Hantek DSO5202B freezing then restarting repeatedly

[Yansi]

Hello,

Yan here again. Few days ago, my old Hantek DSO5202B scope decided to quit. After running it a couple minutes, it freezes (either by itself, or by getting scared of a button press or so.  After being frozen and unresponsive for a couple of seconds, it restarts itself. And then the whole process repeats. It works for a few minutes, then freezes.

The scope is in an original DSO5202B, from 2013, not a hacked unit. Firmware update never done on it.

I've poked inside, cleaned the little bot of dust from there and replaced RTC battery (the original one had 0.2V). Anyway, that discharged RTC may not be anyhow related to the problem.

But what may be causing it? Anyone encountered this issue?  I am not sure if this thing is even worth trying to repair it. As a last resort experiment, I have downloaded a firmware upgrade from the Hantek website and tried updating. Well, it does not even see the file on the USB drive.   

Any suggestions please what I could try to diagnose the issue? I can only think of measuring the power supply ripple and voltages on all rails.

[tunk]

Bad solder joint?
It could be that it only see FAT partitions (and not FAT32),
but if it crashes during update then you may end up with a brick.

[magic]

IMO the first suspect in all electronics failures are supply capacitors.

I would never dare to attempt firmware update on a device that exhibits any kind of random behavior

[Yansi]

It's a useless brick already, what can I loose?  (time... likely hours of time...)

I have peeked inside (when replacing the RTC battery), the supply looked as a new one, but that look may sure be deceptive. 

I can measure the voltages and ripples. Will report back, but I don't expect there much to happen.