CR6842S ACDC HELP

[franksterb92]

I Reverse Engineered the WX-DC2412 ACDC Module AND made  PCB containing the circuit of this module plus some regulators but i cannot get it to work ive tried different start up resistors and capacitor values kind of stuck and dont really know what to do now any help would be greatly apricated ive attached the schematic of the acdc section

[aliarifat794]

Please check if you have mistakenly reverse polarised any components like the diodes, capacitors etc.

[franksterb92]

Unfortunately I have done that does anyone know a way to make sure the chip is starting up it seems like it won't start

[floobydust]

Post voltage measurements, at least on the IC. The ones on your schematic are from a working PSU and not helpful.
Do be extra careful as the primary HV filter cap will be holding a charge if there is no load or bleeder resistor present. Shock hazard.

[franksterb92]

 Ok I will wen I get home and your right those voltages are from working one but from my troubleshooting  the voltage at the vdd pin of ic is almost the same as a working one and the Vin pin the same although on my pcb it seems to be picky of the capacitor value at c4 but not picky on the module itself  like the voltages will be stable with 0.1uf 100v cap but not 100uf 100v cap don't make any since

[franksterb92]

from testing I've fond that R7 is open I'm waiting on replacement hopefully this is why my board isn't working cause this project is driving me crazy but I've learned so much along the way

[floobydust]

If current-sense resistor R7 goes open, this is usually because it's a fusible/flameproof part that got overloaded from a mosfet shorting out. It damages the IC and new mosfet if you are not careful to check those parts too.
A dim light-bulb tester to power this is also a good idea to save on fuses and smoke. Even a 25W lamp is all you need to power it up with no load.

[franksterb92]

it works now i got the replacement part and replaced last night and it works wow how i way over complicated this fault in my mind as i never put together a smps pcb before lol oh well i learned so much about smps design