I have 3V3 and 5V onboard, something is happening, but I have no clue.
Any advice will be appreciated
Should i try flasing bios, is there dump for it?
Trofazni
Senior Member
Last Activity: 01-23-2025, 01:13 PM
Joined: 12-30-2016
Location: Kikinda
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Lenovo L340-15IRH blinking power button
Hi, i got this lenovo on service, power buton is blinking for some time, but then stops after a minute or so. Allo, when battery is plugged onto mb, laptop charges for a minute at about 25W, then stops for a few seconds, and the cycle repeats. Laptop was already tried to fix by someone unknown, I can see bios chip has been messed with, i can see it has been soldered.
I have 3V3 and 5V onboard, something is happening, but I have no clue.
Any advice will be appreciated
Should i try flasing bios, is there dump for it? -
Re: Vestel 17IPS62 power supply dead by lighting
Sadly no, even changed 741 and Optocoupler on secondary, did not have luck... -
Re: Identifying IC & troubleshooting TP.MS3463S.PB782
I too do not know if it's that one, but l found simmilar 0cl 308 b4 marking, and gave it a try, of course when i removed old one that was fried, indeed, measuring on green picture.
Replaced it, 15V was not steady, no stb power or 12V rail.. Changed optocoupler, and diode on secondary side of optocoupler, you have red cicled on pic what was changed. Anyway, it's working now, thank you for leading me to another succesfull job
TV tuner seems to cant find any channels, i guess thunderstorm fried...Leave a comment:
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Identifying IC & troubleshooting TP.MS3463S.PB782
I have trouble with this psu, l'm suspecting pwm ic is the problem, but i can not find it's datasheet, or anything. The picture is from service manual of tp.ms3463s.pb801, mine board is pb782, l'm guessing it's similar, if not exact as mine.. So what is UB101?... -
What are typical problems with this kind of psu behaviour?
It is ordinary 12V 5A psu, everything measures ok, what could be problem?
[url]https://youtu.be/-zwaUHZ2OCk[/url]https://It is ordinary 12V 5A psu, e...aUHZ2OCk[/url] -
Re: Samsung 24" power supply BN44-00195A
Ok, so the problem was in one zener diode on error amplifier, it should be 27V, but it had leakage... 9V. Shouldn't pass voltage under 27. On multimeter testing diode has voltage drop within range, but voltage check did not go that well, and it reports fault in psu and shuts down.. Removed it, and put 2 zeners in series, 13V and 12V, and its working, and fault circuit is once again working You have details on pictures.. How i found it, when psu shuts down? I applied external 24V directrly to 24V psu rail, and measured... This is the...
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Re: Samsung 24" power supply BN44-00195A
It does not matter if it's connected or not... PSU should stay on even if inverter board is disconnected...
They are ok. Problem is not that obvious, I THINK I checked all of usual suspects..
It's ok.
It's in the picture...
Last edited by Trofazni; 03-01-2019, 02:04 PM.Leave a comment:
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Re: Samsung 24" power supply BN44-00195A
Yes, tested it with one of those ebay "LCR-T4 ATmega328 Digital Transistor Tester LCD Capacity ESR Meter" which works really fine btw, cappacitance is 11n tested. Also CM809 47pF/1KV beside him is ok. Measured esr of electrolytic caps in that area, also ok.
When turned on by button press, MC33067 gets 15V, 24V rail gets some Voltage, and that is it. IC is still on steady 15V, but its like it does not oscilate. Also, changed that IC along with fet change, but i have soldered another one mc33067, and new...Last edited by Trofazni; 02-13-2019, 06:29 PM.Leave a comment:
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Samsung 24" power supply BN44-00195A
So, we meet again badcaps
I got monitor with psu mentioned, that was in some repair shop, but they tried something, with no sucess, and it came finnaly to my hands.
Problem was (or is still) on primary side, QM802/803 were short, as well as driver MC33067p, along with fuses, resistors, etc.
Changed all that I found faulty, but still it does not run. What you can see in a video, is psu+logic+pwr on/off button, without backlight or monitor connected.
