Rigol DP832 Not starting up

[deon]

My 5 year old Rigol DP832 was working correctly despite the occasional resets.
However, tonight it reset and never started up again.
The output wasn't connected to anything when it reset.
The display backlight is off and doesn't beep on startup or respond to any keys.
The cooling fan runs at low speed, so there is power to the unit.

Does anyone have any ideas?

[thm_w]

Does your unit have the original "hot" regulator issue (see the old thread if you're not sure)? Perhaps it burned itself out, and since it powers the CPU section, it won't boot up.
There are also a bunch of through hole fuses on the PSU board, I would go through and test those. Along with usual voltage testing.

[torcek]

Did you manage to solve this issue?

[Proto]

Since you fan is running slow, consider the following:

I tried replacing the fan with a quieter unit and the control circuitry noticed the current drain was below a threshold so it would not energize any of the outputs.  I was going to apply additional loading but since it was under warranty at the time, I switched back to the original fan.

I don't remember if it flagged a fan fault on the UI.

[ldemers]

Well.. mine now also refuses to boot. It lights up, fan starts, screen stays blank.  As suggested by Rigol, I started while pressing help, and was able to boot. But that worked only once.  Any suggestions ?

[MR]

This is pretty old but I'm using this PSU every now and then as well.

Some issues:
* The fan blows in air through the metal enclosure and there's no filter, it will throw corroded metal dust onto the PCB (the metal enclosure will corrode over time in that area). In humid areas this will kill the Vias on the PCB (it took 3 years to kill the Vias here). During summer time we have around 65% humidity here.
-> Workaround conformal coating on the PCB & on the enclosure of the power supply, add solder to the PCB vias in the affected areas (I was able to recover it that way)
++ Issue that lead to checking the PSU, channel number two started to display wrong values, when setting channel two to 5V it showed 12V and also output 12V.

* The Freescale Microprocessor is powered from an undersized LDO, this one should be replaced with a switching regulator.
-> Caution when disassembling the PSU and powering it on the regulator depends on the airflow, if it's not getting cooled it can even burn one of those fuses (it did it here). When I replaced the regulator with a switching regulator, that switching regulator was also faulty and dumped 12V instead of 5V to the front panel which burned the processor, I was able to recover the system by replacing the BGA and one 249 Ohm resistor on the board.

I got a dark screen when the BGA wasn't soldered properly, and possibly when the flatflex cable to the frontpanel isn't installed properly.
My PSU works properly again after servicing it.

[Smokey]

https://www.eevblog.com/forum/testgear/rigol-dp832-random-reboots/msg2949816/#msg2949816

[MR]

Ya I also read about that one, but my problem was mainly caused by the disappearing Vias on the PCB directly next to the fan.
It's kind of a trap if you open it for debugging the mentioned regulator might kill a fuse and the MCU will not start up anymore.

I never had any sudden reboots, only the wrong output on the second port. The datasheet says that the humidity of 65% is still within range (5% to 80% relative humidity) well until the warranty ends.