UN55D6000 Blinking Standby Light

[mmartell]

Re: UN55D6000 Blinking Standby Light

I don't understand how the Main board can keep the PS alive because I certainly can't do it manually. I've jumped 5vsb to pson, blon and epwm in different combinations. Assuming a new main will fix this wtf is the main sending out to the ps that I can't simulate ?

[budm]

Re: UN55D6000 Blinking Standby Light

You can tell first if the PS_ON is active LO or active HI. Disconnect the cable between the power supply board and the main board, then check the DC voltage on the PS_ON pin and chassis ground, then check the DC Voltage on the main 450VDC filter caps to see if the PFC Voltage booster will kick which then you will have about 370~400VDC at the two legs of the cap. Report the reading.
The PFC Voltage booster should cause the voltage on the cap to go up by either applying the voltage to PS_ON pin or ground the PS_ON pin, one of those should activate the PFC.

[mmartell]

Re: UN55D6000 Blinking Standby Light

Active high.

Disconnecting the cable to the main board and leaving pson floating (or high) causes the problem. Grounding pson gives solid 5vsb and 170v at main filter cap.

Pson floating OR hooked to 5v causes voltage at filter cap to rise to about 388v and then RISE to over 400v and all outputs drop to zero then the cycle starts again. Voltage at main filter cap never falls below 388v

[mmartell]

Re: UN55D6000 Blinking Standby Light

Ordered a main board, will be here shortly. Will update soon.

[mmartell]

Re: UN55D6000 Blinking Standby Light

Replacement main board came in. With everything plugged in the standby light is lit steady and the PS is silent. Seems like it's ok in standby.

When the power button is pushed the light begins to blink and the PS goes through its cycling again. Seems like a had a bad main board AND bad power supply. (lightning ?) I still cannot get the backlight to come on.

I need help to troubleshoot the power supply. I measured the voltage at the power ic (negative lead on negative leg of main filter cap) and its at about 12v, rises slightly to 12.5 when the supply is energized. I'm lost at tracing this out so I need some instruction on where to measure to see what's going on.

[mmartell]

Re: UN55D6000 Blinking Standby Light

Anyone know what the "sync" pin is for on some samsung power supplies ? I'm trying to jerry rig a different supply to help isolate fault.

[tom66]

Re: UN55D6000 Blinking Standby Light

Sync is probably for backlight to stop it flickering in time with video (keeps it in sync with the video.)

[mmartell]

Re: UN55D6000 Blinking Standby Light

Will the average supply start up (secondary voltages) without the backlights or inverters connected ?

[tom66]

Re: UN55D6000 Blinking Standby Light

Ones with 24V inverters will -- others MIGHT but it cannot be guaranteed.

[mmartell]

Re: UN55D6000 Blinking Standby Light

Murky results (!) This supply is from an lcd with ccfl backlights so 24v inverters. Same thing happens - power cycling. Can't seem to create a solid test or conditions to say one way or the other which component has failed. *Frustrated*

[Ltank]

Re: UN55D6000 Blinking Standby Light

What voltage is needed to light up the Less? Can another PS be jumped to light them and beasure the current? Just trying to see what part if any actually works.

[mmartell]

Re: UN55D6000 Blinking Standby Light

It says 330v on the PSU for the connector that goes to the led's. Only four wires, two of which are connected together on the underside of connector. So I guess it's one in and one out.

[wreksta]

Re: UN55D6000 Blinking Standby Light

Mate just the power supply and led plugged in should fire the lights

try it maybe bad led lighting module

[mmartell]

Re: UN55D6000 Blinking Standby Light

Nope doesn't fire the lights, just cycles the power. With my DMM I can't be sure how high the voltage gets before it shuts down and does it again. Maybe the voltage never reaches critical voltage enough to light the led's even.

[tom66]

Re: UN55D6000 Blinking Standby Light

What DMM do you have?

[wreksta]

Re: UN55D6000 Blinking Standby Light

Strip in down check led module just a thought

or panel ribbons for burns of corrosion caused by cleaning the panel incorrectly

using multi meter set to continuity test each of the led's they will light if they dont you found problrm

[mmartell]

Re: UN55D6000 Blinking Standby Light

A DMM will power an led ? Easy check then

[tom66]

Re: UN55D6000 Blinking Standby Light

Not all DMM will power white LED. I have a B+K 2709B which will do the job, nice glow from LED at a few mA, but a couple of cheaper meters I tested did not do the job.

[mmartell]

Re: UN55D6000 Blinking Standby Light

Got this from a friend a long time ago for some money he owed me. He's an electrician.

[tom66]

Re: UN55D6000 Blinking Standby Light

You will just have to try and see. Most 2000 count meter (max reading 19.99V, etc.) cannot drive white LED, max output around 2V. In which case you can use a coin cell and wires to test white LEDs.