hi there, i'm fixing a car amp .. and i just change the transistors IRFZ34.. in the CASE say SEC 818 IRFZ34A and i just replace it for a normal IRFZ34.. when i turn on the amplifier the fuses BLOW!!! why is that.. ??is any difference beetwen SEC 818 irfz34a and irfz34..?? thanks... (i from VENEZUELA)

 

IFR series are mosfets and its highly static sensitive, may be its blown once again because of your static charge from the hand. check for the shortings between drain and source.
If its short replace it once again and see.
Best of luck
bipin

 

Just for your informatiopn SEC is the manufacturers code and the 818 is usually a date code or batch code from when they were produced.

I've seen quite a few mosfets made by SEC but i don't know what manufacturer uses that abbreviation. The make shouldn't really matter as long as the part number is correct.

Maybe something else has failed such as the output transistors or if it's a high power amp maybe something in the DC-DC converter (most car amps boost the 12V upto some higher figure to get more power output to the speakers)

Do you know what part of the circuit is using the IRFZ34's? they are only quite low current devices!

 

hi,

when a fuse blows after replacing a defective part means there's still another culprit lying about the circuit board that you have not noticed. check for burned resistors and leaking caps.

pls. take note that this reply is based on the assumption that you have observed the proper procedure of handling cmos devices.