Instek GPS2303 - screen panel slowly died

[f0raster0]

Hi guys,

We borrow a lab supply Instek GPS2303, and we broke it :-(

https://www.eevblog.com/forum/reviews/instek-gps2303/msg97795/#msg97795

We were using this for some testing and got some unusual results. The screen panel slowly died and then went blank. We tested output etc afterwards, and everything else appears to be working.

Inside everything looks "OK",
Do you have any tips, idea to start debugging it, looks like just the screen panel is not working.

thanks very much

[Gyro]

Welcome. 

I'm curious about the 'slowly died' bit. What were you testing on the outputs?

I killed the displays on mine once, but that was by accidentally applying an excessive voltage (up to 1kV) between the two outputs and also relative to ground (Don't ask! ). I'm just wondering if you did something similarly silly.

There are separate supplies to the two channels from the transformer to drive the control circuits. Each display is driven by a standard ICL7107 DVM chip (4 total).

[Ordinaryman1971]

The front panel is powered from separate winding on the transformer... I would first check if you have AC coming to your front display assembly. After this it's very simple power supply... check fuse if there is any, check rectifier, regulator and so on. It shouldn't be lot of checking.
I have one of those but I've never taken it apart.
So, if I'm correct the power supply is still working you just can't see the settings for the channels?