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Old Jan 30, 2011, 04:14 PM
Aralan is offline
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Joined Sep 2010
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I've just finished doing some bench testing. The pinout on ribbon cable looks to be a bit different on this supply. I probed the connectors on hot plug board and the header and found that shorting pins 3,5,6 does the trick. It does not appear that the hot plug board connects any of the pins on the ribbon cable to ground. I connected to DC ground and probed all pins on the hot plug board header and did not find any connections. Pin 1 (the red wire) coming from the main board side is to ground.

As for floating the DC ground, the screw on the left side of the main board, closest to the hot plug board, appears to be responsible for connecting DC ground to the case. After removing this screw, I found no continuity between DC ground and the case, nor DC ground and AC ground. It does seem however that there is a contact on the back side of the main board that connects to the case when the screw is holding it down. Pushing down on the board caused the DC ground to become connected to the case again. In order to eliminate that I'll need to attach something to the underside of the board to isolate that connection from the case, so it looks like I need to revisit removing the main board. Still don't have that figure out. I'm obviously missing something.

Removing the green wire from the case did not eliminate the AC ground. There must be another connection that I can't see. I don't think it is worth tracking down though, as floating the DC ground was quite easy.
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