Power Supply Help

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ejukated
Posts: 443
Joined: Wed Mar 04, 2009 8:52 pm

Power Supply Help

Post by ejukated »

Hey all,

I'm looking at a Redarc battery charger system which has 240V input, DC-DC charging and solar inputs. These systems are typically used on caravans etc to manage the 12V onboard systems. In the unit im looking at, the 240V section has failed, looking at the board, there appears to be 2 blown SMD resistors in the initial RC filter stage and later on after the bridge rectifier.

Given the readable part of the resistor says R1.., I'd assume it is a 0.1ohm 1W resistor, Im thinking to replace this with say a 5W wirewound resistor as I cant see how a 1W resistor can handle the potential full 10A @ 240V (unit is rated at 280W)

Any thoughts from the more knowledgeable on here?

Attached is the 240V side of the board I've sketched out along with a pic of the blown part. (R253 & R223)

Cheers
Attachments
Input Stage Diagram.pdf
(306.83 KiB) Downloaded 220 times
P4250662.JPG
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