Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
QM951 and QM952...
realfastbug
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Last Activity: 01-29-2021, 10:21 AM
Joined: 08-09-2018
Location: DENVER
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
SEM3110A
[url]https://www.ebay.com/itm/254409159810[/url]Re: Samsung UN65JS9500 / BN44-00818A...09159810[/url]Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
FYI, to close this out. I replaced the primary controller chip and FETs as well as the secondary FETS and obviously the fuse. When it powered up it was squealing which I assumed was running in current limit. I unplugged the LED driver board and the squealing went away. I already had another LED driver board from when my brother was trying to fix this. I swapped the other driver board in and the squealing went away and has been running great. Unfortunately I am not sure which LED driver was the original so I am not sure what...Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
I haven't taken the time to figure out the whole pinnout but it looks like gate drive A goes to pin1 and gate drive B goes to pin4 ....Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
I haven't been able to figure out what manufacturer part number that is yet. I searched a lot of synchronous rectifier controller ICs but none seem to have that pinout. I also have looked at a bunch of other samsung power supply schematics and they don't use this same circuit.
Anyone have ideas on this part?...Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
Hi, are you asking what the manufacturer part number is?
does it have the same markings as CM901?...Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
I haven't verified the control IC yet other than I can say that the place that repaired the board did not replace it. The gate drive resistors were ok though. My brother said it worked for a few hours then the PS blew up again so it must have an issue beyond the fets that were replaced....Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
hopefully I can get back to this next week. I did confirm with my brother that he sent this out and the primary and secondary fets were replaced along with the fuse. He said is worked for a few hours then failed again, that's when he dropped it off at my house and said have fun. One thing I noticed is the pcb seems to be a little discolored on the secondary side area between the transformer and the fets like it got hot. maybe just the repair guy was over zealous.Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
That makes more sense as there is a cap going to pin4 and measured around 4v....Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
ok, I jumped the gun. The fuse is blown. I removed the primary side fets and they are shorted but the gate drive resistors and the fast-off gate drive res-diode groups look to be ok. The secondary fets also look ok. However, I realized this board has been sent in for repair already as all of these parts had already been changed before. I will see if I can find more into on who did the repair. The primary fets had been changed out with a slightly different part with lower gate charge but the specs seem similar enough I would...Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
looks like this could be the IC [url]https://cdn.badcaps-static.com/pdfs/edad988893d339cb75c0340fed53a49c.pdf[/url]Re: Samsung UN65JS9500 / BN44-00818A...a49c.pdf[/url]Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
its the IC in position ICM901. It is also used in ICM801. Have you been able to find the replacement IC for that controller?
RM911, 912 are the 100 ohm gate drive resistors that are probably damaged as they read about 1ohm in circuit. I haven't removed anything components yet.Leave a comment:
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Re: Samsung UN65JS9500 / BN44-00818A - no LED backlight
Hi, too bad this thread didn't get followed up till the solution was found. I recently was given this same model tv with what appears to be the same issue.
As Bud suggested I checked the gate drive resistors and they look to be blown. When I used to work on power supplies this usually meant the controller IC also is suspect. However, I cannot read the markings on this chip. it looks like it may say "3110" or maybe "8110"? Do these designs tend to use certain chips that might narrow this down?...Leave a comment:
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