Alright I got a fresh problem - I got a Marshall JTM 30 from a fella for free with something else I bought. He said he thought it needed an output transformer and that he had already replaced it once. I get it home sit it in the corner for a month. Today I pull out the chassis. It's got both a Hammond replacement PT (290QX) and OT (1750NA). When I check the leads going to the primary they're super loose crimp connectors. I touch the secondaries... also super loose. This may or may not have been the cause of the supposed failure. So I pull out the OT and start poking around the multimeter. Each side of the primary from the center tap is even - 71 Ω. Open Circuit from the Primary to the secondary. I check the specs of this transformer and it's supposed to be a 6k primary w/ 8 / 16 Ω secondary taps. I use my variac and put 5.5 v into the secondaries. I get 80.1 volts and 110 volts. With that math @ the 6k primary I get an impedance of 15Ω and 28 Ω. Which isn't right, obviously. I can't help but feel like that numbers would be all out of whack and not proportional or there'd be a short between the primary and secondary if the transformer was damaged. Is it possible this thing was just wound wrong? Or is my math wrong? Maybe I'm skipping a step? Any other way to test an output transformer? Thanks!