|
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
|
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?
|
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?
|
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
?
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?
|
I recently read about a modification that was done by Kent Spong which involved re-routing the cable loom because it would produce some kind of high-pitched whine. Maybe Kent could elaborate on his?
?
Mine does that as well but it's only audible when playing lower notes.
?
Stephen
?
Gesendet:?Donnerstag, 11. Juni 2015 um 17:06 Uhr
Von:?"bob@... [yamahacs80]"
An:?yamahacs80@...
Betreff:?[yamahacs80] HIgh Pitched Whine
?
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
|
This is pretty loud. And as I said, it seems to be eminating from the PSU... As in you can hear the power transistor on the -15Vrail whining away, if you've got the audio out disconnected. But it manifests on the audio out as well. Round about 5KHz I reckon.
On Thursday, June 11, 2015, 'Stephen Parsick' wavecomputer360@... [yamahacs80] < yamahacs80@...> wrote:
?
I recently read about a modification that was done by Kent Spong which involved re-routing the cable loom because it would produce some kind of high-pitched whine. Maybe Kent could elaborate on his?
?
Mine does that as well but it's only audible when playing lower notes.
?
Stephen
?
?
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
|
Did you succeed fixing this 5kHz whining?
|
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
Gesendet:?Samstag, 09. Januar 2016 um 18:18 Uhr
Von:?"fanwander@... [yamahacs80]"
An:?yamahacs80@...
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Did you succeed fixing this 5kHz whining?
|
Not had the time to investigatefor a while, but am aiming to get stuck in again next month. Reckon the fitst thing to do is look at decoupling caps. Bane of my life this CS ;-)
B?
On Saturday, 9 January 2016, 'Stephen Parsick' wavecomputer360@... [yamahacs80] < yamahacs80@...> wrote:
?
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
?
Did you succeed fixing this 5kHz whining?
|
Don't take my word for it, I can only vaguely remember what was written in the interview. I seem to remember that it had something to do with the illuminated push buttons as well.
?
Maybe some other German-speaking member of this group has the issue at hand?
?
Stephen
?
Gesendet:?Sonntag, 10. Januar 2016 um 07:55 Uhr
Von:?"Bob Stewart bob@... [yamahacs80]"
An:?"yamahacs80@..."
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Not had the time to investigatefor a while, but am aiming to get stuck in again next month.
Reckon the fitst thing to do is look at decoupling caps.
Bane of my life this CS ;-)
?
?
?
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
?
Did you succeed fixing this 5kHz whining?
?
?
?
?
|
Decoupling caps are never a bad place to start looking though. They must be 40 years old.
Illuminated push buttons? There aren't any illuminated push buttons on a CS50?
On Sunday, 10 January 2016, 'Stephen Parsick' wavecomputer360@... [yamahacs80] < yamahacs80@...> wrote:
?
Don't take my word for it, I can only vaguely remember what was written in the interview. I seem to remember that it had something to do with the illuminated push buttons as well.
?
Maybe some other German-speaking member of this group has the issue at hand?
?
Stephen
?
?
Not had the time to investigatefor a while, but am aiming to get stuck in again next month.
Reckon the fitst thing to do is look at decoupling caps.
Bane of my life this CS ;-)
?
B?
On Saturday, 9 January 2016, 'Stephen Parsick' [yamahacs80] <> wrote:
?
?
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
Gesendet:?Samstag, 09. Januar 2016 um 18:18 Uhr
Von:?"fanwander@... [yamahacs80]" <yamahacs80@...>
An:?yamahacs80@...
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Did you succeed fixing this 5kHz whining?
?
?
?
?
|
I have that very?problem with my CS80, and the interview I was referring to dealt with a CS80, hence my remark.
?
Stephen
?
Gesendet:?Sonntag, 10. Januar 2016 um 13:11 Uhr
Von:?"Bob Stewart bob@... [yamahacs80]"
An:?"yamahacs80@..."
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Decoupling caps are never a bad place to start looking though. They must be 40 years old.
?
Illuminated push buttons? There aren't any illuminated push buttons on a CS50?
?
?
?
Don't take my word for it, I can only vaguely remember what was written in the interview. I seem to remember that it had something to do with the illuminated push buttons as well.
?
Maybe some other German-speaking member of this group has the issue at hand?
?
Stephen
?
?
Not had the time to investigatefor a while, but am aiming to get stuck in again next month.
Reckon the fitst thing to do is look at decoupling caps.
Bane of my life this CS ;-)
?
B?
On Saturday, 9 January 2016, 'Stephen Parsick' [yamahacs80] <> wrote:
?
?
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
Gesendet:?Samstag, 09. Januar 2016 um 18:18 Uhr
Von:?"fanwander@... [yamahacs80]" <yamahacs80@...>
An:?yamahacs80@...
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Did you succeed fixing this 5kHz whining?
?
?
?
?
?
?
?
?
|
Ah... OK cool.
toggle quoted message
Show quoted text
On Sunday, 10 January 2016, 'Stephen Parsick' wavecomputer360@... [yamahacs80] < yamahacs80@...> wrote:
?
I have that very?problem with my CS80, and the interview I was referring to dealt with a CS80, hence my remark.
?
Stephen
?
?
Decoupling caps are never a bad place to start looking though. They must be 40 years old.
?
Illuminated push buttons? There aren't any illuminated push buttons on a CS50?
?
On Sunday, 10 January 2016, 'Stephen Parsick' [yamahacs80] <> wrote:
?
?
Don't take my word for it, I can only vaguely remember what was written in the interview. I seem to remember that it had something to do with the illuminated push buttons as well.
?
Maybe some other German-speaking member of this group has the issue at hand?
?
Stephen
?
Gesendet:?Sonntag, 10. Januar 2016 um 07:55 Uhr
Von:?"Bob Stewart bob@... [yamahacs80]" <yamahacs80@...>
An:?"yamahacs80@..." <yamahacs80@...>
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Not had the time to investigatefor a while, but am aiming to get stuck in again next month.
Reckon the fitst thing to do is look at decoupling caps.
Bane of my life this CS ;-)
?
B?
On Saturday, 9 January 2016, 'Stephen Parsick' [yamahacs80] <> wrote:
?
?
A while ago there was a report on a German synth collector/musician in KEYBOARDS magazine in which he described this problem. He had some decoupling capacitors replaced which fixed the problem -- maybe someone could look up more accurate details?
?
Stephen?
?
Gesendet:?Samstag, 09. Januar 2016 um 18:18 Uhr
Von:?"fanwander@... [yamahacs80]" <yamahacs80@...>
An:?yamahacs80@...
Betreff:?Re: [yamahacs80] HIgh Pitched Whine
?
Did you succeed fixing this 5kHz whining?
?
?
?
?
?
?
?
?
|
