Been working on a half dead SMPS board for quite a while now. Think I may have found a problem but need help making sure I am properly understanding the functions of some of the pins on this IC.
The first Question is regarding pin 16 which is 5.1V REF. At first I thought this was a required reference input. However, I believe that was wrong. I now believe it is supposed to be a 5.1v output reference to be used by other parts of the circuit. However, I am reading 13.3 volts on that pin and I believe it is a bad chip due to this and needs replacing.
Also, regarding pin 10 which is the shutdown pin. I believe this is an input as internally it goes to the base of an NPN? Originally I was getting over 7 volts on this pin. I adjusted a preset which got it down to .7v instead. It is not supposed to shut down the chip until .9 I believe? I think that is too close to call as my meter is not NIST calibrated etc.
All input is appreciated. Mostly, I just want to know if I am right about the function of the pins.