Determining a faulty capacitor

[speedypro]

Im working with one of these amps: no power. Turns out a faulty transistor and blown fuse. Replaced both but still no power. On further testing, red circle is damages. How to know what to replace with? Yellow oval is the transistor ive replaced. Transistor was a NDF04N60ZGOS-ND.

[budm]

Re: Determining a faulty capacitor

So that C105 snubber cap shorted out too beside the MOSFET?

[keeney123]

Re: Determining a faulty capacitor

So where is the brown wire connected to one the board?

[budm]

Re: Determining a faulty capacitor

BTW, that big MOX resistor for the Source pin of the MOSFET is still showing <1 Ohm?

[speedypro]

Re: Determining a faulty capacitor

So that C105 snubber cap shorted out too beside the MOSFET?

Yes. On MM is show up as DISC or DESC, not sure but it's gone.

So where is the brown wire connected to one the board?

It's just for the fuse. Original fuse was a 2a. Now Im temp using a 1amp.

BTW, that big MOX resistor for the Source pin of the MOSFET is still showing <1 Ohm?

That resistor is fine to be honest. I think it's showing 3K, Im not at work to confirm. But Im pretty sure it's ok.

[budm]

Re: Determining a faulty capacitor

I do not understand what you mean, Disc. Bottom line is the cap shows resistance reading or not. So what resistance do you get on the cap?

[speedypro]

Re: Determining a faulty capacitor

I do not understand what you mean, Disc. Bottom line is the cap shows resistance reading or not. So what resistance do you get on the cap?

I'll let you know when I'm at work later.

[budm]

Re: Determining a faulty capacitor

That power MOX resistor if I am correct, it should be connected to the Source pin of the MOSFET, when the MOSFET shorted out it will also cause the resistor to go open citrcuit. It should be very low resistance of less than 1 Ohm.

[speedypro]

Re: Determining a faulty capacitor

That power MOX resistor if I am correct, it should be connected to the Source pin of the MOSFET, when the MOSFET shorted out it will also cause the resistor to go open citrcuit. It should be very low resistance of less than 1 Ohm.

Yea it was burnt. I part of the outer part was blown off. I'll confirm in 5hrs time.

[speedypro]

Re: Determining a faulty capacitor

So that C105 snubber cap shorted out too beside the MOSFET?

No resistance for cap. Resistor has about 16Meg Ohms (tested in circuit).

[CapLeaker]

Re: Determining a faulty capacitor

that resistor is FUBAR

[speedypro]

Re: Determining a faulty capacitor

that resistor is FUBAR

LOL! Ok so what about that cap?

[stj]

Re: Determining a faulty capacitor

probably fine.