| Electronics > Repair |
| ultrasonic cleaner MH-060S, replacing transistors [fixed > broken again] |
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| wraper:
--- Quote from: htm on August 09, 2024, 07:46:14 pm ---@fzabkar Afaik, the C3320 has pin layout: 1(B) 2(C) 3(E) The diode tests show: BC black on 1, red on 2 = OL red on 1, black on 2= OL CE red on 2, black on 3 = OL black on 2, red on 3 = 0.488V BE red on 1, black on 3 = OL black on 1, red on 3 = OL --- End quote --- It's an N-channel MOSFET, what you're measuring between pins 2 and 3 is an intrinsic body diode. Tester detects is as a diode probably due to high gate-source threshold voltage. |
| htm:
@wraper I tested it. Indeed! The MOSFET is changing from Off to On from 4.1V to 5V. But why didn't the Component tester see it as a MOSFET? aren't most mosfets switching in that area |
| wraper:
--- Quote from: htm on August 09, 2024, 10:09:14 pm ---@wraper I tested it. Indeed! The MOSFET is changing from Off to On from 4.1V to 5V. But why didn't the Component tester see it as a MOSFET? aren't most mosfets switching in that area --- End quote --- Most modern ones have lower VGS(TH). Your tester probably cannot supply enough voltage or measure above some value below it. Or maybe its firmware has some quirks. I wouldn't outright trust what such testers automatically detect. |
| htm:
Today i finished replacing the defective diodes and the 4 transistors. On both boards 1 transistor seemed ok, but i replaced those as well, just in case. I rather have them all be the beefy BUV48A :D Did a testrun of a minute, and.. :phew: :-+ Thanks for all advice! |
| htm:
:palm: .. he used it about 3 times, and then it quit on him again. i'll take another look at it, to see if the same thing happened again. |
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