Samsung LN52C530 Backlight Strobing

[Ltank]

Backlights intermittantly strobe at a fast rate. It flickers fast every time it is turned on or off, other that that it is not inconsistant and intermittant.
The set has a BN44-00343B P.S. The board that connect to the backlights look fine. I am assuming that the PS voltage from CN801 is fluctuating.
My old Pomona 40k HV probe does not read the voltage when backlights are light up. What is best a to read the HV from inverters. The 40K stand alone probes dont seem to be accurate on the low end . The analog meter maybe better to dhow fluctuations if not too fast. What are the better probes reasonably priced to connect to a Fluke 87 Multimeter? Suggestions?
The Backlight Driver board dont show any damage. I dont think its a backlight dim pin from M.B. to P.S. voltage? I am almost postitive it the
P.S./ Inverter.
Thanks
Ltank

[Ltank]

Re: Samsung LN52C530 Backlight Strobing

Alot of places list removing Jumper JP852 as the fix for the problem? Why? Is this a legitamate fix? I can get another but a used one will do the same latter. Does anone have a schematic for this Power Supply? What does JP852 do when installed vs removed?
Several models are plaqued by this problem. Any Ideas?
Thanks
Ltank

[johnboy1313]

Re: Samsung LN52C530 Backlight Strobing

I can't remember the jumper number, but it is a legitimate fix. I've done it myself

[Ltank]

Re: Samsung LN52C530 Backlight Strobing

This may fix the complaint but bypassing the safety? I can't do this with a clear conscience. Does anyone have a Schematic? I could not find one. Online people want 20 to 75 bucks. But do they actually fix the complaint or just cut JP852?
Thanks
Ltank

[Ltank]

Re: Samsung LN52C530 Backlight Strobing

Well this Tv came back. This is my 1st call back in almost a year. Guess thats pretty good. Set only has standby power according to the customer. Waiting fo him to bring set back in. Just trying to get a heads up on the problem. Would Cutting JP852 cause this problem over time? It has been over a month. The board are about 85 bucks used if you can find them ot 180 new.

[johnboy1313]

Re: Samsung LN52C530 Backlight Strobing

I cut the jumper on my cousin's set over a year ago and it's still going strong.

[nuala]

Re: Samsung LN52C530 Backlight Strobing

CUT JUMPER JP852 PER SAMSUNG ON POWER SUPPlY PCB

[awyatt2]

Re: Samsung LN52C530 Backlight Strobing

I just posted a fix on this set almost 4 hrs constant no flicker and the jumper isn't cut.

[awyatt2]

Re: Samsung LN52C530 Backlight Strobing

here is the fix, 4 sm resistors are breaking down dropping the pfc voltage mine was around 350v and should be 390 there are four sm resistor on the back side of the power supply labeled rp802,rp805,rp807, andrp810. remove these 4 1.5 meg resistors and insert a 1/2 watt 6meg ohm resistor, I went to the cap to the beginning of the line as the pic shows. been playing all day and hasn't flickered once and voltage is steady at 390v.you aren't bypassing a safety feature here the jumper is intact and functioning.

[awyatt2]

Re: Samsung LN52C530 Backlight Strobing

this fix is still working 8 months without as much as a flicker. just wanted to repost a success.

[budm]

Re: Samsung LN52C530 Backlight Strobing

here is the fix, 4 sm resistors are breaking down dropping the pfc voltage mine was around 350v and should be 390 there are four sm resistor on the back side of the power supply labeled rp802,rp805,rp807, andrp810. remove these 4 1.5 meg resistors and insert a 1/2 watt 6meg ohm resistor, I went to the cap to the beginning of the line as the pic shows. been playing all day and hasn't flickered once and voltage is steady at 390v.you aren't bypassing a safety feature here the jumper is intact and functioning.

That is the correct way of fixing the problem due to low PFC Voltage, cutting the jumper will remove one of the protection circuit.

https://www.badcaps.net/forum/showth...highlight=J852

[saddle_au]

Re: Samsung LN52C530 Backlight Strobing

Please don't use just one resistor for the replacement of the on-board resistors. You are dealing with very high voltages and should use a string of them to make up the 6Mohm to limit any breakdown that might occur. Unless you have specialized parts, please use a minimum of 3 with nearly the same value (2M2, 2M2 and 1M5 would probably work well there, chuck in another 100k if need be).

[Bob609]

Re: Samsung LN52C530 Backlight Strobing

resistors fix was a revelation to me - never thought resistors would breakdown. Thanks so much for this suggested fix - fixed my TV for cheap. used 3 2 meg 1/8W after cutting the trace to bypass the 3 bad SM ones.