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D21 Blown and TR9 maybe

Posted by Dunston-UK 
D21 Blown and TR9 maybe
June 10, 2018 09:21PM
@DC42. Can this be fixed or repaired by a bridge in some way it also took the diode in front of the second PWM fan header with it, TR9.

looking more at the board it also looks like TR9 took a hit as well.

I would gladly pay someone £40 / £50 to fix it if they could.
Re: D21 Blown and TR9 maybe
June 11, 2018 04:03AM
D21 is the flyback diode for the FAN2 output. It's very unusual to see a flyback diode fail, assuming it was fitted the right way round in the first place. If you only connect ordinary brushless DC fans to the FAN2 output then D21 isn't needed anyway. The purpose of D21 is to protect the mosfet TR1 from the back emf if you connect an inductive load such as an air pump to the FAN2 output.

TR9 is the mosfet that switches the FAN1 output. I agree, it looks damaged. A short circuit across the FAN1 output would cause this kind of damage.

Which fan outputs are working?

From your signature, I presume you are in the UK. I can replace the TR9 mosfet, also I could replace D21 if the PCB pads for it are intact - although you probably don't need it, see above. Send me a PM if interested.

Edited 1 time(s). Last edit at 06/11/2018 06:31AM by dc42.

Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: D21 Blown and TR9 maybe
June 11, 2018 05:17AM
PM sent smiling smiley
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