Testing an RF Famicom with an Arduino Mega 2560

[CodeApeMan]

Hello everyone, I recently bought an RF Famicom that only outputs a black screen. Can I do any tests on its hardware, having only the console, an Arduino Mega 2560 clone, a computer to program the board, a TV to output the picture on, some wires and a soldering iron?

The main board is HVC-CPU-07.

I have a few cheap Chinese Famicom (Dendy) single black blob cartridges, but I don't know if they're working.

[gorgyrip]

I don't know what you want to do with the arduino and I haven't fixed a nes/fami in a log time, but first you should test your carts or get a known working cart. Next, mod the console for AV. For a weak signal you can get video from one of the wires that goes from the main pcb. Also check to see if the chips get 5v. Check for broken/damaged traces.
Some TVs don't play audio if there's no video. Use some other method, like headphones to check if you have audio.
If you have audio, then it's either the ppu, its sram or its logic. Find online nes/famicom schematic.
PS: a nes without the cpu will display a white screen (if the ppu is ok)

If the cpu or ppu is dead, you'll have to replace them both with clones from ali. Both, because those are pal. Also you'll need to replace the crystal.

[Volo]

Well, you may make Arduino Mega 2560 into an oscilloscope, which may help debugging.

If you are sure that power rail is OK, use your improvised oscilloscope to check if there is characteristic NTSC video waveform on pin 21 of the PPU.