Canon i850 PSU Trouble

[budm]

Re: Canon i850 PSU Trouble

2SC1741 (look up the spec for it) is a NPN transistor, not sure about the pin out, if you look at it with the flat side facing you, left pin will be E, then C, then B. This is typical pin out for Japanese transistor. There is also a surface moounted transistor with the Emitter leg connected to the Gate of the MOSFET also

[Mad Capper]

Re: Canon i850 PSU Trouble

If it is acceptable to test the SMD transistor at Q203 while on the board and the legs are as labeled in the attached image then this is what I get for that transistor


Red on - Black on
E - B 743
B - E nothing

C - B 730
B - C nothing

E - C nothing
C - E nothing
If I do these last two in the reverse order, i.e. first red on C - black on E, I get a reading that climbs when doing red on E black on C. I don't know if this is a problem or is only occurring because it is still in circuit.