in this video {522} How to Test SMPS IC Switching/ SMPS Switch Mode Power Supply IC Switching Test with Multimeter.
DOWNLOAD UC3843 SMPS Power Supply circuit Diagram / Schematic bit.ly/3jpm06C
during repairing a switch mode power supply, how we can verify that the smps controller / pwm controller is switching, we can test the switching of the pwm IC using digital multimeter.
smps #electronics
in this laptop charger repairing / troubleshooting i demonstrated the test process to verify the pwm ic switching. when pwm controller IC starts switching it drives the mosfet and provides switching pulse to drive transformer primary winding
we can test dc voltage across mosfet drain to source
we can verify voltage from vcc winding rectifier
we can check voltage from optocoupler
in last video number 521 • {521} How to Repair La... i demonstrated Laptop Charger repairing (DEAD) No Power Solution | How to Repair Switch Mode Power Supply SMPS, this laptop Dell laptop charger using UC3842 current mode smps controller ic, it had no power, when power was connected or plugged in, it was not powering ON.
when i checked the voltage on DC rail on bulk dc capacitor, these were 330VDC but there was no output. then i checked voltage on vcc capacitor there were no voltage. vcc voltage are the most important for function of any ic. so that was the reason that pwm controller ic us3842 was not taking start. (uc3842, uc3843, uc3844, us3845, ka3842,ka3843, ka3844, ka3845 ics have the same pinout in their datasheet). pin number 7 is vcc pin, it must have vcc voltage for 3842 ic, it must have 12 working vcc voltage. these vcc voltage were missing due to the reason that the startup resistor was burnt. it was not providing initial vdd or vcc voltage to the ic. i checked that the original resistor was 180K ohm. for test purpose i connected 310K Ohm. (we can use a higher value resistor, it will cause a slower start)
explained practical How to repair switch mode power supply SMPS very easy. i shared my easiest and perfect troubleshooting techniques practical troubleshooting. smps concept and troubleshooting repairing or understanding repair switching mode power supply basics and working principle. also i discussed smps basics. after watching this video you can capable to:-
how to repair smps
fuse keeps blowing
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if SMPS is dead or no output
if SMPS have fluctuating output or output voltage unregulated
if smps have short circuit in output
how to eliminate short circuit
how to troubleshoot PWM #SMPS controller when there is no switching from MOSFET
if SMPS have a whistle sound or excessive noise or excessive heat
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How to Test SMPS IC Switching
SMPS IC Switching Test with Multimeter
SMPS Switch Mode Power Supply IC Switching Test with Multimeter,
laptop charger repairing
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How to Repair Switch Mode Power Supply
How to Repair SMPS
uc3842 ic circuit diagram
Uc3842an,
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