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2015-08-10 by moogchild synthdrome
Hi again. This time I have a Polysix whose VCOs are always modulated by a very slow sine or triangle wave. Of course all modulation controls in the panel and mod wheel are at zero value. If I change the battery board using a good one, the modulation disappears, so it is clearly a problem of the KLM-367A. Do you know what parts should I check?. Thank you for your help. Kind regards Manuel
2015-08-10 by <backshall1@bellsouth.net>
Does it change with the MG speed control or does it seem unrelated to the MG? Don B.
From: mailto:PolySix@yahoogroups.com Sent: Monday, August 10, 2015 2:15 PM To: PolySix@yahoogroups.com Subject: [PolySix] VCOs slightly modulated due to battery board malfunction Hi again. This time I have a Polysix whose VCOs are always modulated by a very slow sine or triangle wave. Of course all modulation controls in the panel and mod wheel are at zero value. If I change the battery board using a good one, the modulation disappears, so it is clearly a problem of the KLM-367A. Do you know what parts should I check?. Thank you for your help. Kind regards Manuel
2015-08-10 by moogchild synthdrome
No, it isn't related with the speed of the MG. Once I repaired another KLM-367A board which produced a high speed modulation in the sound, I replaced IC30 and the problem was solved. But this time I've replaced IC30 and IC31 and the slow modulation remains. All other functions are ok.
--------------------------------------------
El lun, 10/8/15, backshall1@bellsouth.net [PolySix] <PolySix@yahoogroups.com> escribió:
Asunto: Re: [PolySix] VCOs slightly modulated due to battery board malfunction
Para: PolySix@yahoogroups.com
Fecha: lunes, 10 de agosto, 2015 20:32
Does it change with the MG speed control or does it
seem unrelated to the
MG?
Don B. From: mailto:PolySix@yahoogroups.com
Sent: Monday, August 10, 2015 2:15 PM
To: PolySix@yahoogroups.com
Subject: [PolySix] VCOs slightly modulated due
to battery board
malfunction
Hi again. This time I have a Polysix whose VCOs are
always modulated by a
very slow sine or triangle wave. Of course all modulation
controls in the panel
and mod wheel are at zero value. If I change the battery
board using a good one,
the modulation disappears, so it is clearly a problem of the
KLM-367A. Do you
know what parts should I check?. Thank you for your help.
Kind
regards
Manuel
#yiv4210018239 #yiv4210018239 --2015-08-10 by <backshall1@bellsouth.net>
How about PWM Speed or Effects Speed? They also have their own LFO signal that could be bleeding in somewhere. Don B.
From: mailto:PolySix@yahoogroups.com Sent: Monday, August 10, 2015 2:40 PM To: PolySix@yahoogroups.com Subject: Re: [PolySix] VCOs slightly modulated due to battery board malfunction No, it isn't related with the speed of the MG. Once I repaired another KLM-367A board which produced a high speed modulation in the sound, I replaced IC30 and the problem was solved. But this time I've replaced IC30 and IC31 and the slow modulation remains. All other functions are ok. -------------------------------------------- El lun, 10/8/15, backshall1@bellsouth.net [PolySix] <PolySix@yahoogroups.com> escribió: Asunto: Re: [PolySix] VCOs slightly modulated due to battery board malfunction Para: PolySix@yahoogroups.com Fecha: lunes, 10 de agosto, 2015 20:32 Does it change with the MG speed control or does it seem unrelated to the MG? Don B. From: mailto:PolySix@yahoogroups.com Sent: Monday, August 10, 2015 2:15 PM To: PolySix@yahoogroups.com Subject: [PolySix] VCOs slightly modulated due to battery board malfunction Hi again. This time I have a Polysix whose VCOs are always modulated by a very slow sine or triangle wave. Of course all modulation controls in the panel and mod wheel are at zero value. If I change the battery board using a good one, the modulation disappears, so it is clearly a problem of the KLM-367A. Do you know what parts should I check?. Thank you for your help. Kind regards Manuel #yiv4210018239 #yiv4210018239 --
2015-08-10 by moogchild synthdrome
Definetely not, I've double checked it. Effects off, sawtooth wave. Same slow VCOs modulation (about 5 secs per cycle) independently of the speed of the three LFOs in the Polysix. If I replace the KLM-367A the modulation disappears.
