementation. Moreover, there is one more mistery... On the chip inside my synth, something is written right under the name of the chip (HD1 4053BP) : 5K4T. I do not know what that means and this is quite annoying, indeed, because on some new 4053BP chips I can buy on the net, all of those hav different marks from this one! There are a lot of those, but no sign of the "5K4T" mark... This is strange.

Would you mind telling me what to do?

Thank you in advance,

Gloubi