Hello CS80 users,
Probably as most CS80 owners, i am aware that the most critical parts in the beast are the 2 main LSI's (YM26600&Ym26700), as their failure could quickly become problematic, since they are Yamaha proprietary and for this reason, hard to find/replace.And because they are the brain of the system, i guess it's important to rely on them in first place, before doing any other work/check further in the synth.
That's why i decided to check mine, and for this purpose i focused on the values that i should expect on their respective 40pins.For this i collected infos from the CS Series servicing guide, CS80 service manual, and CS80 tuning&adjustment procedure, but unfortunately without concluding to a definitive and complete list of 'proper values'.Of course i also completed that list with some tangible results collected from my own CS80, but i prefered to leave a question mark in those places where my own CS80 results seemed hazardous.
Maybe some of you could advice me in the process? My intend is to create ultimately a visual map of the LSI's of the most important boards, starting with the KAS for now.The idea is to share all results in this forum for everybody's convenience, so any help is welcome!
So, this is what i could find (question marks stand for unknown values, and in parenthesis are my own CS80 values, filling missing infos from the manuals):
1) LSI YM26600:
-VSS (Pin#1)= +8.5v
-Master Clock (Pin#2)= 94Khz (~5khz)
-SC (Pin#3)= 1/9 of 94Khz= 10.8Khz
-SC8 (Pin#4)= 1/8 of 10.4Khz= 1.35 Khz
-IC (Pin#5)= ?
-VDD (Pin#6)= -6.5v
-Note terminals (Pin#7-19)= ?
-U1-U5 (Pin #20-25) = ?
-N1-N4 (Pin #25-28) = ?
-B1-B3 (Pin #29-31)= ?
-K01-K08 (Pin #32-39)= +8.5v/-6.5v (Note off/Note on)
-MODE (Pin #40)= -6.5v/+8.5v (8 sounds/7 sounds)
2) LSI YM26700:
-VSS (Pin#1)= +8.5v
-SC8 (Pin#2)= 1.35 Khz (=Pin#4 YM26600)
-PORT (Pin#3)= -6.5v/+8.5v (PN3-VR2 short/long)
-PC (Pin#4)= ?
-N1-N4 (Pin#5-8)= ?
-B1-B3 (Pin#9-11)= ?
-Pin#12= 10.4Khz
[-Pin#13=125mv
-Pin#14= 250mv
-Pin#15= 500mv
-Pin#16= 1v
-Pin#17= 2v
-Pin#18= 4V
-Pin#19-30 (C0/C5)=190mv/1.97v-202mv/2.1v-214mv/2.22v-227mv/2.35v-240mv/2.49v-255m/2.64v-270mv/2.80v-286mv/2.97v-303mv/3.14v-321mv/3.33v-340mv/3.53v-361mv/3.75v]
-Pin#31-38= ?
-pin#39= -6.5v
-Pin#40= 94Khz
Thank you for your help!