That pump diode looks fine, those stripes are normal. High power diodes like that are actually a stack of lower power diodes so you get an output that has a bunch of high intensity stripes. Mostly why they fiber couple it, you want a nice round even beam for pumping the crystal and fiber does a good job of homogenizing the beam. Can't speak to the power output, as that's practically impossible to judge based on a photo.
Without being able to verify the output power of the pump diode the things I'd check for first are damaged fiber (any sort of contaminant on the ends of the fiber will result in it getting burned), then I'd check for damaged crystals. Too much power density in the wrong place can crack them, and KTP (the frequency doubling crystal that converts 1064nm to 532nm) is known to degrade with use, especially in higher power applications. I've seen cracked crystals lase, but not well. Contaminants on the faces can also cause issues, either cracking or burnt/otherwise damaged crystal faces. After that alignment could be an issue, and getting it right without practice isn't all that easy. Though from what I recall it is a fairly simple linear resonator with frequency doubling done outside of the laser resonator, which makes things a little easier.
A lot of the components in that head are the same as mine, but the layout is different and there's a couple things in there that my head doesn't have. Could you post a top down picture? Would make it easier to understand the layout.
Sent you a DM, you should hopefully be able to message me now. I'm far from an expert on this sort of thing, but hopefully I can point you in the right direction.
