Thanks !
From close up picture I see of the E-II, they all have aluminium caps in that place. Couldn't figure out from the images if they were polar or not.
I wonder if the sample in circuit on my E-II doesn't work because I used polar caps there for a while. Could that damage the circuit ?
--- In emulatorII-list@yahoogroups.com, "kgslug2" <kevingibson952@...> wrote:
>
> Gil,
>
> On mine, both "C66" and C67" were actually two caps: two 10uF 25v tants, with their negative leads soldered together and their positive leads soldered to the PCB pads - I believe this gives a total capacitance of 5uF, but I am not sure how it affects polarity!
>
> I should have taken a close up picture, but I am recapping the board and I have already replaced these. Mine also has the + symbols on the board, but I used 4.7uF bipolar electrolytics as per the schematic. Using polar caps where bipolar ones are required would be a problem, but I can't see any issue using bipolar where polar is specified.
>
> I still haven't been able to test it - lots of dead RAM chips....
>
> Kevin
>
> --- In emulatorII-list@yahoogroups.com, "Gil" <gilwe@> wrote:
> >
> > Here's a picture of the location I refer to:
> >
> > http://www.fileden.com/files/2009/5/8/2434738/IMG_3507.JPG
> >
> >
> >
> >
> >
> >
> > --- In emulatorII-list@yahoogroups.com, "Gil" <gilwe@> wrote:
> > >
> > > Will you please describe exactly what you see on your E-II as C66 and C67 on the audio board ??
> > >
> > > What do you mean by two tantalums in series ?
> > >
> > > Which values are they ? and how are they wired ?
> > >
> > > If you could make a close up picture of the area I will be thankful !
> > >
> > >
> > >
> > >
> > >
> > > --- In emulatorII-list@yahoogroups.com, "kgslug2" <kevingibson952@> wrote:
> > > >
> > > > On mine, they are not even aluminium electrolytics. each is a pair of tantalums wired in series. I can't tell you if sampling works as at the moment my EII won't even boot.
> > > >
> > > > Kevin
> > > >
> > > > --- In emulatorII-list@yahoogroups.com, "Gil" <gilwe@> wrote:
> > > > >
> > > > > I haven't managed to get my Emulator II to sample from the day I got it.
> > > > >
> > > > > I see no signal when playing into the input (using another synth, or an electric guitar).
> > > > >
> > > > > I decided to investigate this further and found that what seems to be the sampling circuit, has two electrolyte caps, which on the schematics are marked as "alum-electro (nonpolar) 4.7uf" but on the actual board, regular POLAR caps are used. These caps I put myself while recapping the machine when I got it a few years ago.
> > > > >
> > > > > I tend to think that this causes the sampling circuit not to work,
> > > > > BUT - a closer look at the board reveals a + sign near each of these two caps, as if the engineers did intend to use regular POLAR caps there...
> > > > >
> > > > > I'm afraid to replace them with non-polars so I don't damage the circuit...
> > > > >
> > > > >
> > > > > Any advice / info on this ? Will anyone be able to take a look at his E-II voice board and check if these two electrolyte 4.7uf caps are bipolar (there should be a "NP" mark on them, and no polarity marking) ?
> > > > >
> > > > > They are right under the power supply at the top-right corner of the left board.
> > > > >
> > > > > The diagram is probably page 42 in the manual:
> > > > >
> > > > > http://www.synthesizerarchiv.de/circuits/emu/emulator2_circuits/emulator2_circuits.pdf
> > > > >
> > > > > Thanks !
> > > > >
> > > >
> > >
> >
>