I told you so!!!! Nah Nah Nah Nah. Now let's go back to bring it to a repair center....never, do the routine first, it's simple. Repair center woulda' got $500 out of ya, of course they woulda' put McIntosh tagged tubes and of curse, THOSE are better! Yeah, riiiight. You did exactly the right thing, fixed it yourself. J.V, when a lamp burns out do you call an electrical contractor and rewire teh service panel, just to make sure, teh breakers are OK, before you change teh lamp? Must be a govt' worker? Make it complicated, increase teh costs, pay too much. Keepo it simple, keep it mortal priced, then you enjoy it more, paying too much, is just that.
In audiophile land, solar flares sometimes make amps not function properly too. Get the Soloar Flare test kit from Fleece-M-Ind. Your Solar buddy. When there is a problem also escatlate it into a real nightmare, it makes spending money seem like it's high end! This is a high quality McIntosh amp, you can't just swap tubes, oh no, this is special, riiiiight. This logic is why overpriced stuff sells to the gullible.