SMPS Repair Step-by-Step – No Output | KA3842 VCC Fault & Current-Limit Resistor | #1076

In this video SMPS Repair Step-by-Step – No Output | UC3842 / KA3842 VCC Fault & Burnt Current-Limit Resistor | #1076/ 12V 10A SMPS Repair, Burnt VCC Current-Limit Resistor
In this video I repair a 12V 10A SMPS that had no output. In thhis KA3842 PWM controller base switch mode power supply, the SMPS Controller IC damaged internally, it caused to burn VCC current-limit resistor, located after the auxiliary winding rectifier. Because this resistor failed, the KA3842 could not maintain stable VCC — the VCC pin was fluctuating and the reference voltage dropped to ~0.7 V instead of the normal 5 V.

After replacing the KA3842 IC and the damaged VCC current-limit resistor, the reference voltage stabilized at 5 V and the SMPS started operating normally again.

This repair covers:
Diagnosis of KA3842 VCC instability
Checking the auxiliary winding rectifier and filter
Testing VREF (5 V reference) and confirming failure
Replacing the VCC current-limit resistor
Replacing KA3842 controller IC
Verifying 12 V output and load stability
Full step-by-step SMPS repair workflow
#SMPSRepair
#SMPSTroubleshooting
#ElectronicsRepair
#haseebelectronicsurdu
#SMPSNoOutput
#CurrentLimitResistor
#SMPSFix
#PWMController
#3842Test

Видео SMPS Repair Step-by-Step – No Output | KA3842 VCC Fault & Current-Limit Resistor | #1076 канала Haseeb Electronics Urdu