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Damn... So that being said I never should have had my DMM reading mA to begin with. Could I have killed something somewhere by doing that? I had it set to measure voltage initially but for whatever reason when I started biasing, I switched it over to mA...
I'm guessing that the diodes have absolutely nothing to do with this even where I initially powered it up with DR1A and DR1B bass-ackwards?
-Chris
That's correct. As Beerguy said, a DMM set in current reading mode has almost zero resistance (it would affect the current readings if it did). So connecting one in parallel - as you would if you simply touched two probes to a part or test points - effectively creates a short circuit.
Yes, the rectifiers (the giant diodes) being reversed probably caused the fuse to blow. I doubt seriously that it would've caused any damage further down the line, though. As for the smoke that you got most recently, as Beerguy says, that's a bad sign. I'm hopeful that the smoke came from the DMM or from the test points themselves in contact with the probes. You didn't say where the smoke came from, so I'm assuming the best. Most everything is fairly robust in the MOSFET-MAX, save for the smaller transistors. Even those have to heat up and smell bad before they're ruined. A momentary spark and puff of smoke is much better than a high-temp meltdown, which can occur if you have the buffer bias set too high and leave it there for awhile.
We just need to find out what you may have damaged in doing this. I'm not sure where you are with this right now, but I would assume that everything's OK, first, and then start taking measurements - voltage (with power ON) or resistance (with power OFF) only.
BTW, measuring resistance on the power supply will involve some capacitors - that's why the meter takes awhile to settle. The DMM is actually charging the capacitors when it's measuring resistance. It will be the same with the MOSFETs, since they have a capacitance built-in (charging and dis-charging MOSFETs is a way to test them).
Try going back to the test points first to see what they measure in voltage. Start with the power supply - do you get some voltage and can you adjust it? Then move on to the tubes, then buffer, etc.