Vintage Synth Repair

Thanks Brian, after reading up on this last night it seems obvious now, not the symbols but your explanation & how the AC signal is working in the circuit. It's all stuff I learnt way back when I studied electronics (yep I have actually studied properly which is hard to believe I know!), it's all filtering back slowly though! Thanks for answering my silly questions!

Nick



________________________________
 From: Brian <brian@...>
To: vintagesynthrepair@yahoogroups.com 
Sent: Tuesday, 26 February 2013, 8:07
Subject: RE: [vintagesynthrepair] Dumb question, but this is driving me nuts... > Older Cap Polarity
 

  
Hi Nick
As far as I know this symbol is for a non-polarized capacitor and will be non-polarized for a reason!  The reason is that the voltage polarity can swing both positive and negative.  This means that you cannot use a polarized electrolytic device.
If the capacitance value is low enough there is no reason why you should not us any capacitor such as paper, polyester, polycarbonate etc.  This would explain why the existing devices have no polarity markings.
If the value is too high then you will have to use non-polarized electrolytics.  If you use polarized electrolytics there is a danger that they will give up the ghost or even collapse by blowing out the end cap, at the worst they could explode.  This could occur if they sit there with reverse polarity of a high enough voltage for any length of time, the higher the reverse voltage the shorter the time before they pack up, and yes I have had this happen on a number of occasions and believe me you don’t want to have to clean up the mess they make when they explode!
Regards
Brian G3OYU
 
From:vintagesynthrepair@yahoogroups.com [mailto:vintagesynthrepair@yahoogroups.com] On Behalf Of Nick Bell
Sent: 25 February 2013 5:33
To: vintagesynthrepair@yahoogroups.com
Subject: [vintagesynthrepair] Dumb question, but this is driving me nuts... > Older Cap Polarity [1 Attachment]
 
  
[Attachment(s) from Nick Bell included below] 
This is def going to seem a bit of a dumb question but I am just trying to identify the polarity of some old electrolytic caps I am replacing. The old ones don't have any markings, they just have most of the writing on one side. On the board the symbol is marked as per my attachment but without the + & - that I have added.
 
Can someone tell me please if I am correct with my polarity markings or not! Internet image search for old cap symbols just comes up with something similar but the slope of the lines in the middle go the other way (they go up from left to right instead & indicate + on the right). Confused!
 
Thanks 
Nick