|
Hi Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz. Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside. PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts. Recapped the new PCB before I fitted it. I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc. The only difference is that originally it took a minute or so to manifest... now it manifests immediately. I can see the signal on all power lines. Any thoughts? B ?
|
are all 3 fuses intact?
?
---- On Thu, 17 Jul 2014 11:14:08 -0500 bob@... [yamahacs80] wrote ----
toggle quoted message
Show quoted text
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B
On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope. Tim
On Thursday, July 17, 2014 11:04 PM, "Bob Stewart bob@... [yamahacs80]"
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B
On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
dummy load may become pivotal in determining the source of the issue. Alternatively, of course, you could substitute another source of power if available, and i don't mean another cs50 supply, I mean ANY other capable source.? Given the whine's prevalence on the power lines, you might also want to disconnect the juice to the voice cards all at once and see if
it's still being heard, just to further rule out stuff. Btw, I have found a 150, just haven't had time to check it yet. good luck Tim
On Thursday, July 17, 2014 11:38 PM, "Bob Stewart bob@... [yamahacs80]" wrote:
?
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
Yeah, disconnecting stuff was going to be my next thing. I do have another CS50 , but the PSU has been modded and the connections are different. Otherwise that would've been the quickest solution. Will check out what I need for dummy loads as well. Not sure what the current consumption is on the different lines.?
Keep me posted about the 150
Cheers
Bob
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
dummy load may become pivotal in determining the source of the issue.
Alternatively, of course, you could substitute another source of power if available, and i don't mean another cs50 supply, I mean ANY other capable source.?
Given the whine's prevalence on the power lines, you might also want to disconnect the juice to the voice cards all at once and see if
it's still being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had time to check it yet.
good luck
Tim
?
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
I haven't worked on a 50 in 5 yrs, but I believe the US model draws? around .3A on the 15's, and slightly less on the 8.5/6.5 lines. for test purpose you could get by with that. ?In the UK, ?should approach half that, in theory. (for what that's worth):) Tim
On Friday, July 18, 2014 12:36 AM, "Bob Stewart bob@... [yamahacs80]" wrote:
?
Yeah, disconnecting stuff was going to be my next thing. I do have another CS50 , but the PSU has been modded and the connections are different. Otherwise that would've been the quickest solution. Will check out what I need for dummy loads as well. Not sure what the current consumption is on the different lines.?
Keep me posted about the 150
Cheers
Bob
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
dummy load may become pivotal in determining the source of the issue.
Alternatively, of course, you could substitute another source of power if available, and i don't mean another cs50 supply, I mean ANY other capable source.?
Given the whine's prevalence on the power lines, you might also want to disconnect the juice to the voice cards all at once and see if
it's still being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had time to check it yet.
good luck
Tim
?
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
made a blunder, supply currents won't be different at DC, only AC area. ?Time to get sleep, apparently. T
On Friday, July 18, 2014 1:01 AM, "Tim Conniff tconno@... [yamahacs80]" wrote:
?
I haven't worked on a 50 in 5 yrs, but I believe the US model draws? around .3A on the 15's, and slightly less on the 8.5/6.5 lines. for test purpose you could get by with that. ?In the UK, ?should approach half that, in theory. (for what that's worth):) Tim
On Friday, July 18, 2014 12:36 AM, "Bob Stewart bob@... [yamahacs80]"
wrote:
?
Yeah, disconnecting stuff was going to be my next thing. I do have another CS50 , but the PSU has been modded and the connections are different. Otherwise that would've been the quickest solution. Will check out what I need for dummy loads as well. Not sure what the current consumption is on the different lines.?
Keep me posted about the 150
Cheers
Bob
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
dummy load may become pivotal in determining the source of the issue.
Alternatively, of course, you could substitute another source of power if available, and i don't mean another cs50 supply, I mean ANY other capable source.?
Given the whine's prevalence on the power lines, you might also want to disconnect the juice to the voice cards all at once and see if
it's still being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had time to check it yet.
good luck
Tim
?
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
Haha yes I'd already clocked that. ;-)
Thanks for the help anyway. Let me know about the 150 once you've had a chance to check it.
Cheers
Bob
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
made a blunder, supply currents won't be different at DC, only AC area.
?Time to get sleep, apparently. T
?
I haven't worked on a 50 in 5 yrs, but I believe the US model draws?
around .3A on the 15's, and slightly less on the 8.5/6.5 lines.
for test purpose you could get by with that.
?In the UK, ?should approach half that, in theory. (for what that's worth):)
Tim
?
Yeah, disconnecting stuff was going to be my next thing. I do have another CS50 , but the PSU has been modded and the connections are different. Otherwise that would've been the quickest solution.
Will check out what I need for dummy loads as well. Not sure what the current consumption is on the different lines.?
Keep me posted about the 150
Cheers
Bob On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
dummy load may become pivotal in determining the source of the issue.
Alternatively, of course, you could substitute another source of power if available, and i don't mean another cs50 supply, I mean ANY other capable source.?
