A medical company located nearby brought me this device for repair. According to the man who brought the device, it powers up but the heater on the device when turned on, the whole power supply goes into shut down. In other words, the power supply cannot handle the load when the heater is turned on.

This power supply has three outputs as you can see in the photo.

According to the customer, this power supply is hard to find and he wanted this to be repaired as soon as possible.

When I took the cover off and looked inside the power supply, I could see some corrosion on the circuit board.

This brown stuff used to be white. The manufacture put this stuff on component when they make the power supply; with time this white paste changes into brown and become conductive. The first step was to take this stuff off and then check for dry soldering joints.

In this photo you could see the process of this white paste changes into yellow then brown.

 The second step was to look for dry soldering joints and I found lots of them on this side. I do not apply more solder to the dry joints without cleaning the joint itself.

I take the old solder off, clean it then add more fresh clean solder to it and that is a good process to maintain.

In this photo you can see more damage to the board. One resistor I believe it was 149 ohm was completely loose on both side of the tracks and needed to be fixed. I applied fresh solder to this resistor and I tested the device again.

The customer came after I called and he tested the device. I could see a smile on his face when he saw the display on the screen. He kept the device on for about 15 minutes and then put his hand on the heater and he felt the heat there; he declared that a repair. I was happy to hear that. Of course he paid generously which to me was a sign of gratitude and appreciation.

Mission accomplished.

This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.

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Note: You can check his previous repair articles in the link below:

https://www.electronicsrepairfaq.com/panasonic-cordless-phone-does-not-ring-when-receives-calls