LAB-1 Multimeter and power supply non-functional

I have a Velleman LAB-1 3 in One lab device; serial# DK09052869. It is out of warranty. I recently got it out for a new project I am building and found only the soldering station functioning correctly. I have not used it for a few years and all was fine when it stored it.

With main power ON, the digital screen backlight does power on, however with the exception of the OFF switch position the display always shows 998 (decimal in various places dependent on switch setting).

Regulated Power Supply
With main power on, the power supply POWER LED is ON, however the illuminated ON/OFF switch does not light when toggled and the output connections do not supply any power in any switch setting.

I have checked the fuse above the mains connection; it is okay.
I have checked the fuse on the back of the multimeter panel as instructed in the user manual; it is okay.
I was unable to locate any other fuses nor detect any damaged parts with a visual inspection.

Is there anything I can do to put the unit back into operation? Is the 998 value an error code of some sort?

I’m sure you did it already but I will ask anyway.
Did you change the battery in the multi meter?

The switch on the power supply does not glow.

Yes, I did replace the 9 volt battery in the multimeter. I used a new one I had just opened. I will check to make sure it is actually a good one and not old/depleted from sitting on shelf in store too long.