OBERHEIM SYNTH group photo

Yahoo Groups archive

OBERHEIM SYNTH

Index last updated: 2026-04-28 23:39 UTC

Thread

Pitch Problems on Matrix1000 with working chips (audio attached)

Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-12 by Andreas Östling

Hi, I've been trying to figure out the problems with my Matrix 1000. First of all I did the chip test and realized that three chips only had one voice, so I exchanged them for new ones. Now all chips are supposed to work. I have done the calibration tests and the two other ";zeroing"-procedures in the test menu, but still get an annoying pitch problem (mp3 audio attached). I've recapped some of the unit, but it didn't help, the battery is changed as well (although I hardly think that could have anything to do with the pitch problem).

So in the attached mp3 I only trigger one note, but as you can see the pitch changes, after that I trigger an arppegio holding down _one_ note so you can see how the pitch "glides" from one place to another. Please help! :D I am yet to acctually play this resently bought synth ;(

Attachments

Re: [oberheim] Pitch Problems on Matrix1000 with working chips (audio attached) [1 Attachment]

2013-08-12 by Narfman96 - Narfland Studio

Have you tried the individual voice chip test so you can tell if one specific voice is drifting. I hear one out the six is off. The .0033uf capacitors on pins 4 and 8 of the CEM3396 voice chips control the frequency for each DCO input by timing the digital pulses from the 82C54 pulse generators. These timing caps can cause drift. By swapping the voice chips around you should be able to tell if the problem is another voice chip or the support circuitry. A scope may help to find the drift. Each timing cap should have a sawtooth waveform as the pulse goes from high to low. The frequency should be the same for all of these inputs as long as the same note is being played ex. A440. You're not using a noise patch so you can probably eliminate the noise inputs You could check and see if the noise inputs do this also.  
 
Good luck and let us know what you find. Probably somebody here in the group has been through these circuits with a scope. Personally I haven't but I can usually read the docs and understand what should be there.
Show quoted textHide quoted text
>________________________________
> From: Andreas Östling <andreas85@...>
>To: oberheim@yahoogroups.com 
>Sent: Monday, August 12, 2013 5:48 AM
>Subject: [oberheim] Pitch Problems on Matrix1000 with working chips (audio attached) [1 Attachment]
>  
> 
>   
> 
> 
>[Attachment(s) from =?ISO-8859-1?Q?Andreas_=D6stling?= included below]  
>Hi, I've been trying to figure out the problems with my Matrix 1000. First of all I did the chip test and realized that three chips only had one voice, so I exchanged them for new ones. Now all chips are supposed to work. I have done the calibration tests and the two other "zeroing"-procedures in the test menu, but still get an annoying pitch problem (mp3 audio attached). I've recapped some of the unit, but it didn't help, the battery is changed as well (although I hardly think that could have anything to do with the pitch problem).
>
>
>So in the attached mp3 I only trigger one note, but as you can see the pitch changes, after that I trigger an arppegio holding down _one_ note so you can see how the pitch "glides" from one place to another. Please help! :D I am yet to acctually play this resently bought synth ;(    
>

Attachments

Re: Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-12 by Andreas Östling

That is really useful info you provided there!
Yes I've tried to use the voice chip test... (ext funct -> 7 -> enter -> enter (while "0" on display)) and then hit a note 6 times to run through the voices. I have the pitch error on all the voices... But then I did a Calibration, and after that an initialization and now the pitch problem is gone. It seems as if I have to redo it now and then (unreasonably often in my opinion). Is the calibration etc saved in memory and disappears if there is a problem with the battery? But the factory presets 200-> etc seem intact so shouldn't they disappear aswell if there is some problem with the battery? What could cause it to go back to being un-calibrated so quickly?

Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-12 by Narfman96 - Narfland Studio

The battery backup remembers the calibration what is the battery voltage? If the battery is low or the memory has a problem the calibration will be lost. There could be an issue with the power supply that might affect the digital timing but the chance is remote. Have you verified the DC voltages and the AC ripple present on these lines? The 000 to 199 user presets are not erased if you do a reset and calibration. If they remain intact and the calibration keeps losing it then I would suspect the paging memory control is having issues with the saved calibration data. This could be an SRAM or addresss bit issue.
Show quoted textHide quoted text
>________________________________
> From: Andreas Östling <andreas85@...>
>To: oberheim@yahoogroups.com 
>Sent: Monday, August 12, 2013 12:34 PM
>Subject: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)
>  
> 
>   
> 
>That is really useful info you provided there!
>Yes I've tried to use the voice chip test... (ext funct -> 7 -> enter -> enter (while "0" on display)) and then hit a note 6 times to run through the voices. I have the pitch error on all the voices... But then I did a Calibration, and after that an initialization and now the pitch problem is gone. It seems as if I have to redo it now and then (unreasonably often in my opinion). Is the calibration etc saved in memory and disappears if there is a problem with the battery? But the factory presets 200-> etc seem intact so shouldn't they disappear aswell if there is some problem with the battery? What could cause it to go back to being un-calibrated so quickly?    
>

Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-14 by Andreas Östling

I have now installed a battery holder (mine was a soldered-battery version which I tried to resolder a new battery to before, probably not the best solution), I've installed a new 3V CR2032 cell battery in my newly installed battery holder. I've done the initialization... and the pitch problem seems to be gone now! Even after a power down. I also found the original 0-200 soundbanks amongst the group files which is transferred and I guess the battery is working as long as these are intact? (I never had the 0-200 sounds before).

Obviously since I've had a lot of problems I'm still sceptical that everything will work out, but as for now :D I'm quite happy! Thanks for the great help and the patches. So as I understand it patches 0-200 are saved in RAM and require a battery or constant power supply to be remembered, and 201-1000 are patches saved in ROM, and are not dependent on constant power supply?

Again thanks.

Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-14 by Peter Mörck

Yes.
And congratulations :)
BR,
Peter
----- Original Message -----
Sent: Wednesday, August 14, 2013 4:56 PM
Subject: Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

I have now installed a battery holder (mine was a soldered-battery version which I tried to resolder a new battery to before, probably not the best solution), I've installed a new 3V CR2032 cell battery in my newly installed battery holder. I've done the ;initialization... and the pitch problem seems to be gone now! Even after a power down. I also found the original 0-200 soundbanks amongst the group files which is transferred and I guess the battery is working as long as these are intact? (I never had the 0-200 sounds before).

Obviously since I've had a lot of problems I'm still sceptical that everything will work out, but as for now :D I'm quite happy! Thanks for the great help and the patches. So as I understand it patches 0-200 are saved in RAM and require a battery or constant power supply to be remembered, and 201-1000 are patches saved in ROM, and are not dependent on constant power supply?

Again thanks.

Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

2013-08-14 by Peter Mörck

Or .. I believe it's 0-199 (inclusive) that reside in RAM and 200-999 (inclusive) that reside in EPROM :)
Show quoted textHide quoted text
----- Original Message -----
Sent: Wednesday, August 14, 2013 6:51 PM
Subject: Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

Yes.
And congratulations :)
BR,
Peter
----- Original Message -----
Sent: Wednesday, August 14, 2013 4:56 PM
Subject: Re: [oberheim] Re: Pitch Problems on Matrix1000 with working chips (audio attached)

I have now installed a battery holder (mine was a soldered-battery version which I tried to resolder a new battery to before, probably not the best solution), I've installed a new 3V CR2032 cell battery in my newly installed battery holder. I've done the initialization... and the pitch problem seems to be gone now! Even after a power down. I also found the original 0-200 soundbanks amongst the group files which is transferred and I guess the battery is working as long as these are intact? (I never had the 0-200 sounds before).

Obviously since I've had a lot of problems I'm still sceptical that everything will work out, but as for now :D I'm quite happy! Thanks for the great help and the patches. So as I understand it patches 0-200 are saved in RAM and require a battery or constant power supply to be remembered, and 201-1000 are patches saved in ROM, and are not dependent on constant power supply?

Again thanks.

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.