Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

[newbie1]

Hey guys,

After a few success in LCD MONITOR repairs, I decided to go into PAID ‘uncharted territory'.
So here goes…

Model : Samsung la32s81b.

Fault : Plugged. Pressed the Power switch on the TV. Power LED is red. Blinks 4 times. Then goes to STEADY red. No image. Backlight is OFF. No sound can be heard.

What I did : I opened the back cover and zoom-in on the Power board. I saw a SINGLE bloated capacitor (2200uF 10V) & some burn mark on the top of the board near ICB801S (A6159)…THAT'S GREAT!.. I tought. The bloated caps could be the ONLY problem. I happily ordered ALL the electrolyte capacitors (Panasonic FM/FC) on the Power board as the usual practice that I perform on my monitor repairs. Parts came, replaced them. I confidently cover the back again & plugged the Power cord. Guess what!.. STILL THE SAME FAILURE!..

I have downloaded the service manual from elektrotanya.com but could not see the error code for “Power LED Blinking 4 times”. Or maybe I do not know how to interpret it.

So now, I need to get the back cover off again to troubleshoot/measure the respective voltages/follow the trouble shooting procedure. But before I do that, I do hope to get some inputs from the knowledgeable guys here on what to lookout for. Do you think I need to replace ICB801S (A6159) too?
Or does anybody else have ever encountered the same problem? I will try to measure the VCC on the IC anyway.

I will update again once the voltage readings are done. Pictures attached (before recapped) for your viewing pleasure.

[Dgtech]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Did you replace all of the caps or just the bloated ones? If not, then do so. I have seen that whenever some bloat, there is one or two ready to do the same. They change value in capacitance which can be checked with a cap meter.

[hoadle]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Here the service manual

go section 4 Troubleshooting
Check all pins output at CNM801 (make sure pin 3 had Volt STBY(5.2V)) at section 8 Wiring Diagram page 202

[newbie1]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

@Dgtech - yup, i have changed all the capacitors on the Power board

@hoadle - thanks for the link. Here is what i have measured

1) CNM801 (that goes to the Main Assy) (all measurement taken with respect to Gnd screw)
* (Pin 1) Power-On/Off = 3.4V
* (Pin 3) STBY = 5.2V
* (Pin 13) 5.3V = 1.0V
* (Pin 19) 13V = 0.25V

2) CNM802 (that goes to the Inverter Assy) (all measurement taken with respect to Gnd screw)
* (Pin 1) 24V = 0.55V
* (Pin 12) B/L = 1.0V..

3) ICB801S (A6159)
* (Pin 2-3) VCC = 22V (Steady) (MAX is 19V?)..
* (Pin 4-3) Threshold Voltage = 1.14V

So from my understanding (correct me please..), the Power board is the problem but am i correct to only suspect that the ICB801S (A6159) is faulty?. Or is there somewhere else that i should look?
Hope somebody can confirm this..

p/s i have now removed the Power board from the TV so if any voltage measurement must be taken i have to open the back cover TV,, again..

[Dgtech]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

There is a square rectangular red fuse in the middle of the board. Was this checked as well? I dont know what it's job function is but it looks like it's separating one side from the other. After that, I'd check all the diodes. Make sure they are not reading zero ohms both directions. Then I'd look at the PWM chip. I havent located it on the board but I'd assum its the 16 pin IC chip.

[hoadle]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

If you removed the Power board from the TV & measurement volt from CNM801
* (Pin 1) Power-On/Off = 3.4V
* (Pin 3) STBY = 5.2V
* (Pin 7 & 8) = 12V for sound
* (Pin 13 to 16) = 5.3V
* (Pin 19 & 20 & 22) = 13V
If yes you mainboard is bad follow to charpter 9 Diagram
if not you power board is bad follow to charpter 9 Diagram
But make sure check square rectangular red fuse in the middle of the board from Dgtech (maybe that fuse is blowed)

[newbie1]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Hey guys, thanks again for all the inputs.

I believe I MIGHT have found the faulty component. ..

While measuring for shorts on the diodes as suggested by Dgtech, I happen to measure very abnormal (more than 600kohms) on resistor RM801 (to the left of the Big cap). Colors marked on the resistor are Red-Red-Silver-Gold so it should be 0.22ohms 5%, isn't it?
But i need advise on the wattage of this resistor (1W, 2W, 3W)?. Anybody knows?. Also, do you need to replace it with the exact type (metal oxide film, carbon, wirewound, etc)? or just a normal one would do?

For the record, the rectangle red fuse is measure ok (i.e 0.03ohms)

[PlainBill]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Hey guys, thanks again for all the inputs.

I believe I MIGHT have found the faulty component. ..

While measuring for shorts on the diodes as suggested by Dgtech, I happen to measure very abnormal (more than 600kohms) on resistor RM801 (to the left of the Big cap). Colors marked on the resistor are Red-Red-Silver-Gold so it should be 0.22ohms 5%, isn't it?
But i need advise on the wattage of this resistor (1W, 2W, 3W)?. Anybody knows?. Also, do you need to replace it with the exact type (metal oxide film, carbon, wirewound, etc)? or just a normal one would do?

