Not everyone agrees with me, but I say, replace everything you are willing to. This is not an old Marshall/Fender where original parts vs. updated parts or "stock" makes it more valuable (and hence an piece of gear for home play, a collector).
You can figure out what cap is what by following a schematic, the parts numbers are labeled on the board accordingly.
One thing I don't think I've mentioned before--reflow the solder, or remove and replace the solder on all the PCB tubes. Not too long ago I was getting an occasional intermittent issue I couldn't figure out. When I finally got it to the bench I removed the ancient and cooroded solder on the pcb pins 3-6 pins at a time, cleaned the joints (as pure an isypropyl alcohol as can be found and a stiff brush, check tubedepot), then resoldered the preamp tube pins, then last but not least, applied pressure to the tube socket while I reheated each of thee solder pins to make sure the sockets were as close to the board as possible, given that they can get wiggled/cracked etc over time. I think it's good practice for pcb-mounted tube sockets, and whether it was coincidence or the issue, I haven't had anything cut out since either.
You also have some serious burn marks on that board. If you are willing and able to do the work, buy one of the new main boards available from orville amps and save it for the day you have more trouble with arcing, or just do that from scratch. You'll be glad you did if you use this amp regularly. Easier to populate a clean board than it is to desolder old components and resolder new components on the old board if you are going to do more than a handful of components.
Only trouble is being extra sure of where your wiring points go to/come from, easy to get lost unless you take the time needed for when you get a little lost.
You can figure out what cap is what by following a schematic, the parts numbers are labeled on the board accordingly.
One thing I don't think I've mentioned before--reflow the solder, or remove and replace the solder on all the PCB tubes. Not too long ago I was getting an occasional intermittent issue I couldn't figure out. When I finally got it to the bench I removed the ancient and cooroded solder on the pcb pins 3-6 pins at a time, cleaned the joints (as pure an isypropyl alcohol as can be found and a stiff brush, check tubedepot), then resoldered the preamp tube pins, then last but not least, applied pressure to the tube socket while I reheated each of thee solder pins to make sure the sockets were as close to the board as possible, given that they can get wiggled/cracked etc over time. I think it's good practice for pcb-mounted tube sockets, and whether it was coincidence or the issue, I haven't had anything cut out since either.
You also have some serious burn marks on that board. If you are willing and able to do the work, buy one of the new main boards available from orville amps and save it for the day you have more trouble with arcing, or just do that from scratch. You'll be glad you did if you use this amp regularly. Easier to populate a clean board than it is to desolder old components and resolder new components on the old board if you are going to do more than a handful of components.
Only trouble is being extra sure of where your wiring points go to/come from, easy to get lost unless you take the time needed for when you get a little lost.