[rca2000]

Ok. I took a look at this chip. I have a "typical application" diagram to go by. Yours MAY be a bit different...BUT the functions WILL be the same.

pin 1==should have full hot B+ on it--as it is the drain pin--the one going to the transformer. Measure to HOT gorund.

Pin 4--the chip B+ line.If it is Near 0--measured to HOT ground (as are ALL voltages on this IC.). either the chip or something erxternal is loading it--likely that optocoupler. It should measure at least a few volts to hot ground--when the chip is running. There does appear to be a "start up" resistor on it. if it was OPEN...NO start and no power up. The strat resistor will be a high-value one--100K or higher--and come off of the HOT B+ from that cap in some way--to pin 4. If it DOES show 0..unsloder that pin and re-check. If it THEN shows a decent voltage...the chip IS VERY likely bad. If it does NOT come up when unloaded...a diode or that optocouplwr is loading the line down. After the chip is up and running...a diode form the feedback line THEN supplies the chip with this voltage and the "start voltage" is bypassed.

Pin 2.. Source... goes to hot ground through a current sense resistor. if the chip was in over current mode..it will mute oscillation to prevent damage. But since you have nO power or squealing or chirping noise..likely NOT the issue. Just measure it to hot ground with an ohm meter and see if it is very close to zero ohom to ground.

Pin 3--Ground. Should also be zero ohms to hot ground.

Pin 7--over current protection. Shares part of feedback ckt and voltage developed from pin 2. . Likely will NOT show any voltage--since the chip is not running.

Pin 5..feedback pin. This is used by the chip to know if it is producing enbough output. it will be connectoed ot the HOT side of that optocoupler. WHen running...there should be a few volts on it--but with it dead...likely NONE

Pin 6..soft start.. Likely will not show anything with the chip not running. It goes through a cap to ground to allow the SMPS to start "gently".

THIS should give you an idea. I would bet..either your chip is bad..or that optocupller is bad (amybe BOTH of them), or a zener diode in the ckt is shorted. Check around the optocoupler and feedback pins for any diodes there and see if any are bad.

CHip is NOT overly expensive on Ebay--new. $16 INCLUDING ship..from FL.