Samsung LE26A336J1D dead, no power, PSU failure BN44-00208B

[Chungalin]

PSU schematic available at ElektroTanya under BN44-00208A, looks the same as BN44-00208B.

This one doesn't have any voltage at Secondary. It has 320V at Primary capacitor (230VAC mains area). I notice that ICB801S (Fairchild FSQ0365RN) isn't powered at pin 2. Then I see that RB806 (10Ω 2W, fuse?) is open. No signs of sparks or violence. No bad caps, normal ESR. No shorted components at primary. FSQ0365RN doesn't seem short.

Does anyone have encountered this same symptom before? Is it wise to just replace RB806 and "see what happens"?

[Chungalin]

Re: Samsung LE26A336J1D dead, no power, PSU failure BN44-00208B

Looks like I’ll have to try luck...

[Chungalin]

Re: Samsung LE26A336J1D dead, no power, PSU failure BN44-00208B

I’ve eventually replaced RB806 with a normal 10Ω resistor and everything works apparently fine. I’ll test it for a few days to see if it stands.

I’m quite reluctant to be happy with a repair like this, since I cannot find a rational explanation on why RB806 got fused, while main fuse is intact.

On the other hand, replacing a fusible resistor with a normal one (since I don’t know actual specs of original resistor) doesn’t give me peace of mind.

[budm]

Re: Samsung LE26A336J1D dead, no power, PSU failure BN44-00208B

The resistor should be at least the Flame proof MOX (Metal Oxide) type. You can check the Vdrops on that 10 Ohms resistor so you can calculate the current draw, sometime the resistor can be replaced by the fuse instead.

[Lipti]

Re: Samsung LE26A336J1D dead, no power, PSU failure BN44-00208B

The resistor should be at least the Flame proof MOX (Metal Oxide) type.

I've spent hours in searching for the best replacement of RB806. I don't want to use a spare part with lower quality/fuse capability, as the old one got an open circuit and the replacement shouldn't go on fire or cause other damage if the problem still remains.

I've found fusible resistors but they are wirewound. You talked about "at least MOX type", is wirewound better?

Do you know what exact type the original RB806 is? Wirewound, MOX, or ...? 2 Watt at 70°C?

Shall resistors be especially named "fusible" or are "standard" flameproof resistors the same?

Thank you very much in advance, this specific topic of fusible resistors is new to me!