Good day EEV blog members,
I am a long time lurker here, but decided to sign up, as I am in dire need for some technical info on a specific PSU that I have a nightmare getting repaired.
The supply in question is a SBGD-200-3HP. This is used in Proscan Tv’s and a lot of clones as well
The TV model in question is a Proscan 32LA30Q , but was sold here in SA under the Logik brand.
The problem was originally a blown mains fuse, after a thorough check I replaced all the electro’s as they were High ESR. I also replaced a 18N50 FET and adjacent 9.1 Volt zenner diode, that had given up the ghost. All other semi’s that I could test, were within spec.
The problem now is that with power supplied to the circuit, I do not get any output at all.
Scoped the drive to the 2 mosfet driver transistors and there was no drive signal coming from the smps controller IC. And this is where my problem lies. The manufacturer of this board decided to remove the numbering on the IC. I tried online to find any info, but was unsuccessful . The IC in question is a 16 pin DIL chip. On the bottom of the chip is a stamped marking “China 30”, but that is it. On the board it is marked as U3.
Does anybody have any info on this chip or maybe a schematic of this supply. I would really appreciate any help/info coming forward.
Thanks guys..