Hovering board power supply repaired. Model: HLT-180-4202000

A lady from next door brought this power supply for repair. She explained that she heard loud noise when she plugged into power.

In my country, these kinds of chargers are hard to find and if we find one, It would be expensive.

There was no stand by and by seeing that, I guess there was a serious damage inside. The only way to find out is to open it.

There were no screws on the outside of the housing so I used the old fashion way; a sharp knife and a strong hand.

I carefully, traced around the edges with a sharp knife then with a flat screw driver, I was able to pry it open. From the first look, I could not see anything blown but…

When I checked where the fuse was, I saw some burnt marks there but I continued with the repair.

This is the damage found on the other side of the transformer. It looks nasty and it looks like there was a lot of damage, but…

After the cleaning of that area, it did not look that bad.

One of the coil pin was loose and that cause the sparks and the loud noise that the customer heard. Of course the main fuse was open.

Since the fuse was open, I directly checked all the components in that area. Luckily, nothing was blown. I was thinking about replacing the bridge rectifier although it was not shorted out but I did not. It is a standard procedure to change the bridge rectifier in cases like this but I decided not to.

This is the open fuse. It was 250 volts and 3.15 amp rating. Once I re soldered the pin of the coil and installed it back on board. I used the light bulb trick to see if there are other shorted components that I might missed while testing.

I powered the transformer with the light bulb connected to the fuse pins; and as you can see, there was no short on that transformer.

And in the process, I could see the power light on. To me, that was a very good sign. I soldered good fuse back on board and tested for power.

As you can see, the transformer is up and running. After making sure everything was fine, I put drops of super glue on the four corners of the housing and shut it tight.

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/ss8050-npn-transistor-open-circuit