Trying to repair printer ac adaptor. need help

[pistolpedro]

Hello this is my first post in this forum. this place have helped me repair a couple of things.
but now i need a little help.

After a power surge the printer stopped working, so i took out the adaptor and started testing the leads but i am not getting any readings.

The printer is a canon mp600r. it was quite expensive so i would like to repair it.

so i open it and found there is 3 fuses, one is blown.
i exchanged the blown fuse with a new one but it also blew.

There must be a faulty component causing this to happen.

I have traced the fuse connections and i am ready to measure every component to find the fault and learn some things in the process.

3 big diodes makes me confused, they are the following with the measurement result:
D9: 31DQ/06/7L Reads .200
D10A: 3PHA/20/7D Reads .256
D10B: 3PHA/20/7D Reads .257

I have THIS tester: http://www.ebay.com/itm/TRANSISTOR-...399&pid=100033&prg=1011&rk=1&sd=190821060462&

acording to that tester the diodes are faulty. is it correct? or it is special diodes that gives such readings?

secondly i am confused with the mosfet k3562. i need help to figure out a way to test it. i have made a lab bench power supply from an old atx computer power supply that i can use to test the mosfet with a little guidance.
I have tested it with the multi tester i buy from ebay and i will attach that too.

i will attach pictures of board and keep all of you updated.

thanks for any help i might get!

 

[pistolpedro]

The canon ac to dc adapter:
Manufacturer: CANON
Model Number: K30271
Part Number: QK1-2623-DB01-01

Input Voltage: 100-240V AC 50/60Hz 110VA
Output: 24V === 0.5A 32V === 1.1A
Connector Type: 6Pin White Rectangle 13 x 4 mm
Connector: 6 pin rectangle white flat 1 [ ■ ■ ■ ■ ■ ■ ] 6
Possible pin assignments: (Not sure)
Pin 3, 5 = 32Vdc
Pin 2 = 24Vdc
Pin 1, 4 = GND
Pin 6 = Cont

 

[Sinewave]

What do the diodes read in the other direction? Make sure they're open circuit regarding which way they're biased.

To test the mosfet, make sure you have your body grounded. Set your meter to read ohms and connect the meter negative to the mosfet source.

Then touch the meter positive to gate, this should switch the FET on. Now move the positive lead to the drain, you should see a low reading.

Keep the leads connected where they are and touch with your finger between source and gate. This will discharge the gate and switch off the FET, so you should see a high reading to confirm this.

 

[pistolpedro]

ok here is how the diodes reads in diode mode.
actually when the diodes was in circuit they gave readings both direction.. 1.9 in one and about .200 in the other.
better you look picture then me trying to explain everything in English

then you will see picture of the mosfet k3562..
i did exactly as you described but i am getting weird readings.
firstly the digital meter did not show anything when i test in ohms.
and nothing comes up in diode mode..
but with the analog meeter it shows a reading. but when i touch my grounded fingers between ground and source nothing happens. it already show reading from beginning, it does not change the value by touching the gate with the negative from the meeter..


i had another n channel mosfet i take from my old tv set, that one works with this method with both meeters. but the digital meeter must be set on diode to work.
the old mosfet switched off it when i grounded gate and source with my fingers.



are the diodes and the k3562 bad?