--------------------------------------------
El lun, 10/8/15, backshall1@bellsouth.net [PolySix] <PolySix@yahoogroups.com> escribió:
Asunto: Re: [PolySix] VCOs slightly modulated due to battery board malfunction
Para: PolySix@yahoogroups.com
Fecha: lunes, 10 de agosto, 2015 20:57
How about PWM Speed or Effects Speed? They also have
their own LFO signal
that could be bleeding in somewhere.
Don B. From: mailto:PolySix@yahoogroups.com
Sent: Monday, August 10, 2015 2:40 PM
To: PolySix@yahoogroups.com
Subject: Re: [PolySix] VCOs slightly modulated
due to battery board
malfunction
No, it isn't related with the speed of the MG. Once I
repaired another
KLM-367A board which produced a high speed modulation in the
sound, I replaced
IC30 and the problem was solved. But this time I've
replaced IC30 and IC31 and
the slow modulation remains. All other functions are
ok.
--------------------------------------------
El lun, 10/8/15,
backshall1@bellsouth.net [PolySix]
<PolySix@yahoogroups.com>
escribió:
Asunto: Re:
[PolySix] VCOs slightly modulated due to battery
board malfunction
Para:
PolySix@yahoogroups.com
Fecha: lunes, 10 de
agosto, 2015
20:32
Does
it change with the MG speed control or does it
seem unrelated to the
MG?
Don B.
From:
mailto:PolySix@yahoogroups.com
Sent: Monday, August 10, 2015 2:15
PM
To: PolySix@yahoogroups.com
Subject: [PolySix] VCOs
slightly
modulated due
to battery board
malfunction
Hi again. This time I have a
Polysix whose VCOs are
always modulated by a
very slow sine or triangle
wave. Of course all modulation
controls in
the panel
and mod wheel are at
zero value. If I change the battery
board
using a good one,
the
modulation disappears, so it is clearly a problem of the
KLM-367A. Do you
know what parts should I check?. Thank you
for your help.
Kind
regards
Manuel
#yiv4210018239
#yiv4210018239 --
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border:1px solid
#d8d8d8;font-family:Arial;margin:10px
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#yiv42100182392015-08-10 by klosmon
Next step is to begin eliminating possible causes. Lift the end of R11 to see if the effect goes away. Then lift R9. R11 carries the internal mod signal; R9 carries the signal from the mod wheel. If the effect continues with both of these disconnected, it's coming from somewhere else. You then have to backtrack through the opamp buffers & demultiplexers for the VCO control voltage. It is sometimes possible on battery-damaged boards for a signal to bleed through to other traces. ~G On 8/10/2015 1:33 PM, moogchild synthdrome moogchild@yahoo.es [PolySix] wrote:
> > Definetely not, I've double checked it. Effects off, sawtooth wave. > Same slow VCOs modulation (about 5 secs per cycle) independently of > the speed of the three LFOs in the Polysix. If I replace the KLM-367A > the modulation disappears. > > -------------------------------------------- > El lun, 10/8/15, backshall1@bellsouth.net [PolySix] > <PolySix@yahoogroups.com> escribi�: > > Asunto: Re: [PolySix] VCOs slightly modulated due to battery board > malfunction > Para: PolySix@yahoogroups.com > Fecha: lunes, 10 de agosto, 2015 20:57 > > > > > > > > > > > > > > > > > How about PWM Speed or Effects Speed? They also have > their own LFO signal > that could be bleeding in somewhere. > Don B. > > > >