Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Hi again.
I've received my bridge rectifier and replaced it.
I have also ordered another power board (used).
With this replacement board, the TV works. So I can compare components between the two board if needed.
I've replaced the bridge rectifier on my board and re-soldered the MOSFET.
Now, fuse isn't blowing. Great !
But, TV stay in standby mode. I can't power it on.
Red led is blinking... pressing power button does noth...
BmD_Online
Member
Last Activity: 04-28-2020, 12:22 AM
Joined: 01-05-2020
Location: Sud
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Finally, I have unsoldered bridge rectifier.
And... all diodes are blown.
about 6 Ohms between + and -
about 1 Ohm between ~ and ~
In diode mode, all pins beeps between each other.
I have ordered another brider rectifier (same ref) from AliExpress.
Chinese new year, dispatch time... I should receive it within 37 days !
In the meantime, I have received new MOSFET. I have compared values and confirm previous one isn't blown.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
RM801 ? sure ?
when lifted :
5.2 Ohms between + and -
0.7 Ohms between ~ and ~ (internal multimeter resistance is about 0.6 0.7 too)....Last edited by BmD_Online; 01-27-2020, 02:30 PM.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
I have unsoldered the MOSFET.
PFC MOSFET : different values according to multimeter position :
103.4 K (multimeter set to 200K)
15.54K (multimeter set to 20K)
bridge rectifier + - : 5.2 Ohms
bridge rectifier ~ ~ : shorted
RP819 : 0.8 Ohms (meter probes resistance is about 0.7)
Looks like MOSFET isn't blown, but bridge rectifier is !
Do you know an equivalent of TS4B05G ? I have difficulties to find a...Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Yes it is. 6.3A.
I've ordered new MOSFET. I'll come back when I receive and replace it.
We'll made controls at this moment.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Yes, fuse blow directly when I bypass the lamp.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Without unsolder anything :
PFC MOSFET : 5.5 Ohms
bridge rectifier + - : 5.2 Ohms
bridge rectifier ~ ~ : shorted
RP819 : 0.8 Ohms (meter probes resistance is about 0.7)
I suppose I have to unsolder MOSFET, check it again and check bridge rectifier too ?
And, if I replace MOSFET, I have to replace ICP801S (tda4863-2) again ?
I have a second one, but I have to buy a new MOSFET and/or bridge rectifier if needed.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Here it is....Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
About dim bulb tester I mean when everything it right (after power supply repair), can I make TV power on and work correctly connected to dim bulb tester ?
Or I only can check for shorts, bu don't make it work fully.
I'm not sure my question is clear.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Does the TV have to switch on when dim bulb tester is used ?
Can I create a short circuit connecting inverter to wrong connector (S or A) ?
I have double/triple checked all replaced caps.
All solders joints seems to be correct.
I will verify diagram. Maybe I've made a short when soldering SMD circuit (near to pin 4), but I don't think so.
I will try to check all diodes too. Not checked yet.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
You're right. I think I've burned MOSFET again with this attempt !
Right now, I'm a little upset.
Same power supply board is sold 15€ on eBay (refurbished) !
I think I'll buy it, check if TV works, and compare the two boards.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Hi,
I have replaced the MOSFET and ICP801S.
I've build a Dim Bulb Tester (105W halogen bulb), and connected TV.
Once connected, TV seems to be in standby mode (red led on).
When I press start button, the bulb gets dim, but nothing happens to TV.
I've tried without dim bulb tester, and... fuse blows, and... circuit breaker trips (we say like that in english ?) !
I have spend to many money according to TV age, so I'm giving up !
...Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Soldered, I read 0.8 Ohms.
Probing my meter itselt, I have about 0.6-0.7 Ohms.
I can't be more precise.
Edit : Soldered, not Unsoldered !Last edited by BmD_Online; 01-21-2020, 12:17 AM.Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Which component is "PFC Controller IC" ?
Please don't tell me it's ICP801S (tda4863-2) ! SMD component, I hate them !Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Resistance is the same between + and -, and between ~and ~ : about 77K.
I will change the MOSFET !Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Phew, I've removed it !
Using my multimeter or using an electronic tester (mtester) I read different values.
See attached pictures.
Using multimeter, I read 0.7 Ohm.
Using mtester, I read different values around 10-15K, sometimes around 5K....Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Yes, got it : W20NM60 mosfet.
I read 0.6 ohm between S and DLeave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Hi,
between + and -, I read 1 ohm
between ~ and ~, I read 5.4 ohms
QP801S ? You're talking about F9222L ICM801S ?
I read different values according to my multimeter :
in diode mode : 480
in resistance mode, weirded values, changing during readingLeave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
Damn. Really hard to unscrew and unsolder !...Leave a comment:
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Re: Samsung LNS3251DA won't power on, no sound, no standby light-power board problem
You're right. ts4b05g shorts between each pins (kept soldered).
I don't know dim bulb tester. I will have a look.
My parents (it's not my TV) found a new Samsung for less than 180€. They bought it !
I will try to repair this one, but just for fun.
At some point, the repair is no longer going to be profitable !
I will try to change bridge rectifier.
Wait and see.Leave a comment:
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