Samsung LN46B550 No Startup

[Syryll]

I've got this Samsung TV laying around that doesn't work.

Standby light comes on when plugged in, as it should. When I attempt to power the TV on, I get the power-on sound the TV makes, no backlight and the standby light flashes 5 times and goes out.

I've read that Samsung TVs will power on the backlight if CN802 is disconnected when applying mains power. This isn't happening with this set. Not sure if this particular one has that "feature," but I figured it could be of note that I tried it.

Two big caps in the center read 157.7 at the legs with TV in standby, 151.5-7 when powered on.

CN802 readings:

DET_5v: 0v
INV ON/OFF: 5.15v
13Vm: 12.99v
13Vs: 13.04v
5.3v: 5.17v
STB 5.3v: 5.2v
POW ON/OFF: 1.18v

CN1806 readings:

VCC 12v: 13.00v
LD1: 12.76v
LD2: 12.76v

The power supply is marked as model IP-281609A

How should I proceed?

[budm]

Re: Samsung LN46B550 No Startup

"Two big caps in the center read 157.7 at the legs with TV in standby, 151.5-7 when powered on." The PFC Voltage booster circuit is not working.
Check all the diodes in the section between the two big heatsinks, especially the DP805, 806 (I cannot read the numbers clearly).
BTW, the board does have built-in pull-up resistors for testing the board when the cable between the power supply and the main board is discoonected.

BN44-00265A
http://www.shopjimmy.com/samsung-bn4...upply-unit.htm

[Syryll]

Re: Samsung LN46B550 No Startup

I checked all the diodes on the board. DP805 and 806 are fine. The only one that tested bad was DM810, which resides under the legend for CM802.