Usually you should start with the power supply or power source. Without power, nothing is going to happen.

If a fuse is blowing, that takes special consideration.

You really need to have a schematic diagram or service manual for the device you are working on... and be able to read schematic diagrams.

At the very least you need a layout, which is a drawing of your device with part values and hopefully voltages written on it. Just do a search with the make, model and the words “schematic diagram” and you will probably find them for free somewhere.