Samsung LN2353H - Bad Power Supply BN44-00158A

[Xlr8r]

Hello,

I have this TV that has a bad power supply. I thought it was just going to be a bulging cap on the output. Replaced all the caps but still no go. So I started checking my voltages on the output and the only thing that is working is the 5V standby. All other voltages are missing. They all show 0V. When I have the PSU in the TV it Cycles on and off... I have since taken it out and jumpered with a resister the standby 5V to the PS_ON to turn on the Power Supply and the Voltage across the large cap comes up to 385V from 190V But still get nothing on any of the outputs. There should be another 5V, 12V, and 24V, but all are missing.

I've researched this board on the forums and other places but can't come across anyone that has had the exact same problem that has fixed it...There is one thread here of someone trying to fix one, but they are still trying to fix theirs as well.

https://www.badcaps.net/forum/showth...ight=LN-T2353H

Not sure what to check next. It has to have something in common with all the voltages???

I have the schematic for the board if anyone needs it.

[multimeter]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

disconnect the inverter,does the 24v come up then when ps_on jumperd?with the mainboard disconnected,it could be dragging all other voltages down.

did you jumper the ps_on too 5vstby and jumper bl_on to its stby voltage?

last time i fixed one of these,rm801 was faulty,and the long ic with lots of pins on it was gone.on the back of that ic,is it me or is there a hole in the back of it?
also check cm602 aswell.

also,disconnect the lvds cable to the tcon,known these to go faulty and cause this problem

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Everything is disconnected from the board...Still no power. The jumper is from PS_On to 5V Standby. CM602 has been replaced with no change. RM801 measures .5ohms out of circuit. No hole in the back of the IC...

[selldoor]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Right in the middle of the board is a red rectangular component - is it a fuse? and if so can you check it first for resistance then the volatge on each side with respect to a ground
screw.

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Yes, the little red guy is a fuse....Fuse checks good and measures 385V on both sides of it.

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Anyone know what kind of voltage I should have on the input of the transformer and then the output?

[budm]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Check the cap CM802 to see if it still show 0.18uF, you need to check it out off the circuit, this is the commonly failed cap.
Do you also get B+ and M_VCC? Another commonly failed is the IC F9222L.

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Check the cap CM802 to see if it still show 0.18uF, you need to check it out off the circuit, this is the commonly failed cap.
Do you also get B+ and M_VCC? Another commonly failed is the IC F9222L.

I should have said this before but CM802 and IC F9222L have been replaced.

B+ = 385V

M_VCC = 19.22V

[budm]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Source resistor RM803 (0.39 Ohms) is OK?

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Source resistor RM803 (0.39 Ohms) is OK?

RM803 measures .7 ohms out of circuit.

[Xlr8r]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Any idea what to test next on this board. It has me stumped good...


Thanks.

[Easky15]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Hi mate, Did you have any joy with this board?? I have the exact same one with what seems to be the exact same problem,

[Jai Electronics]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Hi mate, Did you have any joy with this board?? I have the exact same one with what seems to be the exact same problem,

I had problem with this PSU BN4400158A from Samsung LE23R86WDX, did all dry joints, changed the caps which seemed blown but still did not work changed resistors RM801 and RM803, still no joy so after reading all the questions and answers on Badcaps I took out CM602 which seemed fine but after taking out found found out it was open, changed it and now the TV is working fiine.

This site solved my oriblem

[Amjama]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Hi, i know is an old thread but I have similar problem with my TV : power supply bn44-00158a power supply model. I replaced the bulg capacitors, but no luck.

The voltages fluctuates and not stable. Few questions

I do not see cm602? Nor on the schematic too.

CM855 looks darker, but what is 50v224k_2012?

Removed Rm801 out of circuit to measure and it measures 0.4ohms but schematic says 0.22k? Is this k for tolerance?

I also need to replace cm802 but what is 630v183j? And where can I purchase these components?

Thanks.

Ps: the person that open this thread, did you manage to fix your TV.

[budm]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Can we see good clear pictures of YOUR board, especially the parts in questions?
"Removed Rm801 out of circuit to measure and it measures 0.4ohms but schematic says 0.22k? Is this k for tolerance?" RM801 should be 0.22 Ohms, it shows 0.4 Ohms is due to your meter's leads resistance.

'630v183j' = 0.018uF 5% 630VDC.
'50v224k_2012' = 0.22uF 10% 50VDC

[Amjama]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Hi thanks for the reply, apologies for not attaching the images of the board/component in question, because I have the same board, though it was not necessary. I have now attached the images.

So measuring 0.4ohms is the result of having a standard multimeter, It looks abit burn so decided to remove and currently looking for the component.

In previous comments, people have mentioned Cm602 is this a typo!? I can't find this device in the schematic you attached.

[Amjama]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

I have had problems uploading images, here is the front part

[budm]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

It is CM802 (0.018uF 630V) which is part of the switched 12V/24V power supply, if that cap loses its capacitance then the 12V/24v will be low.
There is no designator for CM6xx for the switched 12V/24V SMPS power supply section they use CM8xx for capacitors. RM8xx for resistors, DN8xx for diode.
You have indicated that the power supply Voltages are unstable, which one? The standby power supply or the switcched 12V/24V?
How about the DCV between the two legs of the main filter cap? Are you getting >380VDC when the PS-ON (PWR-ON) signal is present?
You must also remove ALL those bad brown/yellow glue, they are corrosive and conductive.

[Amjama]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

Hi budm


All my voltages where fluctuating, as the capacitor cm802 and cm855 was dark, indicating a sort of burn and bulged caps. Therefore as a big time amateur with the voltages fluctuates i went ahead and replaced the bulged capacitor and removed cm802, rm801 and f9222l. Now I am struggling to find replacements for

Rm801- 0.22ohms 1W fusible resistor, all I can find is:
0.22 ohm 0R22 0.22R 1W /1 Watt Metal Film Resistor
Will this be good enough as this is not fusible resistor?

Cm802- = 0.018uF 5% 630VDC, all I can find are:
WIMA PET film capacitor, MKP10, 0.018uF, 18nF, 1000v, 1kv,
Or
condensateurs 0,018uF 18nF 1000V 5% Wima FKP1

Although they have higher voltage rating but should be ok, what is your thought and advice?

I have not measured the DCV between the two legs of the main filter cap, when I purchases these new component I will measure this. I know it was a big mistake in removing the components without fully diagnose the problem. I can't put them back as the legs are damaged. Learning from my mistakes ....

Ok I will remove the yellow glue, thanks for the advice.

Before I purchase these components, can you please let me know if they are ok? Thanks

[budm]

Re: Samsung LN2353H - Bad Power Supply BN44-00158A

0.22 Ohms: you can use MOX (Metal Oxide) Flame proof resistor.
the cap 0.018uF cap has to be Metalized Polypropylene type 630V rating minimum, higher Voltage is OK.
For example:
Resistor: http://www.digikey.com/product-detai...0CT-ND/2021740
Cap:
http://www.digikey.com/product-detai...2122-ND/585189