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Old 10-08-2021, 06:42 AM   #1
bstewara
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Default Samsung un49mu7000f dead no power

Hi.
I知 working on a Samsung UN49MU7000F that has no standby LED indicator.
No POWER
The power supply board is part number BN44-00876A
The main board number is BN94-12399A
I am stuck.
I have replaced both pwr supply and main board with no changes.
Here are some of the readings from my multi meter on various locations on my power supply

MAIN BOARD UNPLUGGED. BACK LIGHTS ON PLUG CNL802 85 volts
Backlights are all illuminated and in operating range.

MB PLUG CNM803. - UNPLUGGED

PIN 1 FAN COUNT - Open
PIN 2 ANA DIM - Open
PIN 3 A13V. - 12.89
PIN 4 OD ON/OFF - 2.163
PIN 5 A13V. - 12.89
PIN 6 PWM BLU - 2.106
PIN 7 A13V - 12.89
PIN 8 PWR ON - 1.665
PIN 9 A13V - 12.89
PIN 10 GND- GND
PIN 11 GND -GND
PIN 12 GND-GND
STB VOLTAGE TEST POINT ON BOARD 12.89. (Should read 7.5 and 11.8)

With MB PLUGGED IN. NO BACKLIGHTS.

MB PLUGGED IN CNM803 READINGS

Pin 1 FAN COUNT open
Pin 2 ANS DIM open
Pin 3 A13V 9.03
Pin 4 OD ON/OFF open
Pin 5 A13V 9.03
Pin 6 PWM BLU 34 ohms
Pin 7 A13V 9.03
Pin 8 PWR ON open
Pin 9 A13V 9.03
Pin 10 GND. gnd
Pin 11 GND gnd
Pin 12 GND gnd
STB VOLTAGE AT TEST POINT 9.03

I知 just not sure of what voltages should be reading at CNM803.
Any help would be appreciated!
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Old 10-11-2021, 07:31 PM   #2
Storyteller12
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Default Re: Samsung un49mu7000f dead no power

It’s the main board. If backlights work with mb disconnected that mean power board is good. You must have got a defective mainboard. Even if the panel was bad the standby light would be on when the tv is off.
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Old 10-11-2021, 07:33 PM   #3
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Default Re: Samsung un49mu7000f dead no power

I actually just fixed one with similar issue. It’s the eeprom on the main board causing the problem. See if you can find a replacement eeprom on shopjimmy or eBay
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Old 10-12-2021, 05:55 PM   #4
bstewara
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Default Re: Samsung un49mu7000f dead no power

Hi,
I have replaced the main board with 2 different replacement boards from TV PARTS TODAY and also replaced the power supply board once with no change.
(Am I getting defective boards from TVPARTS TODAY? They’re supposed to be fully tested before shipping)

I’m a little curious to why I’m not getting the 3 VDC standby voltage.
I’m just not sure what voltages I’m supposed to be getting on CNM 803 as they aren’t marked on the PS board.
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Old 10-12-2021, 06:09 PM   #5
R_J
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Default Re: Samsung un49mu7000f dead no power

Quote:
Originally Posted by bstewara View Post
I’m a little curious to why I’m not getting the 3 VDC standby voltage.
I’m just not sure what voltages I’m supposed to be getting on CNM 803 as they aren’t marked on the PS board.
The voltages and pin numbers for CNM803 are clearly marked on the BN44-00876A power supply board.
There is no 3.3 volt standby supplied by this power supply, only A13v The main board supplies all the other lower voltages.
With power removed, disconnect the two cables going to the panel, plug in tv and see if it will turn on (there will be no picture)

Last edited by R_J; 10-12-2021 at 06:15 PM..
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Old 10-12-2021, 08:08 PM   #6
Storyteller12
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Default Re: Samsung un49mu7000f dead no power

Unfortunately tvpartstoday doesn’t really know which boards are good. I’ve had several main boards from them that are defective.

Now they don’t even ask me to return them for the refund.
There prices are good and so is there return policy. So I still use them as a last resort sometimes.

