Samsung has 5v_STBY but no B13

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

What happened was it wasn't grounded then slipped and shorted out, prolly damage to the powerboard as well, any time the powerboard is powered while on the tv it needs to have the ground screws in, I put them all in while testing, very important when working on plasmas too.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

I don't think the powerboard is damaged. I measured +5v, +13V correctly and instead of 165v at the BL output, I got 185V but I believe this is because the LEDs are all open circuit, hopefully...

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

It's kind of amazing how absolutely every led blew out, strange indeed.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

It's kind of amazing how absolutely every led blew out, strange indeed.

I know it, but I've always tested them with my multimeter in DIODE test mode using the small bare copper pads left and right of each led (trying both polarities) and in this case I got ZERO light out of ZERO leds....

[R_J]

Re: Samsung has 5v_STBY but no B13

I know it, but I've always tested them with my multimeter in DIODE test mode using the small bare copper pads left and right of each led (trying both polarities) and in this case I got ZERO light out of ZERO leds....

I doubt they are all open, once one opened, there would be no path for the current to damage the others, try using a 1.5v battery to light one of them and see if that works.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

I doubt they are all open, once one opened, there would be no path for the current to damage the others, try using a 1.5v battery to light one of them and see if that works.

I totally understand, it'd be very unusual, I was thinking maybe the output voltage during the shortcut was to high that it was able to jump over the already open LEDS (inside them) and keep traveling across the whole string.

Anyway the LED string (as a whole) are damaged as I kept measuring 185V at the BL output while the LEDS were off with a extremely dim remain of light from one/some of them, as I was seeing it from the chassis side thru some of those holes in the chassis

The new leds will be in my mailbox today so I will check later on
Thanks!

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

You must have a local supplier, that's very quick shipping.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

You must have a local supplier, that's very quick shipping.

It was on AliExpress but probably shipped from a country within Europe

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

Nice, sometimes I get them from ebay to get them faster, about 2 to 4 days rather than direct from china but can cost more, like about 10 dollars more.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

Ok, update on this.
No luck. I installed the new led strips. Same thing. I guess I failed at correctly testing the old led strips....
They still flicker extremely dim. I get 228V at the LED BL capacitor so it looks like it biulds up voltage but it doesn't fully get to the led strips
The TV somehow notices this as the stby led keeps flashing.

What to try next??

Thanks!

PD: Im attaching a close view of the BL section of this PS (both sides)

[edugimeno]

Re: Samsung has 5v_STBY but no B13

OK resistors R9151 & R9152 appear to be open on my multimeter, they show 2R?0 probable 2Ohm resistor in parallel so 1Ohm total. Does this make sense with my issue?
These resistors seem to feed the high voltage from the BL capacitor to the led strips

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

it's a 2 ohm isn't it, if so reading should be 1 ohm.

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

Is there a problem with that board? it looks like the solder melted and ran all over, strange.

[edugimeno]

Re: Samsung has 5v_STBY but no B13

Is there a problem with that board? it looks like the solder melted and ran all over, strange.

In what part do you mean? There was a shortcut that blew something, hopefully only these 2 R

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

In that area you have highlighted it looks like the solder melted and ran over to the other components, can't recall seeing a powerboard that looks like that.

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

Here's another thread on a BN44-604F, looks like there's a schematic there: https://www.badcaps.net/forum/showth...ight=UE32F4000

[R_J]

Re: Samsung has 5v_STBY but no B13

OK resistors R9151 & R9152 appear to be open on my multimeter, they show 2R?0 probable 2Ohm resistor in parallel so 1Ohm total. Does this make sense with my issue?
These resistors seem to feed the high voltage from the BL capacitor to the led strips

The resistors are open, that is why the backlight voltage is high should be around 146v not 228v

[edugimeno]

Re: Samsung has 5v_STBY but no B13

Here's another thread on a BN44-604F, looks like there's a schematic there: https://www.badcaps.net/forum/showth...ight=UE32F4000

Thanks but I had already checked that thread and the schematic they shared has nothing to do with this board

[edugimeno]

Re: Samsung has 5v_STBY but no B13

The resistors are open, that is why the backlight voltage is high should be around 146v not 228v

Ok I went to the shop today and bought a regular size 1R0 5% resistor. I guess a normal 1/4W resistor stands several times the power a small SMD resistor can handle

Also I guess I should have got a more accurate precission one, more than 5%, as this resistor is probably used to measure the current flowing thru the LED strips but 5% is all they had....

Will try it tomorrow

Thanks

[nomoresonys]

Re: Samsung has 5v_STBY but no B13

LOL, just saw it at a glance, I have no idea how a rogue schemo got into that thread.