Given the whine's prevalence on the power lines, you might also want to disconnect the juice to the voice cards all at once and see if
it's still being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had time to check it yet.
good luck
Tim
?
I don't have a dummy load unfortunatley,?but did short the sense lines?and look at it. Seemed to be OK, but might need to run it for a while to let it warm up first.
Might just be that something's beginning to fail under load. Just really annoying that it's showing up on all the power lines. Might have a chance to look at it further today, but have a MonoPoly to tune, and a Prophet 5 to diagnose over at a clients.
On Friday, July 18, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
Can you remove the supply, give it all needed dummy loads, and or short sense lines to their respective power lines? Then you can determine if it is strictly from the supply, or a function of the load inducing a resonant freq, or other anomaly. I assume you have a scope.
Tim
?
Only two fuses on the CS50. Voltages are all there, but there's this signal sitting on top of them. Synth works fine other than the whine, and a duff LFO chip.
Thinking it's got to be a duff semiconductor/ IC on the PSU :-(
B On Friday, July 18, 2014, laurie laurie@... [yamahacs80] < yamahacs80@...> wrote:
?
are all 3 fuses intact?
?
?
Hi
Just servicing a CS50, and it's constantly outputting a whine of about 4120Hz.
Unit came to me a bit battered as the PSU had shaken loose and trashed a few things inside.
PSU PCB had become cracked, so replaced that with a working one purchased from Synthparts.
Recapped the new PCB before I fitted it.
I've done the usual, changed the logic on the KAS board and the S/H board, replaced power decoupling caps throughout etc.
The only difference is that originally it took a minute or so to manifest... now it manifests immediately.
I can see the signal on all power lines.
Any thoughts?
B
?
|
Hi Tim
Any news on the 150?
Cheers
Bob
On 18/07/2014 08:25, Tim Conniff
tconno@... [yamahacs80] wrote:
toggle quoted message
Show quoted text
?
dummy load may become pivotal in determining
the source of the issue.
Alternatively, of course, you could
substitute another source of power if available, and i
don't mean another cs50 supply, I mean ANY other
capable source.?
Given the whine's prevalence on the power
lines, you might also want to disconnect the juice to
the voice cards all at once and see if it's still
being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had
time to check it yet.
good luck
Tim
On
Thursday, July 17, 2014 11:38 PM, "Bob Stewart
bob@... [yamahacs80]"
wrote:
?
I don't have a dummy load
unfortunatley,?but did short the sense
lines?and look at it.
Seemed to be OK, but might need to
run it for a while to let it warm up
first.
Might just be that something's
beginning to fail under load. Just
really annoying that it's showing up
on all the power lines. Might have a
chance to look at it further today,
but have a MonoPoly to tune, and a
Prophet 5 to diagnose over at a
clients.
On Friday, July 18, 2014, Tim
Conniff tconno@...
[yamahacs80] < yamahacs80@...>
wrote:
?
Can you
remove the supply,
give it all needed
dummy loads, and or
short sense lines to
their respective
power lines? Then
you can determine if
it is strictly from
the supply, or a
function of the load
inducing a resonant
freq, or other
anomaly. I assume
you have a scope.
Tim
?
Only two
fuses on the
CS50.
Voltages
are all there,
but there's
this signal
sitting on top
of them.
Synth
works fine
other than the
whine, and a
duff LFO chip.
Thinking
it's got to be
a duff
semiconductor/
IC on the PSU
:-(
B
On Friday,
July 18, 2014,
laurie laurie@...
[yamahacs80]
< yamahacs80@...>
wrote:
?
are all 3
fuses intact?
?
?
Hi
Just servicing
a CS50, and
it's
constantly
outputting a
whine of about
4120Hz.
Unit came to
me a bit
battered as
the PSU had
shaken loose
and trashed a
few things
inside.
PSU PCB had
become
cracked, so
replaced that
with a working
one purchased
from
Synthparts.
Recapped the
new PCB before
I fitted it.
I've done the
usual, changed
the logic on
the KAS board
and the S/H
board,
replaced power
decoupling
caps
throughout
etc.
The only
difference is
that
originally it
took a minute
or so to
manifest...
now it
manifests
immediately.
I can see the
signal on all
power lines.
Any thoughts?
B
?
|
found one. Will need $50, but have to test it for you first. Will do that today. Regards Tim
On Saturday, July 19, 2014 4:19 AM, "Robert Stewart bob@... [yamahacs80]" wrote:
?
Hi Tim
Any news on the 150?
Cheers
Bob
On 18/07/2014 08:25, Tim Conniff
tconno@... [yamahacs80] wrote:
?
dummy load may become pivotal in determining
the source of the issue.
Alternatively, of course, you could
substitute another source of power if available, and i
don't mean another cs50 supply, I mean ANY other
capable source.?
