kavleas
Member
Last Activity: 05-04-2025, 06:59 AM
Joined: 03-05-2023
Location: Athina
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Thanks for clarifying! -
So I'd better look for a replacement board... Standby voltage is working (3.3V) but when powered on the led blinks 3 times and that's all. Is the PFC necessary for the power supply to work?Leave a comment:
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Lovely, thanks both for your help! Looking more closely I see that Q601 is also shot. If I can tell right it's a 6N50S? And all this circuitry is part of PFC?Leave a comment:
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2722.171.00749.V30103Leave a comment:
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Hi, realize it's an old topic but i wonder if the u601 on my philips 32pfl5604h/12 pcb is the same! I cannot tell any detail as it is blown. The board is a PLHL-T808A (LIPS32 FHD). Should I open a new topic?Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Too bad I dumped the one I had, it might be of assistance with the voltages!Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Power supply is ok, I guess there was low voltage when not connected to the rest pcbs. Now (connected) it measures 5v and 12.8v. Anyway I've had it with this set, I think it's time to get rid of it...Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
I removed the grey ribbon (touch pcb) from the small pcb and the short is gone. Powering on, the cap voltage is 5 volts, ir still works but once again no image or sound. Going to remove the diode and see...Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
There is the culprit for the high current on the 5v stand by voltage! The diode and the cap are shorted. Trying to find a way to turn on the set without the panel (led,touch,infrared) connector.
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Re: Samsung le40a656a1f reaaaaaly slow poer up
I thought to check if something is shorted on the mb and affects the psu. I see 4 431s on power supply, I checked the feedback one. Will check the rest and try to find replacements.Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Wow THAT was fast, thanks!Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
I get a bizarre reading when connecting ammeter between psu and mb on the 5v stand by rail. It indicates 0.5A. This doesn't seem normal (tv is turned off). Is there a schematic of the mb (BN41-00974B)?Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Unfortunately I can't seem to find a 431 to replace the existing one but it's a zener diode and it measures ok. Voltage accross led part of optocoupler PCM801 is 1v....Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Removed 431 (ICM803) and it measures ok. What I still don't understand is what happened when heating the electrolytics and the voltage rose!...Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Standby:315V, Power on:380V...Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Funny, voltage reached 11.5 volts and when connected to load (car bulb 60w) it dropped to 5 volts and the backlighting was flashing on and off!Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Lights right up, voltage still 9.6.Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
No, the backlight board is unplugged too. When it was plugged, it would light after 10-15 seconds. I could short pins 1 with 5 on the 5pin connector and light it in full.Last edited by kavleas; 04-04-2023, 05:41 AM.Leave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Already done that, power supply is disconnected from the other pcbs and ps on is connected to 5v. 13v pin reads only 9.6vLeave a comment:
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Re: Samsung le40a656a1f reaaaaaly slow poer up
Nothing on screen, although the backlighting is lit dimmed. There must be something wrong with the 13v rail as when load is connected it drops to 4-5 volts and slowly rising to 9-11 volts. The 5v seems rock solid. BTW this is the psu diagram....Leave a comment:
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