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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Samsung UN65H7150 - only backlight, no picture

 

 


ghiros
New User

Sep 9, 2018, 8:24 PM

Post #1 of 15 (259 views)
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Samsung UN65H7150 - only backlight, no picture Can't Post

Hello,

I'm trying to get some informed guesses about what could be wrong with my TV. When I plug it in, the backlight comes on immediately, but there is no picture, no menu. It doesn't respond to remote input or using the physical button (i.e. I cannot even turn it off without unplugging it).
Can't tell whether there is sound, because I can't be sure which input it might be set to.

I'd rather not replace components willy nilly, because they seem to be quite pricey for this model.

Thank you for any input you might have!



jts1957
Veteran


Sep 10, 2018, 2:40 PM

Post #2 of 15 (244 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Presuming all power supply CNM803 voltages are present, Main Board is likely.


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Location: Far, Far Away


ghiros
New User

Sep 13, 2018, 6:00 PM

Post #3 of 15 (214 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

I'd like to check, but cannot find anywhere what voltages to expect.
Also, can somebody tell me why there are two stickers with different numbers on the mainboard?

https://ibb.co/hkOLpp

And some merchants specify part numbers and board numbers. How do they relate?

https://gopartserv.com/...ariant=8008787132467

Thank you!


jts1957
Veteran


Sep 13, 2018, 6:57 PM

Post #4 of 15 (212 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

power supply CNM803 voltages
ARE labeled on the POWER board. You are referencing the Main board.

https://www.shopjimmy.com/samsung/un65h7150afxza


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Location: Far, Far Away


ghiros
New User

Sep 14, 2018, 3:26 AM

Post #5 of 15 (210 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Sorry, I'm still pretty new to this. I was aware I was referencing the main board, though. My question is still why there are different numbers on the stickers and what they mean in terms of compatibility.

Thanks for your help!


jts1957
Veteran


Sep 14, 2018, 4:11 AM

Post #6 of 15 (208 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

The others may mean something to the manufacturer (date codes, supplier, board serial #, etc.), but the important one in obtaining a replacement will be the manufacturer's part number on a sticker and possibly the version number on the model number tag on back of the set. If you have perused the various links in the shop jimmy link I previously gave you may have noticed the following:

Quote
PLEASE NOTE: You will receive either main board BN94-08192L or BN94-07345E. These two boards are interchangeable.

Strange that they don't show that in a "substitute parts" line in each boards' listing.


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Location: Far, Far Away


ghiros
New User

Sep 15, 2018, 2:38 AM

Post #7 of 15 (201 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Thank you, I did notice the numbers on Shop Jimmy, but when looking for them online I found several sites that claim other board numbers as interchangeable - actually these:

BN94-07345E
BN94-08192L
BN97-08117B
BN41-02157B
BN97-08922T

Also, I did check the CNM803 voltages as printed on the board. They all said 13V, and the meter showed 12.6V. Is that acceptable?


jts1957
Veteran


Sep 15, 2018, 3:42 AM

Post #8 of 15 (197 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

A 'Board Number' is NOT a 'Part' Number.
Valid board 'Part' Number(s) will always start in this instance with BN94-.

12.6V is close enough for b-plus.
CNM803 has two rows of 11 pins. 'Even' number pins are easily accessible from top of board. 'Odd' number pins are NOT easily accessible from top of board. The row of pins you didn't test have the control voltages, PS-ON and BLU-ON for example. While the power supply will turn on the backlights when either end of the cable from Main to Power Supply is unplugged, The Main board does NOT receive B-Plus, nor can it send any control voltages while cable is disconnected. With connectors plugged in you should be able to 'back-probe' the 'odd' pins.


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Location: Far, Far Away


ghiros
New User

Sep 17, 2018, 3:34 AM

Post #9 of 15 (181 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

So I checked the voltages with the TV plugged in. This is what I got:

PWM-DIM: all 3.21V
0D-ON: 1.3V
0D-LEVEL: 1.3V
PS-ON: 3.25V
BLU-ON: 5.05V
Vamp: all 12.78V

What's my next step?
Thank you for all your help!


jts1957
Veteran


Sep 17, 2018, 3:47 AM

Post #10 of 15 (179 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Do PS-ON & BLU-ON Toggle from low to hi with each press of the power button?


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Location: Far, Far Away


ghiros
New User

Sep 17, 2018, 3:51 AM

Post #11 of 15 (176 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

The power button doesn't seem to do anything. As soon as I plug it in, the backlight comes on.


jts1957
Veteran


Sep 17, 2018, 7:10 AM

Post #12 of 15 (172 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

So if they do not change, then Main board is likely.


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Location: Far, Far Away


ghiros
New User

Sep 17, 2018, 7:36 PM

Post #13 of 15 (166 views)
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Re: [jts1957] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

That thing is kinda hard to find and fairly pricey, but I'll give it a shot and report back. Thanks!


ghiros
New User

Sep 25, 2018, 7:13 PM

Post #14 of 15 (117 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Was supposed to get delivered today and I just got the message to "kindly allow an additional 24 - 48 hours for delivery" with the last tracking status being from 9/18.
Thanks, DHL. Mad


ghiros
New User

Oct 2, 2018, 5:34 PM

Post #15 of 15 (51 views)
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Re: [ghiros] Samsung UN65H7150 - only backlight, no picture [In reply to] Can't Post

Finally received the main board and had a chance to swap it.
TV is back alive and working great!

Thank you, jts1957!!

 
 
 


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