For the record, the rectangle red fuse is measure ok (i.e 0.03ohms)

Correct, red, red, silver, gold is a .22 ohm 5% resistor, typically used to sense current. As for the wattage, I would suggest going to Digikey and searching for a .22 ohm, 5% metal film or metal oxide film resistor, then start comparing dimensions to the various wattages. As a wild guess, I'd say 1 or 2 watt.

PlainBill

[newbie1]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

.. SUCCESS!!

The faulty component is indeed the resistor RM801 (to the left of the Big cap). The guy at the local store confirmed that it is likely a 1W resistor but they ran out of it. So i bought a 2W 0.22ohms resistor, replaced it & IT FIRED UP!!..

So the family's first CRT TV, which is 8 years old by the way, is going up to the recycling fella's big truck, making its way to another third world country. .. thanks again guys..

May i add that there's aint no stopping this repair "addiction".
I am opening another thread that will need your expertise. Stay Tuned.

ADDITION : The 4 blinks then steady Red Power LED is NOT an error code. It did the same thing every time i turned it on. So my guess is, it is a normal start-up procedure.

[spintop]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

.. SUCCESS!!

The faulty component is indeed the resistor RM801 (to the left of the Big cap). The guy at the local store confirmed that it is likely a 1W resistor but they ran out of it. So i bought a 2W 0.22ohms resistor, replaced it & IT FIRED UP!!..

So the family's first CRT TV, which is 8 years old by the way, is going up to the recycling fella's big truck, making its way to another third world country. .. thanks again guys..

May i add that there's aint no stopping this repair "addiction".
I am opening another thread that will need your expertise. Stay Tuned.

ADDITION : The 4 blinks then steady Red Power LED is NOT an error code. It did the same thing every time i turned it on. So my guess is, it is a normal start-up procedure.

I have the same 32" LCD TV LA32S81B.
Initial problem cannot power up, I replaced all caps on the psu board and it worked (4 blinks on LED the image will display) successfully since last week.

Last 2 days, notice a problem - after power ON with 4 blinks LED (this is normal operation), the TV takes a while (20 sec) to have image display, and everything is normal.

Today, it has stop displaying the image, complete blank, but there is normal TV sound. I leave the tv with main power off for 30 mins, and turn on, i can get image after about 20 secs. Stranger intermittent problem

Hopefully someone with similar issues can advice.
Will post some pictures later.

[PlainBill]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

I have the same 32" LCD TV LA32S81B.
Initial problem cannot power up, I replaced all caps on the psu board and it worked (4 blinks on LED the image will display) successfully since last week.

Last 2 days, notice a problem - after power ON with 4 blinks LED (this is normal operation), the TV takes a while (20 sec) to have image display, and everything is normal.

Today, it has stop displaying the image, complete blank, but there is normal TV sound. I leave the tv with main power off for 30 mins, and turn on, i can get image after about 20 secs. Stranger intermittent problem

Hopefully someone with similar issues can advice.
Will post some pictures later.

First obvious question: Did you replace the electrolytic caps on the inverter?

Second obvious question: What caps (brand and series) did you use on the power supply?

PlainBill

[cadillacman]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

.. SUCCESS!!

The faulty component is indeed the resistor RM801 (to the left of the Big cap). The guy at the local store confirmed that it is likely a 1W resistor but they ran out of it. So i bought a 2W 0.22ohms resistor, replaced it & IT FIRED UP!!..

So the family's first CRT TV, which is 8 years old by the way, is going up to the recycling fella's big truck, making its way to another third world country. .. thanks again guys..

May i add that there's aint no stopping this repair "addiction".
I am opening another thread that will need your expertise. Stay Tuned.

ADDITION : The 4 blinks then steady Red Power LED is NOT an error code. It did the same thing every time i turned it on. So my guess is, it is a normal start-up procedure.

SWEET!!!!! Good find and fix!!!

[spintop]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

First obvious question: Did you replace the electrolytic caps on the inverter?

Second obvious question: What caps (brand and series) did you use on the power supply?

PlainBill

Hi Bill
I have not replaced any caps on the inverter board. Initially i thought changing the caps on the psu fix the problem, until this intermittent issue happened

I have ordered caps (Panasonic FM/FC) online last week, but it will take a while to ship to Asia. So all caps that i replaced are generic, hopefully once replace them with Panasonic will solved the issue.

Further investigation today:
Whether blank screen or normal image screen, all the signal on the connector CNM802 coming from the PSU are similar. There is stable
- 24V (Pin1-5),
- Gnd (Pin6-10),
- 1.8v (Pin12, BL ON/OFF),
- 0.8V (Pin13, Analog Dimming),
- 4.2V (Pin14, PWM Dimming)
I can conclude that PSU has no issue.

The inverter board has these major parts
- OZ964GN (Blank screen ENA-0v; VDD-0v ; Normal image: ENA- 4.6V, VDD-5.1v)
- BA10324AF
- 4614
- 4018L (transformer) (the secondary resistance 2.17K on all, except 1 is at 2.07K)

Please advice if this transformer could be causing the slow turn ON of the backlight, and eventually blank screen after i manually switching it on/off a few times. But after it cools down for 30 min it work OK.
My next step is to change the 4x270uf 35V caps on the inverter.

