Doepfer

hello again,
well, IIRC, this problem's differential diagnosis is:
if the specific PWM problem appears alone, chances are
that the cause is a defective CEM3340 chip.
if this specific PWM problem appears together with
another problem-that being the vco not sounding
correctly in the higher registers, then chances are
that the cause is the hardsync input socket.
best regards,
Bakis.



--- Bakis Sirros <synth_freak_2000@yahoo.com> wrote:

> hello again,
> if i remember right:
> out of the 8 a111's i have,
> one of my a111's had the exact same problem with the
> PWM input and it turned out that its CEM3340 needed
> a
> replacement(wich doepfer replaced and the module
> worked fine afterwards).
> then, after some months, two of my other a111's had
> the exact same PWM problem and, by just plugging a
> cable into the hard sync input and then adjusting
> the
> metal plates of the hardsync input socket, fixed the
> problem entirely!
> so, it seeems that this PWM symptom has two
> different
> causes...
> at least that is my experience so far.
> best regards,    :-)
> Bakis.
> 
> 
> --- Tim Stinchcombe
> <timothy@tstinchcombe.freeserve.co.uk> wrote:
> 
> > Hi Markus,
> > 
> > > I didn't find any hint at the Doepfer page. Any
> > other idea?
> > 
> > After checking some of the history on this
> problem,
> > I realised I too 
> > had this problem when I first got my A-111 (over 4
> > years ago), and 
> > the solution then, by EMIS the UK distributor, was
> > to replace the 
> > CEM3340 chip. In an old email I had written to
> > Dieter at the time, I 
> > mentioned that specifically grounding the hard
> sync
> > input did *not* 
> > cure the problem!
> > 
> > However, checking past messages, the last time
> this
> > appeared seems to 
> > have been post #9193, about a year ago: one of the
> > follow-up posts, 
> > #9203, contained the suggestion from Dieter about
> > grounding the hard-
> > sync input, but checking my module against what he
> > says doesn't make 
> > sense, as the switched contact on mine is *not*
> > grounded (but I'm 
> > guessing on new modules they solder across the
> gap).
> > Hence I suggest 
> > the following:
> > 
> > Insert a patch lead into the hard sync socket, and
> > *deliberately 
> > ground the tip at the other end*.
> > 
> > If this cures it, have a look at the switched
> > contacts on the hard 
> > sync socket - these are the two on the very end of
> > the board. I 
> > suspect that they are bridged with solder: if they
> > are, then probably 
> > a new socket is needed; if they are not, then
> > bridging them with 
> > solder will have the effect of always grounding
> the
> > hard sync line 
> > when no plug is inserted, which hopefully should
> > then give a 
> > permanent solution.
> > 
> > If inserting and grounding the lead doesn't
> totally
> > remove the 
> > problem, then I suspect you'll need a new chip as
> I
> > did!
> > 
> > Tim
> > 
> > 
> > 
> > 
> > 
> > 
> 
> 
> Bakis Sirros - Parallel Worlds
> [Doepfer_a100] group owner
> http://www.parallel-worlds-music.com
> http://www.myspace.com/parallelworldsmusic
> http://www.shimarecords.co.uk
> http://www.rubber.gr
> Athens-Greece
> 
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Bakis Sirros - Parallel Worlds
[Doepfer_a100] group owner
http://www.parallel-worlds-music.com
http://www.myspace.com/parallelworldsmusic
http://www.shimarecords.co.uk
http://www.rubber.gr
Athens-Greece

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