Bad solder joint caused Rigol DS1054z button lights to randomly blink

[urill]

I bought this ds1054z two years ago. I started to see the weird button led behavior coincidentally after a firmware update and posted about it in the firmware thread. The problem was intermittent.

I tried to claim warranty, but rigol insisted that I had to pay the shipping.

Now the warranty lapsed and the frequency of the problem became unbearable. I opened it and found a solder ball that shorted two pads on the button board. The solder joints looked sad. The board had flux residue smeared all over. I resoldered the flat flex cable and fixed the problem.

I hope this post will help someone else with a poorly soldered button board flat flex.