Re: HIgh Pitched Whine

Hi Tim

Thanks for the advice. Moving cards might be a way forward. Will give it a go.

On Thursday, June 11, 2015, Tim Conniff tconno@... [yamahacs80] <yamahacs80@...> wrote:

?

Hi Bob
?You bought a part from me a while back....
80% chance there's nothing wrong with the supply at all.?
I assume you've thoroughly investigated visual possibilities on the 2 offending voice cards, but
it's highly likely everything funky resides there.
?You MIGHT want to swap the location of a working card with one of the 2 bad ones, and see if the problem moves, because it could also be something external but related to that voice(s) giving this
?headache.??Probably 45 minutes of soldering/desoldering to verify. God knows the wiring can create nightmares on these....but at least you'd know more than you do now about the prob.
good luck
Tim

On Thursday, June 11, 2015 8:58 AM, "bob@... [yamahacs80]" <yamahacs80@...> wrote:

?

OK... so I'm going to build a power soak to try and pin this down. ie. whether it is actually the PSU or if it's something elsewhere causing the issue.

Measuring about 0.6A on the +15V, and 0.65A on the -15V... Does that sound about right?

Re: HIgh Pitched Whine

#4376

Hi Bob

?You bought a part from me a while back....

80% chance there's nothing wrong with the supply at all.?

I assume you've thoroughly investigated visual possibilities on the 2 offending voice cards, but

it's highly likely everything funky resides there.

?You MIGHT want to swap the location of a working card with one of the 2 bad ones, and see if the problem moves, because it could also be something external but related to that voice(s) giving this

?headache.??Probably 45 minutes of soldering/desoldering to verify. God knows the wiring can create nightmares on these....but at least you'd know more than you do now about the prob.

good luck

Tim

On Thursday, June 11, 2015 8:58 AM, "bob@... [yamahacs80]" wrote:

OK... so I'm going to build a power soak to try and pin this down. ie. whether it is actually the PSU or if it's something elsewhere causing the issue.

Measuring about 0.6A on the +15V, and 0.65A on the -15V... Does that sound about right?

Re: HIgh Pitched Whine

#4375

OK... so I'm going to build a power soak to try and pin this down. ie. whether it is actually the PSU or if it's something elsewhere causing the issue.

Measuring about 0.6A on the +15V, and 0.65A on the -15V... Does that sound about right?

HIgh Pitched Whine

#4374

Hi

Still having issues with this CS50 PSU.

I've got a horrible high pitched whine all over everything. If I turn the amps off, I can actually hear this noise emanating from the PSU.

If I put a probe on the lines, I've got oscillation on both the + and -15V lines. Much worse on the -15V line.

I've recapped it, changed all the transistors, and diodes (Apart from the rectifiers)
Changed the 4458, but no change.

What's really odd is that if I touch the anode of the -15V zener (Opamp supply) with a scope probe, it collapses the Opamp supply.

Also... If I remove voice cards 3 and 4 from the rack and the problem goes away... even though they're still connected to the power.

Any incite, or suggestions? most welcome... I've got to get this thing sorted in a couple of weeks, so a client can use it on a session. :-s

CS60 and Yamaha spares

#4373

All,

After many years of lurking I'm making my first post...

With all the seasons that life brings my grand plans to restore a CS60 (no legs or lid) came to nought and I have to dispose of it due to moving to a smaller house.

The unit has been in storage since the late 90's and when stored worked and stayed remarkably in tune.. there was some mechanical damage to the preset switch bank so that some of them didn't lock and the front panel had minor cosmetic damage...couple of fader caps missing too.

I'm?near Oxford?UK and would prefer to pass the project on to someone who will complete it.....or I will sell the cards etc to anyone who could use them.

Along the way I acquired a few "spares" from a D80 and have

Mini Keyboard

Key assigner VCO, VCF,?VCA and envelope?boards

If you would like any more info please contact me via the board (please copy ) as my yahoo?group login details were tagged to a previous?employers email address?and only get parts of conversations forwarded.

Cheers

Tim

Re: Proper LSI values on Kas Board-Sharing project

#4372

Hello Mike,

Actually i've been reading about -6.5v/+8.5v (1/0) process almost everywhere in the manuals, and precisely this is what pushed me to really check the KAS LSI's, ?when i realized my TR1-TR8 didnt follow those values (I have more -4v/+6v).

So, i checked the?26600 and 26700, and there again i couldnt find -6.5v/+8.5v values everywhere, instead

i got a few confusing values here and there:

YM26600

- Note terminals (Pins 7-19)= +2.3v(Note on) / -3.8v(Note off)

- U1-U5 (Pins 20-24)= +2.5v(Note on) / +8.4v(Note off)

- N1-N4 and B1-B3: Inconstant results...Probably need to read more about LSI functions first to get the logic

?-All other values seem to be ok

YM26700

-CH1 (Pin 38)= 1v (stuck from lowest C to highest C)

-N1-N4 and B1-B3: Inconstant results...same as above

?-All other values seem to be ok

KAS Board?

TR1-TR8= -4.3v(Note on)?/ 5.5v(Note off)

TR9= -3.7v

At least, the top octave (i guess U5) is responding something ;)

Great if it inspires you something to start with! :-)

Thank for the help,

Luca

Re: Proper LSI values on Kas Board-Sharing project

#4371

Thank you Crow, actually i did mention that one in my sources for collecting infos, but indeed i didnt go thru all the detailed explanations about the LSI's functions...It is true that i opted for a quicker approach like just listing values, but surely it's a bit more complex than just that.

Gonna go into it deeper tonight, and collect more infos for sure that way :-)

About those IG series circuits, did you manage to get what you hoped for?

best

Re: Proper LSI values on Kas Board-Sharing project

#4370

What is your objective here?? I've had a few of them fail on me.? The most common symptom of failure is the top octave not responding.?

-Mike

http://borishelectronics.com

Re: Proper LSI values on Kas Board-Sharing project

#4369

开云体育

? There is a complete analysis of the custom chips in the Yamaha CS Servicing Guide.? I used this book to work out IG series equivalent circuits a dozen or so years back.? It covers the YM parts too.? There was a pdf of it up somewhere....yeah, here:

Crow
/**/

On 3/1/2015 7:17 PM, gearfire01@... [yamahacs80] wrote:

Show quoted text

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.

Proper LSI values on Kas Board-Sharing project

#4368

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!

Pitch Bend Ribbon Specs

#4367

Hi all!

Can somebody tell me how the pitch ribbon works on the CS-80? I mean does it output variable resistance or how is it made. I would like to use one for a CS-80 related project. There are new ribbons like this:

?

They are variable potentiometers, is the ribbon for the CS-80 similar? Thanks for any light on this in advance! :)