The soft start circuit get the power supply form the AC, through the big black cap, the 100R resistor, the diodes bridge rectifier and smoothing cap to get a DC supply and then zener diode to do the voltage regulation for the circuit.
(Danger AC all over the PC board) Please check the power supply voltage stable or not, the relay is a 12V relay you can test the coil voltage if it got a 12V supply.
(Danger AC all over the PC board) Please check the power supply voltage stable or not, the relay is a 12V relay you can test the coil voltage if it got a 12V supply.
What's the issue you have with this device? What are you trying to say with »clicking nuts«?
Best regards!
Best regards!
The device worked well for the last 2 years then started to misbehaving . I can get a new soft started but do want to work out the problem and trying to fix it.
Quan
Could be a failed e-cap that filters the supply to the timer/counter and relay drive. I guess the CD4060 operates as a timer by counting down its onboard oscillator, and after predetermined oscillation cycles an output goes out to turn on the relay which in turn bypasses the NTCs. That timer output also turns off the oscillator so the timer stops there from that moment on. If the supply filter cap fails, the circuit can experience constant power cycling and the oscillator/counter would reset and restart repeatedly.
Yes, it is very low. Please also measure the voltage on the smoothing cap after the bridge rectifier.
If you still using the 0.22uF cap in your board then you will not get the correct supply voltage, it need at least 1.5uf (220V AC). Please change the cap to its orginal value.
Hi Patrick, i think it is the original cap. I swapped out the cap for another 0.56uf X2 cap and it is working fine now. I will find a larger cap to replace to ensure adequate function. Thanks Patrick.
Quan
