irf540 and irf9540 can these be tested with a dmm

[homertooties]

Hi everyone can these hexfets be tested with a dmm to see if they are bust or no .cheers

 

[mitwrong]

IRF5XX TO BE TESTS

Homer:

First of all, I want to Know what parameter of the FET you wanted to test by a dmm, usually a dmm can only define out N channel or P channel, Gate junction failure, other than this, I don't think a dmm can do any further unless your dmm is a special made.

Give me more info. so that we can help!




BEST REGARDS

 

[clem_o]

I think homertooties refers to 'gross functionality'...

Cheers!

 

[homertooties]

hexfets

Hi there thanks for replys i just wish to test them as in function,so i can determine whether i have to replace them or not as amp is getting a pain in the ****.............🙂

 

[richie00boy]

Test drain-source and source-drain with an ohm meter. whilst gate and source are shorted. If short both ways then it's broken. The body drain diode will show some continuity source-drain depending on your meter, and setting to diode test will fully test this, but this is not necessary.

 

[homertooties]

hexfets

Hi there many thanks for reply i shall do that test

 

[homertooties]

hexfet test results look good

Hi all i have tested these hexfets and the readings are all done with diode test on my Di -log DL 293 Meter.

irf9540 (1) Gto S Shorted - lead on g and s + lead on D
reading 752 ohms reversed no reading

irf540 (2) G to S Shorted + lead on g and s - lead on D
reading 516 ohms reversed no reading

The above two fets were getting very hot when in amp.

irf540 (3) G to S Shorted + lead on g and s - lead on D
reading 518 ohms reversed no reading

irf9540 (4) G to S Shorted - lead on G and s - lead on D
reading 827 ohms reversed no reading

i am guessing these fets are fine and the trouble is in the pre and driver stages............
Anyone agree please let me know what a great forum this is...😀 😀 😀

 

[richie00boy]

Yes a bad device would show very low resistance at least one way if not both.

 

[homertooties]

further testing

Many thanks Richie00boy i shall play further with the tough dog,i will update later