I’m almost positive it’s the main board. Unfortunately they are getting harder to find for the mu series TVs.
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Old 10-16-2021, 04:49 AM   #7
bstewara
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Default Re: Samsung un49mu7000f dead no power

Thanks Much
I will try and find another MB .
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Old 10-16-2021, 05:31 AM   #8
lotas
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Default Re: Samsung un49mu7000f dead no power

Quote:
Originally Posted by bstewara View Post
Thanks Much
I will try and find another MB .
If you have a programmer, then read the dump from the spi flash ic1604 W25Q40CL and put it here, I will fix it for you and you will write it back and your samsung will work.
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Old 10-26-2021, 07:09 AM   #9
bstewara
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Default Re: Samsung un49mu7000f dead no power

Hi,
I知 not seeing ic1604
However I found ic1603 (25q80dvsig). (1733)
Could this be the correct ic for this model?

Thanks again
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Old 10-26-2021, 08:49 AM   #10
lotas
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Default Re: Samsung un49mu7000f dead no power

Quote:
Originally Posted by bstewara View Post
Hi,
I知 not seeing ic1604
However I found ic1603 (25q80dvsig). (1733)
Could this be the correct ic for this model?

Thanks again
Do you have a mainboard BN41-02568B?
Attached Images
File Type: jpg main-bn41-02568b-photo-2c63.jpg (255.5 KB, 4 views)
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Old 10-26-2021, 08:57 AM   #11
lotas
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Default Re: Samsung un49mu7000f dead no power

BN41-02568B

IC901 SDP1601 ver.05 S5WWPT H1730
IC701 KLM461FEPD
IC1001,1101 K4F8E30 4HBMGCH
IC1604 25Q40CLSIP
IC1603_UT_KTN 25Q80DVSIG
IC201 AWR7GB
IC303 54627 TI 76A P42CG3
IC203,IC207 T282 2897
IC400_UT VPM1R0A 728205A
IC209,IC2301 LR1801G
IC802 10358 7271
IC801 24512FD
IC204 T21T G942
IC401_PFFU VLS1R0A 726432A
IC302 T297 5334
IC1901_CI 74LCX244 OH301
IC2302_DS 65235 TI 781 AQ9G
IC301,IC206,IC202,IC205 3201
IC1402,IC1401 18PF


Remove the radiator.
Attached Images
File Type: png BN41-02568B.PNG (714.0 KB, 10 views)

Last edited by lotas; 10-26-2021 at 09:06 AM..
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Old 10-26-2021, 10:15 AM   #12
bstewara
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Default Re: Samsung un49mu7000f dead no power

No,
I’m sorry my main board is BN94-12399A

Thanks
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Old 10-26-2021, 10:21 AM   #13
bstewara
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Default Re: Samsung un49mu7000f dead no power

Hi,

I did find it!
Thanks for the photo.

Do you know if this ic can be purchased pre flashed and ready to install?
I don’t have a programmer

Thank you for all of your help
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Old 10-26-2021, 10:37 AM   #14
lotas
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Default Re: Samsung un49mu7000f dead no power

Quote:
Originally Posted by bstewara View Post
No,
I知 sorry my main board is BN94-12399A

Thanks
Why not?
Attached Images
File Type: jpg 12399A.jpg (187.5 KB, 5 views)
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Old 10-26-2021, 10:47 AM   #15
lotas
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Default Re: Samsung un49mu7000f dead no power

I don't know where to buy this microcircuit, buy the simplest CH341 programmer.
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Old 10-26-2021, 12:10 PM   #16
bstewara
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Default Re: Samsung un49mu7000f dead no power

Hi lotus
I just want to thank you for your assistance!
You致e been a great help!

Thank You
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Old 10-26-2021, 12:26 PM   #17
bstewara
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Default Re: Samsung un49mu7000f dead no power

Hi lotus,
I ordered a programmer I will send you the dump from the spi flash next week sometime.
Thanks again
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Old Yesterday, 04:40 PM   #18
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Default Re: Samsung un49mu7000f dead no power

@bstewara, Did you solve this problem?
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Old Yesterday, 06:50 PM   #19
bstewara
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Default Re: Samsung un49mu7000f dead no power

Sorry
No I did not.
I致e had a difficult time finding software for the ch341 programmer.
I think I知 going to try and find a pre programmed chip to install or purchase another main board.
Not sure I have the expertise to repair flashing the chip.

Regards
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Old Yesterday, 07:31 PM   #20
hasitha prasad
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Default Re: Samsung un49mu7000f dead no power

As far as I know, Asprogrammer is the best software for CH341A
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