can some kind soul tell me how the back light circuit is controlled in this universal combination board. i'm new at this but i know how to use a meter.its almost impossible to work out this circuit tracing solder runs on double sided board. i have figured out that the backlight output is what APPEARS to be a rectified ac output from a transformer.what feeds and controls the input is a mystery.any responses are welcome
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Re: backlights in tp.vst59s.pc815
You need to give more details and pictures so we can see what we are dealing with.Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
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Hi,
I am repairing a ups which doesn't turn on ,it has the following ICs:
SG3525 used to drive inverter mosfets.
couple of uc3483, one for the power supply and another to drive a big mosfet at the output stage(i think the technique is called boost)
A LM358 and TL074 for control mechanism and of course the uController.
The SG3525 is shutting down every time the ups is turned on.
I want your help to know the function of LM358 and TL074 in the system.
I reverse engineered the LM358 circuit and i think that one of the block(A) is used for battery level... -
Hi friends of electronics
What you see in the video and pictures attached is the circuit for charging the batteries of a DC motor.
The problem is that this circuit cannot charge the batteries (3 1800mAH NiMH batteries) any more. When the circuit was OK, its green LEDs lit up one at a time to show that the batteries have charged more. But now that the circuit is flawed, LEDs light up as you see in the video and at the same time successive beeps are heard.
Please help me fix this circuit.
(the datasheet of the IC: https://pdf.datasheet.live/28... -
Hello friends,
Looking for some guidance here. The RAM voltage circuit on this motherboard keeps burning out PU301 which is a RT8231AGQW. Copy of the board with the burnt chip attached with some voltage measurements and copy of the schematics also included.
I think I've checked almost every component in the circuit, but when I change the RT8231, the laptop starts I have 1.2V on the inductor for about 10 seconds and then the RT8231 goes south and no more voltage on the inductor. All other voltages on the laptop are good, this is the only one conking out for a reason I... -
Hello.
I have seen a short circuit tester made with 3 * 9V batteries, a voltage limiter component and a resistor connected to the probes of a multimeter.
The theory is that the meter becomes sensitive enough to read very low resistances and the lowest resistance to ground on a circuit is likely to be a short circuit in that area.
Link
The Amazing $1 Short Finder Upgraded! Convert ... - YouTube
https://www.youtube.com/watch?v=0eixDdCpiO4
My multimeter isn't normally sensitive to very small resistance, but when I put a 1 mega ohm resistor... -
Hello. MSI B250 Gaming M3 board, short-circuit on the power supply. Found a problematic mosfet VQ1
(N-PK616BA_PDFN8-HF) soldered it out - short circuit is gone. I replaced VQ1 + VQ5 (N-PK632BA_PDFN8-HF). VQ1 was replaced with PK618. After starting attempt VQ1 is lit again. What can be the problem? In the driver?
Schematic and Boardview here
...04-04-2025, 03:57 PM
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