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Old 04-08-2021, 03:49 AM   #1
Ukdigger
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Default Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

TV works normally for about 10 minutes then the picture freezes and then the TV goes into a restarting loop. All the voltages seem ok and all the caps on the power board look ok and test ok with ESR meter. Inverter board to power board lead has burn marks at the power board end as shown in pictures. No signs of burning on the inverter board and caps test ok. Not sure if this is a problem but Diode DM804 (schematic D2) on the power board reads as shorted in circuit but disconnecting one leg it reads normal. Disconnecting the inverter board makes the TV stay on permanently with all voltages testing as in diagram. Any help would be greatly appreciated.

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Old 04-08-2021, 05:11 AM   #2
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

On the surface those reading look ok except you have 24V on CNM803 pin 10 which I suspect is in error.

You could try a can of freezer spray ( or inverted can of air duster spray) to cool down the EEPROM or BGA IC's on the mainboard and see if that helps.

DM804 is in parallel with a 0.2 ohm resistor so would read short when still connected to the board.
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Old 04-08-2021, 12:55 PM   #3
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

Yes I made a mistake on the voltages it should have been a ground on CNM803 pin 10.
There's a big heat shield covering the chips so I put a computer case fan on top and powered it up and it doesn't shut down anymore. So something is getting too hot.
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Old 01-29-2022, 08:52 AM   #4
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

Found a main board on ebay for 23 with all the numbers matching the old board. Everything seems to be ok now with the bonus of having a UK tuner, the old one was locked on Hong Kong region with no other options so the clock was always a few hours out on the guide which was very annoying.
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Old 01-29-2022, 10:04 AM   #5
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

Hope you took care of the connector problem.
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Old 05-21-2022, 02:14 AM   #6
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

I made a mistake, the main board on ebay for 23 was for a 40 inch Tv in one of my other posts.
I removed the big heat shield covering the chips and noticed heat colour distortion and brown circular marks where the two capacitors had been touching it. I put a PC heat sink on the graphics chip and the TV worked with no problems. I drilled extra holes it the heat shield cover so that the capacitors didn't touch it anymore and the TV has been working with no problems now for 2 weeks.
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Old 05-21-2022, 05:29 AM   #7
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

Nice fix.
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Old 05-21-2022, 12:34 PM   #8
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Default Re: Samsung LE37R88BDX/XEU BN44-00157A Turns off after 10 minutes

Quote:
Originally Posted by Ukdigger View Post
I made a mistake, the main board on ebay for 23 was for a 40 inch Tv in one of my other posts.
I removed the big heat shield covering the chips and noticed heat colour distortion and brown circular marks where the two capacitors had been touching it. I put a PC heat sink on the graphics chip and the TV worked with no problems. I drilled extra holes it the heat shield cover so that the capacitors didn't touch it anymore and the TV has been working with no problems now for 2 weeks.
Just go into the service menu and change the screen details then the board will work with your TV. Compare the details with your existing main board (take pictures is easiest) and modify the 40inch one to your existing faulty one. Press info menu mute and power button on remote control quickly to access service menu. Turn power to standby to implement changes after you have modified settings and exit the service menu. Don't change any settings besides screen types.
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