Ubiquiti Radio Hardware Repair: A Comprehensive Service Guide

 In my earlier Ubiquiti radio antenna repair note repairing Ubiquiti Lite AP 120 I said that I checked the various components on the PCB board. I checked the voltage regulator IC, the capacitors and inductors for any short circuit. I also posted Ubiquiti Lite AP 120 repair video on YouTube, but that video only showed how I checked the various components on the PCB board. There was comment asking where the actual repair was. I did not have time to upload and write about it but today I wanted to share how I repaired it.

After I checked, I found that one of the capacitors was short circuit. So, I knew it is something there.

But closer check of the capacitor alone it was reading fine. Then I realized that one of the IC connected to that short-circuited capacitor might be actual fault component. At first, I did not know what kind of IC that was or what the function of that IC was. I also did not know the name of the IC otherwise I would have checked online. One thing I learned is that checking the capacitor for short-circuit tells that the IC to which it is connected to or rather is part of the IC supporting component

However, I managed to find out what that IC was. It was a voltage regulator, more specifically a buck converter. Once I was sure it was a buck converter IC I searched for suitable replacement. After researching for a while I concluded that I could use the MP1548 buck converter IC.

Although I found it, it was difficult to find the IC to buy where I live. So, thinking for a while, I searched for the IC that comes in module. The solution was to use the MP1584 DC to DC Buck Converter module.

Then I had to figure out how to connect and what is the input and output which was easy because of the internet. I used the MP1584 IC pinout explorer to get to know the IC. This free interactive IC explorer makes easy to learn about any IC rather than reading large complex datasheet. There were only the input and output which I had to consider.After figuring these out, I desoldered the damaged voltage regulator IC from the Ubiquiti radio PCB board and soldered the MP1584 voltage regulator. After a bit of researching, I found out that the input terminal of the MP1548 buck converter should be connected to Vin (input pin) or the 7th pin of the desoldered IC. The output terminal of the MP1584 should be connected to the SMD capacitor terminal. This is as shown in the picture below.