Vintage Synth Repair

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, "Brian" <brian@...> wrote:
>
> You can replace with non-polar without any problem
> 
>  
> 
> Regards
> 
> Brian G3OYU
> 
>  
> 
> From: vintagesynthrepair@yahoogroups.com
> [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Gil
> Sent: 10 December 2012 1:13
> To: vintagesynthrepair@yahoogroups.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 !
>