Samsung HW-E450 Soundbar

Does it use a wall-wart transformer/power supply?

I'd start with that.

No it does not use a wall wart, internal power supply with soldered in fuse which is not open circuit.

Have you got the service manual? If not, it's downloadable here:

The troubleshooting flowcharts in the manual assume you're going to be swapping out entire boards, but at least there are schematics to help track things down to component level.

If you've confirmed that the fault is on the SMPS board, I'd check the electrolytic capacitors (be sure to discharge them before touching anything on the board) and high-wattage resistors (RS801, RA808) first, as these are possible failure points that could be tested without working on a live circuit.

The safety guide in

is extremely useful, particularly if you do end up having to investigate the SMPS while it's powered up.

R

Thanks very much for the info re service manual/schematic and the repair faqs. I will check them out, I know I have 380 volts dc at the bridge rectifier output. D