Hi guys.....i am having Oberheim Matrix 6 on desk.......issue is that every tone is highly distorzed, eg when you press key you hear tone and ashh....but not lound as it should, every tone, every voice..... you have sample of it in mp3 so you can hear...
I did quick check, clock from CPU to voice board seems to go fine, as well da on voice board was replaced before, but as i can tell signals after D/A seems to be ok, as well dc after 4051. Output section is ok, i checked signal directly after CEM3396, even with output leg attached and still same.......
At end of sample is if you play something and suddenly remove control cable from voice board you can hear normal sound, distorzion gone......now, that could not directly put voice card out of problem because in that case voice board is left without any clock, so in case some 4051/4053 is bad there would be no clock on it and no problem.......
All controlls and display are fine, preset fine, memory also....even calibration and tunning is passed without any error.....also checked data and adress lines from mcu and all is ok, no lower level or no signal on them.......
Checked CV controlls to CEM3396 and is fine, when i moving for say resosnance in menu, i can see voltage on CEM3396 is going from 0 to 4V or so, as i am moving setting, voltages folows it, same for some other function like balance vca or so. Thing sounds to me like some MSB bits are missing, but since it's analogue......also, i put phones and listed to sound after LFO and 8254 dividers and tone is ok.
If someone has experiance or so, let me know......
mp3 sample:
https://drive.google.com/drive/folders/0Bz8-GluMkEK_WmkwY0t3bGxxYkk
I did quick check, clock from CPU to voice board seems to go fine, as well da on voice board was replaced before, but as i can tell signals after D/A seems to be ok, as well dc after 4051. Output section is ok, i checked signal directly after CEM3396, even with output leg attached and still same.......
At end of sample is if you play something and suddenly remove control cable from voice board you can hear normal sound, distorzion gone......now, that could not directly put voice card out of problem because in that case voice board is left without any clock, so in case some 4051/4053 is bad there would be no clock on it and no problem.......
All controlls and display are fine, preset fine, memory also....even calibration and tunning is passed without any error.....also checked data and adress lines from mcu and all is ok, no lower level or no signal on them.......
Checked CV controlls to CEM3396 and is fine, when i moving for say resosnance in menu, i can see voltage on CEM3396 is going from 0 to 4V or so, as i am moving setting, voltages folows it, same for some other function like balance vca or so. Thing sounds to me like some MSB bits are missing, but since it's analogue......also, i put phones and listed to sound after LFO and 8254 dividers and tone is ok.
If someone has experiance or so, let me know......
mp3 sample:
https://drive.google.com/drive/folders/0Bz8-GluMkEK_WmkwY0t3bGxxYkk
