Hi I have a Sumida IV95260 SMPS power supply from a JVC X30 Projector. The initial issue was that the projector wont power on. This is from my friend and hence dont know what was the status of the LED error code. As per him, the Power LED turn on and nothing happens after that.
I thought its a SMPS related issue and found that that the Power supply is not outputting voltage required. I dont have a schematics of the board, and hence made a circuit diagram from the board. I can see the SMPS IC NCP1271 is getting power and is in error state because of the lack of Feedback from the Secondary section. I checked the Primary Section MOSFET and was found to be ok. I dont want to work on the live main power, so, I created a 120V DC power from a 36V using a voltage Tripler to get the board working. I can see the primary section is working ok up till the Mosfet. Disconnected the Transformer to see any shorts in the output and could not find any. Except that the resistance between the 12V rail and ground is 23 Ohm because of 6 parallel 181 Ohm resistors.
Checked the Secondary side by supplying with external voltage to see any shorted components, but cant see anything.
As I can see there is an onboard 5V Generator that supplies power to NCP1271. Shorting two pins at the connector gets that section working, but cant see any reason why the SMPS is not working.
Parts changed so far:
Opto-couplers
NCP1271
Primary side Switching Mosfet.
Has anyone worked with this model SMPS. Just need some guidance to see if am missing something to get this SMPS enabled properly.
SMPS-min.pdf (1136.46 kB - downloaded 150 times.)