I’m currently negotiating a used SWR amp and 410 cabinet. I’ll pick it up soon and wanted to get your knowledge on what to look for and ask when picking up used equipment. I will be able to test it and play a little to make sure it works well. Things I know to be aware of: water damage, cracks and bumps, sound, make sure all the knobs turn smoothly and don’t introduce noice to the signal… thanks in advanced for your advice.