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Whaam68 · 23rd Nov 2020, 7:02 pm

Well specifically are these devices testing as good or not?
First the background...around 2012 I built a diy class A kit amp the Nelson pass Amp Camp....one of the first amps I built. I brought it down from its 10 year resting place in a box in the loft on Saturday to use it in the spare bedroom (now my office). All was well and it sounded great. Stupidly I moved a speaker with the amp on and heard a bit of static and the channel driving that speaker died and the heating cooled rapidly. I removed the board from the duff channel and de soldered the two output mosfets and the other mosfet and transistor. I had recently picked up a cheap transistor checker and it is recognising the n channel mosfets. If anyone can confirm the readings seem ok or not it would be appreciated as a start in my figuring out what went wrong. The outputs are IRFP240 the “driver?” Is a 2sk170 jfet and there is a ztx450 transistor.
Thanks
Mike
Mods please move if this is in the wrong section! Thx

23rd Nov 2020, 7:02 pm	#1
Whaam68 Hexode Join Date: Feb 2007 Location: Luton, Bedfordshire, UK. Posts: 457	Understanding transistor tester readings Well specifically are these devices testing as good or not? First the background...around 2012 I built a diy class A kit amp the Nelson pass Amp Camp....one of the first amps I built. I brought it down from its 10 year resting place in a box in the loft on Saturday to use it in the spare bedroom (now my office). All was well and it sounded great. Stupidly I moved a speaker with the amp on and heard a bit of static and the channel driving that speaker died and the heating cooled rapidly. I removed the board from the duff channel and de soldered the two output mosfets and the other mosfet and transistor. I had recently picked up a cheap transistor checker and it is recognising the n channel mosfets. If anyone can confirm the readings seem ok or not it would be appreciated as a start in my figuring out what went wrong. The outputs are IRFP240 the “driver?” Is a 2sk170 jfet and there is a ztx450 transistor. Thanks Mike Mods please move if this is in the wrong section! Thx Attached Thumbnails Last edited by Whaam68; 23rd Nov 2020 at 7:19 pm. Reason: Wrong section?