need help with 13001 transistor in Mobile charger.

[Ayazhaider]

Today my mobile charger got faulty.
I tried to check and repair. I found a transistor 13001 does not show any activity while checking with multimeter. I thought it is open (Break) and i purchase 2 new one from local shop.
but when i check that new one with multimeter it also doing same.

My checking method is as FOLLOWING:

I set multimeter on (Alarm / connectivity / diode) testing.

then connect red and black probe on emitter and collector. then reverse. and at last connect base.
but nothing appears in meter display.

Now my question is that is there any other method to check or i have bought 2 more faulty transistors.




The circuit diagram is similar with attached pic.

SORRY FOR BAD ENGLISH :sad:

 

[goldsmith]

Dear Ayazhaider
Hi
Are you sure that that diode in snubber circuit is 1n4007 ? isn't it a UF4007 ?
And are you sure that is a BJT ? isn't that a mosfet ? can you test it ?
Best Wishes
Goldsmith

 

[rfredel]

Hello Ayazhaider,

My checking method is as FOLLOWING:

I set multimeter on (Alarm / connectivity / diode) testing.

This setting is ok.

then connect red and black probe on emitter and collector. then reverse.

If now you don't have any reading on your display the transistor has no short circuit.

Now, test between base and emitter. The reading must show a diode. Do the same measuring between collector and base. Also you must see a diode.

Are both diodes are ok, you transistor is ok also.

i have bought 2 more faulty transistors.

I think you don't buy faulty transistors.

Often the 2 capacitors C4 and C5 lost their capacity. Also check the resistors R7 and R10. Sometimes the get high-resistance. Then the power supply will not start.

I hope it will help you.

Best regards

Rainer


PS: Sorry, if my English is not so good.