Quoted from JiePieWie:
My D&D machine stopped working a few weeks ago. Last weekend i had the time to look into this and found out that FU3 was burned out so no 5V on the board. Before ireplace that 3AG fuse i ave to be clear on what kind of fuse it is: slow blow or fast blow. On pinrepair it's mentioned as a 6A SB but on the techsheet i have it's just a regular 6A so i assume a Fast Blow. On the actual schematics-booklet it´s a ´6AMP 3AG FUSE´ so no mention of FB vs SB.. What is recommended?
And i have no clue why that fuse blew. Are there things to check before i just replace the fuse and turn the machine on? I already checked the diodes D1-D4 and they are fine.
You might want to check the connectors on the board. Without knowing anything about your game, look for brown spots, signs of over-heating on the SDB, if you already have not done that. It could just be an old fuse. Did it stop working while you were playing it, or did you power it up and no 5v?
The tech chart I have just says 6A 250v for F3.
A recent fuse story from here: I swapped out some inserts from my spare playfield to the active playfield, and although I was extremely careful pulling out, and then putting the new ones in, somehow I ended up blowing the fuse under my playfield. Didn't bang anything, no blunt force trauma, just up and died. I have no idea how old it was, but it was on the game playfield when I got my D&D in 2007.
It may have just given up the ghost. I would check all of your fuses for continuity, while you're in there. Can't hurt, and it doesn't take that long.