Given the whine's prevalence on the power
lines, you might also want to disconnect the juice to
the voice cards all at once and see if it's still
being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had
time to check it yet.
good luck
Tim
On
Thursday, July 17, 2014 11:38 PM, "Bob Stewart
bob@... [yamahacs80]"
wrote:
?
I don't have a dummy load
unfortunatley,?but did short the sense
lines?and look at it.
Seemed to be OK, but might need to
run it for a while to let it warm up
first.
Might just be that something's
beginning to fail under load. Just
really annoying that it's showing up
on all the power lines. Might have a
chance to look at it further today,
but have a MonoPoly to tune, and a
Prophet 5 to diagnose over at a
clients.
On Friday, July 18, 2014, Tim
Conniff tconno@...
[yamahacs80] < yamahacs80@...>
wrote:
?
Can you
remove the supply,
give it all needed
dummy loads, and or
short sense lines to
their respective
power lines? Then
you can determine if
it is strictly from
the supply, or a
function of the load
inducing a resonant
freq, or other
anomaly. I assume
you have a scope.
Tim
?
Only two
fuses on the
CS50.
Voltages
are all there,
but there's
this signal
sitting on top
of them.
Synth
works fine
other than the
whine, and a
duff LFO chip.
Thinking
it's got to be
a duff
semiconductor/
IC on the PSU
:-(
B
On Friday,
July 18, 2014,
laurie laurie@...
[yamahacs80]
< yamahacs80@...>
wrote:
?
are all 3
fuses intact?
?
?
Hi
Just servicing
a CS50, and
it's
constantly
outputting a
whine of about
4120Hz.
Unit came to
me a bit
battered as
the PSU had
shaken loose
and trashed a
few things
inside.
PSU PCB had
become
cracked, so
replaced that
with a working
one purchased
from
Synthparts.
Recapped the
new PCB before
I fitted it.
I've done the
usual, changed
the logic on
the KAS board
and the S/H
board,
replaced power
decoupling
caps
throughout
etc.
The only
difference is
that
originally it
took a minute
or so to
manifest...
now it
manifests
immediately.
I can see the
signal on all
power lines.
Any thoughts?
B
?
|
Hi Tim
Cool. PM me once you've tested it (if it works), with your paypal details and I'll transfer funds.
Cheers
Bob
On Saturday, July 19, 2014, Tim Conniff tconno@... [yamahacs80] < yamahacs80@...> wrote:
?
found one. Will need $50, but have to test it for you first. Will do that today.
Regards
Tim
?
Hi Tim
Any news on the 150?
Cheers
Bob
On 18/07/2014 08:25, Tim Conniff
tconno@... [yamahacs80] wrote:
?
dummy load may become pivotal in determining
the source of the issue.
Alternatively, of course, you could
substitute another source of power if available, and i
don't mean another cs50 supply, I mean ANY other
capable source.?
Given the whine's prevalence on the power
lines, you might also want to disconnect the juice to
the voice cards all at once and see if it's still
being heard, just to further rule out stuff.
Btw, I have found a 150, just haven't had
time to check it yet.
good luck
Tim
On
Thursday, July 17, 2014 11:38 PM, "Bob Stewart
bob@... [yamahacs80]"
wrote:
?
I don't have a dummy load
unfortunatley,?but did short the sense
lines?and look at it.
Seemed to be OK, but might need to
run it for a while to let it warm up
first.
Might just be that something's
beginning to fail under load. Just
really annoying that it's showing up
on all the power lines. Might have a
chance to look at it further today,
but have a MonoPoly to tune, and a
Prophet 5 to diagnose over at a
clients.
On Friday, July 18, 2014, Tim
Conniff tconno@...
[yamahacs80] < yamahacs80@...>
wrote:
?
Can you
remove the supply,
give it all needed
dummy loads, and or
short sense lines to
their respective
power lines? Then
you can determine if
it is strictly from
the supply, or a
function of the load
inducing a resonant
freq, or other
anomaly. I assume
you have a scope.
Tim
?
Only two
fuses on the
CS50.
Voltages
are all there,
but there's
this signal
sitting on top
of them.
Synth
works fine
other than the
whine, and a
duff LFO chip.
Thinking
it's got to be
a duff
semiconductor/
IC on the PSU
:-(
B
On Friday,
July 18, 2014,
laurie laurie@...
[yamahacs80]
< yamahacs80@...>
wrote:
?
are all 3
fuses intact?
?
?
Hi
Just servicing
a CS50, and
it's
constantly
outputting a
whine of about
4120Hz.
Unit came to
me a bit
battered as
the PSU had
shaken loose
and trashed a
few things
inside.
PSU PCB had
become
cracked, so
replaced that
with a working
one purchased
from
Synthparts.
Recapped the
new PCB before
I fitted it.
I've done the
usual, changed
the logic on
the KAS board
and the S/H
board,
replaced power
decoupling
caps
throughout
etc.
The only
difference is
that
originally it
took a minute
or so to
manifest...
now it
manifests
immediately.
I can see the
signal on all
power lines.
Any thoughts?
B
?
|
