Repairing a Dead Mini Oscilloscope

These mini oscilloscopes are sold over the internet in either kit or assembled form and for the price, work pretty well. One day I went to use mine and it wouldn't turn on. I checked the adapter and it was putting out the proper voltage. Rather than immediately throwing it away as many people would, I opened it up to see if there was anything I could do to fix it.

1) Phillips #2 screwdriver

2) Long nosed pliers

3) 30 watt soldering iron with fine tip.

4) 40/60 rosin core solder with a diameter as small as possible to allow for easy soldering of surface mount components.

There are 4 Phillips screws on the back which come out. In the pictures, you can see the display circuit board connected to the input board by a plug in connector. The two boards can be separated by starting by starting from the bottom and gently forcing them apart. There is a metal spade type connector that goes through the top plastic, it can be gently eased out of the plastic by moving the display circuit board in a side to side motion while pulling gently in the down direction.

Once the pieces were separated, I plugged in the adapter to the display board and wiggled the connection to the board, momentarily, the display came on. I checked the female plug connector that was mounted on the circuit board and noticed that it was loose, the solder job was very poor and not making a connection any longer. It just needed to be resoldered. As can be seen in the picture, the top left black connector has three pads that needed to be resoldered.

Resoldering the two top pads and one lower pad on the female power connector. Once this is done, check to see if any other connectors that come from the outside are loose. Especially resolder the spade type connector that protrudes through the plastic on the top of the scope. Before reassembly, plug the adapter in to see that the scope turns on. Once this has been confirmed, reassembly can be done.

Reassembly is the reverse of disassembly. Take care putting the spade connector through the slit in the top of the case and line up the connector on the back of the display board so that it plugs easily into the input board. Once the pieces are put together, the scope should function as before.