OK, when I am looking at the IC how do i know which pin is pin 1? I
found one pin on IC12 that measures +/- 4.7 v but no pin that changes
on IC13. Hmm
--- In
PolySix@yahoogroups.com, Johannes Hausensteiner <jo.synth@c...>
wrote:
> On KLM-367 check the following:
> ∗ IC12 (TL072) pin1: must be -5V .. +5V according to PW/PWM poti
> if not, replace IC12
> ∗ IC13 (4558) pin1: must be -5V .. +5V according to PWM SPEED poti
> if not, replace IC13
> ∗ Set PWM SPEED to slowest and check IC1 (4066)/pin9: must change from
> minus to plus voltage and back (I dont know the exact values; will
> be at least -3V..+3V)
> if not, replace IC20 (LM13600) and/or IC15 (4558)
> ∗ IC1/pin6: must be +5V when WAVEFORM is at PWM position, otherwise 0V.
> if not, replace IC3 (LM339)
> ∗ IC1/pin8: must be the same as IC1/pin9 when WAVEFORM is at PWM
> position, if not replace IC1 (4066).
> ∗ TP1 (PW/PWM) near IC12: according to service manual "PW/PWM check
> and adjustment"
> if not OK, replace IC20 (LM13600) and/or IC15 (4558)
>
> I hope this helps,
>
> Johannes
>
>
> ciscomanvann wrote:
> > Nothing happens. It plays, but the width or pwm does not change. I
> > have a multimeter, how do i check this stuff out? I dont know a whole
> > lot about ICs.
> >
> > --- In PolySix@yahoogroups.com, The Old Crow <oldcrow@o...> wrote:
> >
> >> First thing to do is set VCO to PW and move the width knob from 0
> >
> > to 10
> >
> >>and back to 0 and listen to see if it changes accordingly. Then
> >
> > set it to
> >
> >>10 and change the VCO mode to PWM and move the PWM speed knob from
> >
> > 0 to 10
> >
> >>slowly and note if the cyclic modulation is audible.
> >>
> >> If nothing is working then I would imagine either IC20 (LM13600)
> >
> > needs
> >
> >>replaced, or the analog switch section IC1C died and IC1 needs
> >
> > replaced,
> >
> >>or perhaps the control voltages off deMUX IC19 aren't getting there
> >
> > and
> >
> >>IC19, IC12 or IC13 is to blame (least likely though).
> >>
> >> Use my schematic as it is much easier to read than the old
> >
> > service
> >
> >>manual copy. PWM circuit is on the far right, about 2/3 of the way
> >
> > down.
> >
> >>It is marked "PWM MG":
> >>
> >>
> >
> > http://www.oldcrows.net/~oldcrow/synth/korg/polysix/crowlm367/klm367a_
> > eagle_schem.gif
> >
> >>
> >> Hope this helps,
> >>
> >>Crow
> >>/∗∗/
> >>
> >>On Wed, 31 Dec 2003, ciscomanvann wrote:
> >>
> >>
> >>>I know this sounds stupid, but how can i tell if the PWM is
> >
> > working?
> >
> >>>If it is not, where do I start looking to fix it?
> >>>Thanks!
> >
> >
> >
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