Power Supply Failed Again – TCL L32D2900 (Part 2)
The TCL L32D2900 power supply failed again. Learn why the power supply was troubled. The customer told me on the phone that my TCL was not turning on again. Ali, bro. I immediately ordered the TV workshop, and if the TV switched on and its standby light was on, I turned the unit on from standby mode so it started working perfectly. The customer was also surprised I told them to leave it to me; I would test it. It may be that there is something wrong with him. Their kindness that they cooperated with me.
Repeated Power Supply Failure Case
This TCL L32d2900 model had a power supply blast when I first came to it, which I fixed. Again, when I set it, it would turn on its power supply when it switched on. I turned it on to test it, and this unit worked perfectly well; the picture and sound were OK. Then I turned it off and turned it on again, so its standby light did not turn on, meaning the power supply did not work. I would advise you to make this fault also and read the first part so you will understand better.
Why Did the Power Supply Fail Again
The TCL L32D2900 power supply failed again. Why did this happen? Now I had to find out the reason why the seat was turned on the first time but was not turned on after turning it off again. The main twelve voltages of the circuit were also perfect. The VCC of the PWM IC was also 18 volts. Correct the PIN number of the main IC in the 3 RT pin original circuit. This pin was connected to the main DC volts to the positive voltage through a series of resistors. I saw this cut the connection and grounded the resistor of the 47k.
OB2273 IC RT Pin Explained
With the resistor on this pin, the eye is told at what speed it will switch; if the resistor is damaged, the power supply will not start. This pin sets the IC’s operating frequency, which is set from 60 kHz to between 130 kHz. This was the reason why the power supply in my case would have started once, but the second time the IC frequency error caused the problem when I set the perfect value. When I grounded the resistor with this pin, my fault was fixed.
How We Modified the RT Pin – OB2273 IC
How I modified this PIN according to this IC I showed it in a picture below. You can see where the circuit was cut from where the resistor was grounded. I think that this circuit had another IC of the same original series, and I had replaced the original OB2273 IC. The need for this modification occurred because I will write a comprehensive article on this IC next time because it is a common PWM modulation IC.
Conclusion
The TCL L32D2900 power supply failed again. This article was related to the power supply fault of the same model that was repaired by Leo in the original condition, but this power supply had to be repaired again with a different fault. Be sure to see and read the first part of this case. Sony LED TV Repair Center Lahore fault-finding articles repaired with my own hands, fellow technician, will continue to be published to help.
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Shaukat Ali has over 30 years of experience in LED TV repair, specializing in chip-level repair work. He is an expert in Sony LED TVs, and also repairs other major brands like Samsung, TCL, Orient, and Haier. His expertise includes display panel faults, motherboard issues, power supply circuits, T-Con, and HDMI faults. Based in Lahore, he shares real-time fault finding cases from daily repair work to help technicians and learners with practical experience.
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