Vintage Synth Repair

Some non-polar caps do have a positive and negative marking, don't ask me
why I don't know.  You would need to consult the schematic to ascertain
whether or not the caps get reverse polarity volts on them at any time.

Regards

Brian G3OYU

 

From: vintagesynthrepair@yahoogroups.com
[mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Gil
Sent: 11 December 2012 9:07
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Re: Don't know if the original caps were polar
or bi-polar (E-II)

 

  


Thanks,

I replaced them with bi-polars, no change in behavior (works just as before,
no sample in signal).

What do you think ? should I keep the bi-polars there, or switch back to the
polars ?

As I said before, the schematics calls for bi-polars, but the on the circuit
board there are + signs near each cap, implying for polar capacitors... Why
would they mark the polarity on the board if they ask for non-polar caps
there ?

Just wondering...

--- In vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> , "Brian" <brian@...> wrote:
>
> You can replace with non-polar without any problem
> 
> 
> 
> Regards
> 
> Brian G3OYU
> 
> 
> 
> From: vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> 
> [mailto:vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> ] On Behalf Of Gil
> Sent: 10 December 2012 1:13
> To: vintagesynthrepair@yahoogroups.com
<mailto:vintagesynthrepair%40yahoogroups.com> 
> Subject: [vintagesynthrepair] Don't know if the original caps were polar
or
> bi-polar (E-II)
> 
> 
> 
> 
> 
> I have a nice Emulator II which doesn't sample from the day I got it.
> 
> You see no signal when playing into the input (using another synth, or an
> electric guitar). 
> 
> I decided to investigate this 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 when recapping the machine.
> 
> 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 ?
> 
> You can see the diagram at page 42 of the manual, here:
> 
>
http://www.synthesizerarchiv.de/circuits/emu/emulator2_circuits/emulator2_ci
> rcuits.pdf
> 
> Thanks !
>