"non-polar" capacitor?

Jim Brain brain at jbrain.com
Sun Jul 31 00:24:51 CDT 2016

Since I acquired a Coco Orchestra 90 unit awhile back, and I am trying 
to find the source of some humming in my system when the Orch 90 unit is 
operational, I looked at the schematic:


(page 109 of the PDF)

I understand the ROM, the resistor ladders, and the latches, but analog 
is not my strong suit.  I made my way through the op-amp design, but I 
am stumped on one component (actually three)?

C7,C9, and C10

They look like electrolytic polarized caps, but are NP (non polarized), 
with no '+' on the schematic.

Can someone shed light on what these are and where you would find them 
(or if they can safely be replaced with another kind of capacitor)?  I 
will admit I've never seen mention of these before now.

Are they "bipolar"?


Or, are they called something else now?


Jim Brain
brain at jbrain.com

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