Re: LG 42LW4500-LB Need help with repair of PSU
The incoming mains of 230v ac is rectified to produce DC and then that DC voltage is increased by the circuit to approximately 380 - 400V DC.
There is no point in changing anything until you find that it is faulty!!!
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Re: LG 42LW4500-LB Need help with repair of PSU
Okey but I dont understand why they put higher voltage capacitors than it came to board they are dimensed to 470v nothing in my country has 450v maximal range from plug is 380v i will wait 2 days until my school starts and i will ask my teacher for help to find the problem i returned the thermistors do you think it helps when i bought new capacitors and replace them ?Leave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
It's very likely the set has powered down because there is a fault, however that is what you are trying to find. Nothing is blowing up or burning.
You really need a meter that has a 600V DC range to test that the mains supply is being rectified and is reaching the higher voltage parts of the circuits. For example to find out if you have 400V on those capacitors.Leave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
Yes I can but before I will return the thermistors also must i plug the 230v in it ? i had the down model of board so i will check it but i think the leds work because my tv turn on for second and then turn of like she found short circuitLeave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
The attached picture looks like your power supply and if from an LG-47LW5700 model.
Can you check you have the voltages shown in the table.Attached FilesLeave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
Check the forum using the search feature on how to test Psu.Leave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
Okey so thermistors are good if they signal short ? I dont know what is main filter cap on this board but I think it is the gray one (photo in attach) also how can i find the voltage without put in in my 230v plug ? Iam noob in this
hte black thing under the gray capacitor is 230v plug
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Re: LG 42LW4500-LB Need help with repair of PSU
There are a number of fuses on the board which you have checked and were OK?
What dc voltages do you have across the 2 legs of each of the 3 long capacitors.Last edited by dick_barton; 11-19-2016, 09:46 AM.Leave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
They are probably OK. Measure their ohmic value.Leave a comment:
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Re: LG 42LW4500-LB Need help with repair of PSU
Thermistors should show short or low ohms, what voltage have you got on the main filter caps ?Leave a comment:
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LG 42LW4500-LB Need help with repair of PSU
Hi guys today my TV stops working (it woudnt turn on only led shine so the power goes into it) so i remove the back panel and unscrewed the PSU I checked the capacitors but all of them seems to bee good psychicaly I dont check their capacity if its good or not because no one of them is leaked after that i check whole board with my multimeter (PAN33D) and i found 2. suspicious components (it was thermistor) when i put + and - of my multimeter on it and multimeter was set to beep when he found short-circuit it beeps so I dissolder this 2 thermistors and do it again i again put + and - of my multimeter on their poles and it against beep so i think my TV wasnt start because this thermistors are in short-circuit (i read thermistor is for protecting whole board from short-circuit) So please can you help me ? I also need buy new but my local store doesnt have this one (I put photo in attach smaller one had DSC10D-9 printed on it and the bigger one had DSC-5D-15 120) if you dont understand me i will record a video on Youtube.Thanks for help
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I am new to electronics and I'm understanding most of what I'm reading but I have a mosfet on my board that I've identified as a P-channel Trench Mosfet. I haven't a clue how to test this and what I should expect to see with the multimeter probes. I am hoping someone with years more experience than myself can help me understand how to use a multimeter to read this. Please look at the drawing I have attached to this and can you try to explain to me what I should be doing with my multimeter in diode mode and what results I should expect from a good mosfet?...
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Machine: Autoclave.
Brand/Model: SANYO MLS-3780
Manual: (Sorry search option not working on this PDF)
Hello guys, this autoclave running with 2 thermistors already connected TH1 and TH3(on CN1,CN2 sockets). One for the water temperture and second one for chamber temperature. But there is another emtpy socket for optional third thermistor CN2 wich is for TH2 for object temperature. I wanna add the third thermistor TH2 to CN2 socket. But i can't figure what model/brand/value i need to use. In manual document, there is no info about TH1 and TH3 model number... -
I am having an issue with my wall oven temperature control is ~180f out of spec. The thermistor is measuring correctly but I noticed the ref voltage appears to be off. With the thermistor wires attached it's reading ~3.4vdc with the thermistor disconnected it's around I9.8vdc. my understanding is the temp is read off the resistance from the thermistor which leads me to believe the issue is with the ref voltage.
Another observation is the temp setting and readout at lower temps is way off meaning the oven thinks room temp is 300f and bake relay doesn't engage unless temp setting... -
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The motherboard does not POST and has the following symptoms:
When the power button is pressed, the fans and RGB turns on.
When the power button is pressed, the motherboard voltages 12, 5, and 3 are connected.
The motherboard does not beep.
None of the diagnostic LEDs light up.
USB voltage is off.
VCORE voltage is off.
The BIOS software was downloaded from Asus site and installed using the Q FLASH button, but it made no difference.
I would appreciate it if anyone could guide me on the cause of the problem.
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