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shogun
02-06-2008, 11:28 PM
Something for the electronic wizzards

This question came up on Bimmerboard:

Hi

i took out my sword to replace the mosfets on them.
all 4 were fried. I removed all fet's and cleaned up the solder areas.

as a sanity check I measured between the 2 main big traces on the circuit board looking for shorts and measured about 52 K-ohms. looking for info I came across a website that said there should be infinite resistance between the two main solder areas.

trying to follow the various traces it appears that some resistance should/could be measured.

Can somebody confirm or deny the fact that one should measure infinite resistance with all 4 mosfets removed?
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Anyone can answer this question?
Additional info which might help
http://www.bimmerboard.com/forums/posts/136145/
http://www.bimmerboard.com/forums/posts/426626/
http://www.bimmerboard.com/forums/posts/355700/
http://www.bimmerboard.com/forums/posts/355705

shogun
02-07-2008, 10:42 PM
o.k., got reply from Tim in the U.K.:

The problem is that I've never seen a real circuit diagram for the sword. The circuit diagram on the bimmerboard thread is wrong.....very wrong! I would say that there is a good possibility that there will be a resistance between the FET Source and Drain connections when the FET's are not fitted as there will be feedback resistors at the FET Source to sample the output voltage.

It sounds perfectly normal to me.......