As I switch it on, by pressing power button, pfc is working and steps up to ~390V, 5VSTB is steady,... -
Re: Lg 47lb582v blinking backlight
Ok, I solved it.. First I tried to swap power lines of 2 strings, came out the same situation.. So, I guessed that NEW strings are not working. Soldered 10 leds on a test board to imitate string and it worked. One of two new strings was bad. As i tested it, found out that one of 4 half strings (two A and two B), is making problems. When I isolated problem to only one half of string, I tested each diode, and they worked??? Checked for shorts to ground and else, all ok.. Finally I removed test leds, and suddenly everything is working without any...Leave a comment:
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Re: Lg 47lb582v blinking backlight
I will try that, although every single led in repaired strip is tester separetly, from begining to the end, even every one*s resistance to the chasis.. all measuring as should.
I will replace power lines of strings and write tomorrow when I get to work..
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Re: Lg 47lb582v blinking backlight
Hi to all!
I will jump into this thread, because I have the same problem, on the same power supply.
Anyway, leds are ok, one string replaced with new, second repaired, tested, and ok.
When it flickers, only the old, repaired set of leds is blinking, new installed does not. So, one of two power supplies for leds is faulty on pwboard. Checked caps, diodes, resistors, checked for shorts, everything seems ok, so I guess I am missing something.
In my opinion when leds died they draw too much current or made shorts and burned...Leave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
There is no u3, or I don't see it on board?
Voltages are on screenshots in post before, i get ~2-3V on 12V...
OC is ok, tested, even changed...
...
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Re: Vestel 17IPS62 power supply dead by lighting
Driver for fet on primary side? Yes, it's gate was shorted to ground... I litteraly do not have any ideas......Leave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
What do you mean and set switch off? I don't understand.
Diodes are measured when removed from the pcb.
D9-0.231mV
D7-0.236mV
D8-0.224mV
D23-0.419mV
D24-0.433mV
D25-0.405mV
To chasis:
X L4 - ~30k
X 24V - 1.7M
X 24V_AC - 1RLeave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
6cw02 is marking on it, it should be BC817
[url]https://cdn.badcaps-static.com/pdfs/fb0f3dda997d099e99ca803c43bf696b.pdf[/url]
Screenshots of voltages are uploaded...Re: Vestel 17IPS62 power supply dead...re uploaded...Re: Vestel 17IPS62 power supply dead by lighting
...Leave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
They are ok, all 3 of them are 39K, as are markings on them.
Yes, you are correct.
Measured it with esr meter, also tried to replace. Same thing, it's good cap.Well, as you mentioned that, there was fault on secondary side, but i solved it before aknowleging that the primary side if faulty, too.
Transistor Q5 that drives optocoupler was damaged, so i replaced it with another npn small signal transistor. Also checked resistors around him, one faulty, replaced. OC feed is ok, pulsing with primary...Leave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
Changed it with 18V one, same thing happening. Optocoupler has 0.135 voltage drop across pins 3 and 4 when 1.2V is applied to pins 1 and 2, so I guess everything is ok, but it is not working...
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Re: Vestel 17IPS62 power supply dead by lighting
Yes I changed it with the fet togeather.
C75 is 26pF according to tester. On schematics is 10pF, so I assume that is ok.
I do not have D26 on PCB its d36 across electrolytic cap? Anyway i checked it, voltge drop is 0.56V.
And let me correct myself, drain to gate is 277kOhm, drain to source 160k, but gate to source is 385 Ohm.
Also, on IC controller FAN 6300A, it's gate was short to it's gate, 8 Ohm.
Anyone can explain what I asked about...Leave a comment:
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Re: Vestel 17IPS62 power supply dead by lighting
[url]https://www.youtube.com/watch?v=y_q_3oRd7Rk[/url]
This is voltage across IC ground and HV pin 8.Re: Vestel 17IPS62 power supply dead... and HV pin 8.Re: Vestel 17IPS62 power supply dead by lighting
[url]https://www.youtube.com/watch?v=y_q_3oRd7Rk[/url]
This is voltage across IC ground and HV pin 8.Leave a comment:
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