Keysight DSO9404A oscilloscope repair failure case

Fault phenomenon:

The touch screen does not work properly after the instrument is turned on.

Testing process:

The instrument has a touch screen failure. Many people may think that the screen is broken. Let's take a look at the specific problem. After disassembling the machine, it was found that there were screws falling inside, which came from the acquisition board. There were traces of tantalum capacitors bursting on the acquisition board, which had been repaired, and there were signs of parallel chip capacitors in many places. After testing, the instrument acquisition board had repairs in many places, and the touch function control circuit was damaged.

Repair process:

Replace damaged components, restore man-made faults, and test instruments.

Repair results:

After replacing the components, the instrument returned to normal performance, the touch screen could be used normally, and the repair was completed.