Can't find schematic for the inverter board (CMO I315b1-16a), anyone have it ?

[PlainBill]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Hi Bill
I have not replaced any caps on the inverter board. Initially i thought changing the caps on the psu fix the problem, until this intermittent issue happened

I have ordered caps (Panasonic FM/FC) online last week, but it will take a while to ship to Asia. So all caps that i replaced are generic, hopefully once replace them with Panasonic will solved the issue.

Further investigation today:
Whether blank screen or normal image screen, all the signal on the connector CNM802 coming from the PSU are similar. There is stable
- 24V (Pin1-5),
- Gnd (Pin6-10),
- 1.8v (Pin12, BL ON/OFF),
- 0.8V (Pin13, Analog Dimming),
- 4.2V (Pin14, PWM Dimming)
I can conclude that PSU has no issue.

The inverter board has these major parts
- OZ964GN (Blank screen ENA-0v; VDD-0v ; Normal image: ENA- 4.6V, VDD-5.1v)
- BA10324AF
- 4614
- 4018L (transformer) (the secondary resistance 2.17K on all, except 1 is at 2.07K)

Please advice if this transformer could be causing the slow turn ON of the backlight, and eventually blank screen after i manually switching it on/off a few times. But after it cools down for 30 min it work OK.
My next step is to change the 4x270uf 35V caps on the inverter.

Can't find schematic for the inverter board (CMO I315b1-16a), anyone have it ?

We've had a few cases where someone recapped a monitor using general purpose (NOT low ESR) caps and the monitor displayed 'two seconds to black'. Replacing the GP caps with low ESR solved the problem. Your results may vary.

PlainBill

[retiredcaps]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

- 4018L (transformer) (the secondary resistance 2.17K on all, except 1 is at 2.07K)

The 2.07K reading is a bit outside of PlainBill's 3% threshold. See

https://www.badcaps.net/forum/showpo...7&postcount=18

I'll leave it to him to comment.

I did notice that lcdparts.net lists the secondary resistance as 1.10K at

http://lcdparts.net/TransformerDetai...ProductID=3497

[PlainBill]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Whoops, I wasn't paying attention earlier. I wouldn't replace a transformer yet; I'd wait until proper caps were installed. However, these reading are interesting;

The inverter board has these major parts
- OZ964GN (Blank screen ENA-0v; VDD-0v ; Normal image: ENA- 4.6V, VDD-5.1v)
- BA10324AF

I'd have to look at the circuitry, but Vdd dropping to 0 volts is NOT normal. I'd trace the source of ENA and Vdd. BL_ON seems a little low compared to other inverters.

PlainBill

[spintop]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

The 2.07K reading is a bit outside of PlainBill's 3% threshold. See

https://www.badcaps.net/forum/showpo...7&postcount=18

I'll leave it to him to comment.

I did notice that lcdparts.net lists the secondary resistance as 1.10K at

http://lcdparts.net/TransformerDetai...ProductID=3497

Thanks for the link. I found I measured wrong pins.
Here are the measurement of secondary disconnected from CCFL.

T1: 1.065k, 1.066K
T2: 1.045k, 1.047k <==== outside of range ?
T3: 1.073k, 1.075k
T4: 1.067k, 1.071k
T5: 1.070k, 1.073k
T6: 1.072k, 1.074k
T7: 1.066k, 1.066k
T8: 1.058k, 1.059k

[spintop]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Whoops, I wasn't paying attention earlier. I wouldn't replace a transformer yet; I'd wait until proper caps were installed. However, these reading are interesting;

I'd have to look at the circuitry, but Vdd dropping to 0 volts is NOT normal. I'd trace the source of ENA and Vdd. BL_ON seems a little low compared to other inverters.

PlainBill

Hi Bill
Setting DMM to lower range, I got 0.15v instead of 0 for both ENA & BL_ON.

[PlainBill]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

Hi Bill
Setting DMM to lower range, I got 0.15v instead of 0 for both ENA & BL_ON.

That would indicate it is a problem with the main board. BL_ON is usually about 3 volts when the backlights are on.

PlainBill

[retiredcaps]

Re: Samsung 32" TV. No image, backlight or Sound. Power LED Blinks 4 times.

T1: 1.065k, 1.066K
T2: 1.045k, 1.047k <==== outside of range ?
T3: 1.073k, 1.075k
T4: 1.067k, 1.071k
T5: 1.070k, 1.073k
T6: 1.072k, 1.074k
T7: 1.066k, 1.066k
T8: 1.058k, 1.059k

1.10k x 0.97 = 1.067
1.10k x 1.03 = 1.133

So the range would be 1.067 to 1.133. That would suggest T1, T2, T7, and T8 are out of tolerance IF the 1.10K reference is correct from lcdparts.net.

There will also be some variation depending on the accuracy of your multimeter.

If we IGNORE the lcdparts.net 1.10k and just use the readings that you have, then

1.075k x 0.97 = 1.043.

That would imply T2 is just within the 3% threshold.