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Article #1644Re: Understanding a split-mode power supply.
From: Phil Allison
Date: Sun, 04 Jan 2009 06:44
Date: Sun, 04 Jan 2009 06:44
38 lines
2381 bytes
2381 bytes
"Sylvia Else" > Phil Allison wrote: >> ** In an earlier post you state the PCB had been subjected to water >> ingress and insect attack - so almost anything is possible. >> >> Odds are, the switching transistor was forced hard on by the above, >> taking out the 8.2 ohms and Q1 in quick succession. >> >> Relace whatever parts you find are damaged, clean the PCB carefully with >> detergent and a brush (as you would washing glass ware etc in the sink ) >> rinse with clean water and dry thoroughly with lotsa hot air ( ie a hair >> dryer). >> >> Then cross you fingers and try it again. >> >> If all is well, coat the PCB is clear acrylic lacquer to help it survive. >> > > It's true that I mentioned brushing away a dead spider. > > I wish I'd noted exactly where the spider was. It conceivably was around > the 200K resistor, which could explain both the failures, and the demise > of the spider. > > Anyone know the resistance of a small spider before it dies from shock? ** If you see one with three red stripes across its abdomen - means it is 2.2 kohms, +/- 20 % ............. ..... Phil
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