It could have nothing to do with your problem, but I once repaired a CS-60
that had a similar sounding problem. The pitch didn't change much at all
across the keyboard. It turned out that one of the power supplies ( I
don't remember if it was the analog or digital supply had lost it's earth
ground reference. So depending on the currents flowing between the digital
and analog systems (like what pitches and octaves were being sounded) the
"loose" power supply just floated around. The failure point was at one of
the big star ground lugs; a thick solid wire had fractured. This problem
would show up when measuring the analog rail relative to the postive digital
rail and seeing if it's not what its supposed to be, and it changes
depending on what notes are sounding.. Good Luck!
Regards,
Kyle Jarger
----- Original Message -----
From: "Heath Finnie" <heathfinnie@...>
To: <yamahacs80@yahoogroups.com>
Sent: Saturday, December 27, 2008 11:20 AM
Subject: [yamahacs80] Re: stumped - no variation of pitch!!!
>I noticed that if I took TR29 out completely and fired it up, the pitch
>problem disappeared.
> (disappeared, although the ribbon and tuning pot still have no effect)
> Granted, it sounds
> like crap, but it is a start. I tried 3 different C458 transistors and
> whenever I put one in, the
> pitch problem comes BACK and it will be the same pitch across the
> keyboard.
>
> Heath
>
> --- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@...> wrote:
>>
>> I'm back at the CS-80 repair. I ended up removing TU from the KAS board
>> but before I
> was
>> getting 'nearly' the same pitch across the whole keybed, and the voltage
>> at TU was
>> 13.37v. I removed TU and the pitch totally changed on the keys. I was
>> getting much
> more
>> variation of pitch across the keybed, just octave issues. I replaced TU
>> back onto the KAS
>> board and the pitch stayed pretty much the same as this new way now. Here
>> is a clip of
> me
>> playing every key up the keybed:
>> http://www.heathfinnie.com/media/cs80issue.mp3
>>
>> The voltage at TU dropped some as well after removing it and the
>> resoldering it. It's now
>> at 10.37v and VR3 on the BA board has 0 effect on this voltage like it
>> should. I should
> also
>> note that the tuning knob and pitch ribbon still have no effect on the
>> pitch. I tried to do
>> the adjustment of the KAS board and here are the voltages I'm getting:
>>
>> TU: 10.37v (should be 4v)
>> Octave Ladder network - should be 125.0mv at Pin 13 on IC2 I'm
>> getting -4.10v
>> Voltage follower: Pin 6 IC3: Should be 125.0mv, I'm getting 2.55v
>> Note Ladder Network: Pin 38 IC2: Should be +132.4mv, I'm getting 2.55v
>>
>> On the BA board I've replaced IC1, 2, 3 and 4. TR29 and both Fets. I
>> highly doubt the
>> problem is on the KAS board as I replaced it entirely from another one
>> and the problem
>> was exactly the same.
>>
>> Thanks!
>>
>> --- In yamahacs80@yahoogroups.com, "willgregori" <will.gregory@> wrote:
>> >
>> > Had the same problem, on my cs80 TR29 was a broken on the BA board,
>> >
>> > good luck
>> >
>> > --- In yamahacs80@yahoogroups.com, "Heath Finnie" <heathfinnie@>
>> > wrote:
>> > >
>> > > This is a big question here. The CS-80 I'm working on will barely
>> > change pitch all the way up
>> > > the keyboard now. Some keys will play a little lower but not much.
>> > Now here are the
>> > > symptoms:
>> > >
>> > > I replaced most all the IC's on the sub board. I replaced the
>> > entire KAS board with a working
>> > > one. Problem does not change.
>> > >
>> > > The pitch ribbon is having no effect on pitch. Neither is the pitch
>> > knob.
>> > >
>> > > The channel 2 detune IS working as is the footing sliders.
>> > >
>> > > Ring modulator is working, sub oscillator is working and so is all
>> > the waveforms.
>> > >
>> > > Any of the tech guys able to help?
>> > >
>> > > Thanks!
>> > >
>> >
>>
>
>
>
>
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