This DVB Digital Video Broadcasting receiver was brought to my shop by a customer and a friend of mine. She said that the receiver was working fine and suddenly there was loss in electricity in the house and when the electricity was restored, the receiver stopped working.
I plugged the receiver into the electricity outlet and nothing happened. The receiver was dead. This receiver has two LEDs. One green for power indication and orange for satellite connection confirmation. None of these lights were on which gave me the indication that something is wrong with the power supply. Upon opening the receiver, and scanning the component in the power supply, I could not see anything wrong with it not even a bulged capacitors. So, the testing begins.
The main fuse was intact and this gave me indication that the bridge rectifier diodes are ok as well. I plugged in the receiver and started voltage testing in primary section of power supply. There was 300 volts reaching the main capacitor but nothing at the secondary output diodes. That told me something, that the main problem is located in the primary section of the power supply.
I discharged the main capacitor and tested it along with the power IC with the blue ring tester. There was no lights in the meter indication a short in the power IC 1M0380R. I took the main power IC off the main board and checked it out. There was no indication that there was something wrong with it but I replaced it anyway because of the reading that I got previously on the blue ring meter. I powered up the receiver and the power came on but there was no picture and the orange light was flickering and that was not a good sign.
I took the main power supply board off and started checking all the capacitors in the primary and the secondary section of the power supply. The reason I did this because I checked the voltage readings at the output of the sockets that connects to the main board and the most of the voltages were fluctuating. The first thing that came to mind is the capacitors.
I found about 9 bad capacitors there. Three capacitors: 100uf/25 volts. Two 47uf/50 volts. One 470uf/25 volts. Two 220uf/35 volts and one 1000uf/16 volts. I replaced all of these capacitors and I attached the power supply back to the main board and fired up the receiver. The green light was steady and the orange light was steady too. To make sure the receiver actually work was to plug it in and see if you have sound and picture but before I did that, I tested to make sure that I have 13-18 volts at the receiver Dish in socket. There was 18 volts reaching that area and that is a very good sign. That is an indication that I have a connection between the receiver and the LNB on the roof connected to my satellite dish.
I connected it to my TV set and powered up the receiver and the picture came on with sound. It was a lot of work but seeing the receiver comes to life was worth the time effort.