Samsung LE32R88BD/ BN44-00155A

[swhatszup]

Re: Samsung LE32R88BD/ BN44-00155A

Hi Sordids999,

I don't see any pictures?

Regards,
Armand

[selldoor]

Re: Samsung LE32R88BD/ BN44-00155A

You have it wrong Sordid and we need to see pictures of YOUR boards so we can look for problems on them. Good clear in focus jpgs up to 3mb straight on of each board back and front posted using manage attachments

[sordids999]

Re: Samsung LE32R88BD/ BN44-00155A

i have what wrong i thought he posted asking to have his board repaired so i replied telling him to post some pictures ?

[selldoor]

Re: Samsung LE32R88BD/ BN44-00155A

Ha ha sorry missed a comma out it should say
You (swhatzup as the last poster ) have it wrong, Sordid and we need.............

[johnbinsc]

Looking for source for RM801 fusible resistor 0.22 ohm 1 W

Hi everyone,
I just fixed a BN44-00192A power supply board for a Samsung 32 inch LCD TV in great part relying upon the collective wisdom of this forum, so thanks very much!

In my case, the fusible resistor RM801 was blown. This is the fusible resistor that connects and protects the primary line upconvert circuit from a short in the main switching supply circuit.

I have not been able to find a source for a suitable replacement for RM801, which is supposed to be a 0.22 ohm, 1W fusible resistor. Digikey has a listing for a Yageo part with these specs but no stock and a 5000 piece minimum. Bourns has a line of fusible resistors, but they don't go below 4.7 ohm.

So, can anyone point me to a supplier for a suitable RM801 replacement? Or does anyone have a spare (or two) they would be willing to share at cost? (I hope I am not breaking forum rules here. I don't think badcaps sells these.) Please help guys, you have to save me from this:

(See attached image file.)

Yes, that is 5 x 1.0 ohm 0.25 W regular resistors in parallel. Ugly, but the power supply works.

A few comments on this repair for the record:
1) There were a few bad caps, but they probably didn't cause the failure.
2) All the glue was brown and was definitely traced/burnt in the vicinity of RM801 and the nearby small blue cap CM810. I believe this was the cause for the complete failure. I removed all of the glue on board. Fortunately no damage to the circuit board in this case.
3) Cleaning up the glue, replacing RM801 and a few of the cold side large caps and the TV is working again. There were no blown semiconductors or other components.

[HintOfLime]

Re: Samsung LE32R88BD/ BN44-00155A

Hi everyone,

I too have been struck with the BN44-00155A power supply issue. I've read through the whole tread as well as any other resources I can find online. My electrical engineering abilities are fairly limited, and honestly I don't feel comfortable inspecting the board while supplying power to take output measurements yet. I thought I would at least share my the symptoms of my board and a few things I was able to spot as potential problems in case someone else spots similar on their boards. I had some trouble finding high-res pictures of the board for reference, so I'll provide the ones I took in case anyone else is looking for something to compare against.

Suggestions are welcome, but considering the age of the TV and the likelihood that I'd need to replace all the capacitors, the resistor, and then at least one SMD component, I fear this looks like a 'rabbit hole' scenario that is almost certainly beyond me.

---------------------------------------
Symptoms:
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Samsung LCD TV will not power on. Standby light flashes when power button is pressed.

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Observations:
---------------------------------------

The resistor at RM801 is visually damaged.

The top and glue holding thermistor (5D13) at NT811S is damaged and discolored. (I removed some of the glue to read the component ID.)

There is a suspicious dark spot on the front of the board near JP840. On the back of the board, the area around RM810 is darkened and traces display a rainbow-like shimmer.

---------------------------------------

[Ecorecycler]

Re: Samsung LE32R88BD/ BN44-00155A

Hi,

I'm having issues with this board too. I found warming the capacitors up near the connector to the logic board got the TV working. I bought 5x 25v 470uF capacitors and 5x 2200uF 25v capacitors. All low ESR. The minimum order was 5 and it was all I could afford at the time.
I replaced CM858 with the 470uF and CM852, CM853, CM856 and CM860 with the 25v 2200uF capacitors. I figured I could replace the CM860 for a 35v part if it worked.

The Board still requires heating around the area of the capacitors to start.

Does anyone know of any parts in that area of the board apart from capacitor that may allow the board to function if heated up?

There is a very faint high pitched noise that keeps cutting out(The inverter circuit?).
When the area near the capacitors is warmed the whine gets louder and cuts out less until the screen comes on.

Any help is appreciated. I'll try to get some photos uploaded soon.

