A500 Backwards Capacitors

[chue]

I recapped my Amiga 500 Rev 6A board and was testing my work with a multi-meter.

My testing method was to connect one test lead to ground, and the other test lead to the terminals of the capacitors. When doing this I expected that the negative terminal should show continuity with ground (and of course the positive terminal should not).

I found two capacitors where the positive terminal shows continuity to ground, but the negative lead does not. So clearly the silk-screening is wrong on those caps.

In any case, these are the backwards caps: C304 (audio filter), C822 (to the right of the even CIA). The attached picture shows the offending caps.

I also did the same testing on an A500 Rev 5 board, and it is the same there.

My plan is to fix the two caps, but is there any reason not to?

[chue]

I rechecked the board and it looks like 822 is silk-screened correctly. I just read the silks-screening wrong. So it looks like the only backwards cap is 304.

[Daedalus]

C304 is supposed to be that way around. It is on the negative 12V rail, so its negative terminal is at -12V, and the positive terminal is at 0V. This is the correct orientation of that capacitor, so nothing to worry about.

[jimbob]

Audio circuit has a +ve and -ve power supply. C304 is probably correct as you have it, plus terminal to ground and minus terminal to -ve supply.

Don't take my word for it though, check the schematic.

Edit: ninja'd

[chue]

Forgot about the negative rails! Thank you, gentlemen!