1 (edited by kabatronix 2011-04-30 04:16:30)

Topic: chumby one power supply failure releasing electrolytics into the air

purchased on xmas 09 my chumby one power supply failed yesterday prematurely.

as often switch mode powersupplies are equipped with inappropriate components especially in the output section.
capacitors capable of highfrequency ripple currents in this section are expensive, so cheapo stuff is used instead.

these capacitors overheat and discharge their poisonous electrolytics into the air very slowly and therefore not always noticable until the component fails completely leaving your power supply unbypassed puking its ripple directly into the chumby circuitry.

constant restarts, chirping noise and/or hanging are the results with an internal backup battery attached (else the unit wont even react on the powerbutton).

changing the chinese crap cap to an highquality panasonic type 1000µ 10v 105°C FM type healed my power supply.

oh yes, i had to crack the housing to fix it and mold a notch in the uppercase by hot air gun to be able to glue the case together again securely by means of cyan acrylate.

the new capacitor is a bit higher, so it excesses the headroom available.

don´t do this repair on your own, if your not intimate with electronics and the regarding safety rules.