Thanks

[Ecorecycler]

Re: Samsung LE32R88BD/ BN44-00155A

In the above post CM853 should be CM861.

Thanks

[budm]

Re: Samsung LE32R88BD/ BN44-00155A

Did you replace those small caps in the primary side? All the glues are removed?

[Agent24]

Re: Samsung LE32R88BD/ BN44-00155A

You could also check for cracked solder joints.

Maybe try heating things more selectively, see if you can narrow down the area that causes it to start working.

[budm]

Re: Samsung LE32R88BD/ BN44-00155A

BTW, pictures of YOUR board?
And see what bad glue can do to the board:
https://www.badcaps.net/forum/showthread.php?t=34692

[Ecorecycler]

Re: Samsung LE32R88BD/ BN44-00155A

Hi,
Thanks for your responses.

budm - I didn't replace the caps on the primary side as when I tried heating them from a cold board it didn't turn the set on. Do you think they may still be stopping the inverter from starting?
After seeing those pictures, I'll be making sure I remove all the old glue off the board.

Agent24 - I've tried to be selective using a piece of card but as I'm using a hair dryer the surrounding area still heats up a bit. It does appear to be in the area of the new caps. I thought I found the problem with a jumper that looked corroded, I desoldered it cleaned it and put it back in to no effect! I think maybe if I stick some aluminium foil on card it may help. If anyone has suggestions I'd be grateful.

I've taken some pictures but the lightings not good and I can't seem to upload. I'll try to do some more tomorrow in the daylight. I'll check back tomorrow.

Thanks for all your help.

[budm]

Re: Samsung LE32R88BD/ BN44-00155A

Common failure beside bad glue is the coupling/dc block cap ( the blue rectangular cap with 22nF 1250V printed on top next to the big transformer) is bad, the capacitance will go down, you need to remove it to test the capacitance.

[Ecorecycler]

Re: Samsung LE32R88BD/ BN44-00155A

Thanks, I'll take it out and check tomorrow. It's late here now and I've got an early start.

I was wondering if the caps I've soldered on to the board could be an issue. They are the same or higher voltage, capacitance and low ESR. I'm guessing they're just there for filtering the DC so should be OK?

[budm]

Re: Samsung LE32R88BD/ BN44-00155A

Higher Voltage is OK. Might as well recheck your soldering works.

[Ecorecycler]

Re: Samsung LE32R88BD/ BN44-00155A

Just a quick follow up....
The problem seems to be on the main board. Heat applied there while shielding the power board started the TV. My friend said he'd apply heat to get it started and use it like that until it failed. I tried to tell him that it would dry out the capacitors faster but he didn't seem to be concerned.

Thanks for all the help!

[DaTT]

Re: Samsung LE32R88BD/ BN44-00155A

Hello, I have a problem with the TV. Does not turn on, the red LED flashes. The time at which switch on extended to several hours (even through 12h). Thanks to this forum, I went into repairs. After replacing seven large capacitors TV is turned on after about 17 minutes. By this time, the voltage varies from 2.5 to 24,6V measured at DZM854. and further 0.1 to 5,3V measured at DZM853. After about 17 minutes, the TV turns on but do not keep a few seconds after it turns over and goes. I also swapped CY803S, RM801, CM810, CY804S, RB801, RB806 (they were hard sticky brown gum) and six small capacitors (CM806 CM807 ...). Does anyone have an idea? Thank you for the advice. DaTT.

[DaTT]

Re: Samsung LE32R88BD/ BN44-00155A

Today I measured the voltage on the rectifier(BD801S). When I connect only lead AC230V, I can measure on it a constant DC327V. If I connect the other cables and I turn on the TV, the voltage start pulsate from 225 to 327V. Can anyone advise what to focus on? Thank you for the advice. DaTT.

[budm]

Re: Samsung LE32R88BD/ BN44-00155A

The PFC Voltage booster is not working, the DCV on the main filter cap should be >360vdc when power switch is activated. Did you check the capaictance and the ESR of the main filter cap yet?

[DaTT]

Re: Samsung LE32R88BD/ BN44-00155A

The PFC Voltage booster is not working, the DCV on the main filter cap should be >360vdc when power switch is activated. Did you check the capaictance and the ESR of the main filter cap yet?

I took CP803, so I looked at him. Something flew in it. As if he was inside another slightly smaller capacitor, so I changed it for sure. Voltage on it slowly rises up to 330VDC and the TV is turned on. (after about 17 minutes) So it's the same. Voltage on it by the label on the PCB should be 385V. Something prevents him ascend to this voltage. Where is the fault? Thank you for your time. DaTT.