Hello Hila ANGALIKIANA,
Yes I know : none of the IC's I mentionned has 9 pins. So it will require some sorcerer tricks to use one of those as a replacement for the dead PWM controller.
Luckily, the PS housing gives some clues about the printer's power requirment :
24 VDC 0.3 A
32 VDC 0.45 A
1) The easy way
This Canon power supply matches the requirements.
Might be a different form factor but OK, it should work.
https://www.ebay.co.uk/itm/2539611430682) A bit steeper
24 VDC power supply :
https://www.reichelt.de/de/en/switching-power-supply-15-w-0-62-a-24-v-snt-rs-15-24-p137083.htmlFor 32 VDC, start with this one :
https://www.reichelt.de/de/en/switching-power-supplies-36-w-36-v-1-a-mw-lrs-35-36-p202957.html followed by a LM317 regulator + heatsink
For 32 VDC output R1 = 470 Ohms
R2 = 11562 Ohms (10k fixed resistor + 2k2 adjustable resistor)
https://www.omnicalculator.com/other/lm317Use a vanilla multimeter to adjust the output voltage to 32 VDC.
3) The hard way
A closer look to the solder side of the PCB gives some information about that weird PWM IC (see attached picture)
The +320 VDC and 0V rails are easy to find.
For the PWM controller :
Pin 3 GND
Pins 8, 9, 10 High voltage switch drain connexion
Pin 1 must be the source connexion of the high voltage switch, because R104 (probably a very low value) seems to act as a current shunt towards the 0V
Pin 6 is some kind of startup power supply because it's rectified from the mains with 2 x 3k3 in series
Pin 4 is probably the feedback signal coming from the optocoupler (it's not easy to follow the tracks under the SMD parts). There are also very small (0402 ?) SMD parts going from that track towards 0V.
Pin 2 is the IC's power supply, coming from the AUXilary primary winding through 2 x 5,1 Ohms, and an SMD diode. There's also an unknown SOT-23 SMD part in the path (I marked it TR?).
Of course, selecting a 'compatible' PWM IC is far from easy and the magic smoke might show up.
One additionnal difficulty is that we don't know the switching frequency of the original part. The ferrite transformer has of course been manufactured with a precise primary inductance, that matches with the PWM IC switching frequency.
And of course, all of the electrolytic capacitors must also be replaced with new ones.
Update #1 & #2 & #3 : typos