TaylorData
1 Copper

RE: R710 PSU Redundancy Failure

Sorry for the slow reply, out for the holidays and then got sick.

So I left the PSU running and it failed after a few more days. I was able to find documentation on how to fake a power on press for the PSU (aka "The ATX paper clip method") .I had our Electrical Engineer take a look at it since there was little harm to be done.

www.rcgroups.com/.../showpost.php;postcount=3354

I was able to jump start the power supply and found the following:

Ground Supply Kill C6 (to turn on)
Leave PS_ON (A6) open:
· LED green
· 12V standby is OK
· 3.3V Logic is OK
Ground PS_ON signal:
· Fan spins
· But LED becomes amber*
· Main 12V is dead*. Other 12V standby, 3.3V Logic are still fine.

*Checked with a known good supply: LED is green and Main 12V is fine.

Conclusion: suspect the main dc/dc converter (400V to 12V) failed. They could be either switching devices failed (Power Diodes, or MOSFET, or IGBT) or switching control units, or even broken circuit, etc.
If you can find schematic I certainly can trouble shoot further. I do not know if there is an obvious bad component if we are willing to check further inside….

 

I got two more PSUs from the site. One already failed, the other having these 'pre-failure' symptoms that don't report.

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