Look up the part numbers on the components themselves. I can assure you that they are readily available from places not named PG. They are made in a factory with a bunch of diffenent Brands. If simply trying to repair the knob you may be able to use another knob from different Manufacturer if it takes the same jack for wire.
Probably the power is not received by the heating coil, check fuse near the power cable (inside the flap on the iron bottom), or sometimes there is fuse in the power pulg of the power chord. It is rarely that the lamp is blown
Most mono amps now a days give you multiple terminals. The older amps were a pain trying to stuff all the wires in one set of terminals. If the amp is rated at 2 ohms mono then make sure what ever configuration of speakers your running does not go below 2 ohms using both terminals. For example do not hook a 2 ohm load to each terminal. 2 ohms period between the 2 sets of terminals.
Disconnect all speaker connections and rca cables. Leave power, ground and remote wires intact. Try turning on again. If you still have a protection light your amp is faulty. Hopefully you have warranty .
Please check speakers impedance
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for better power yes one ohm but amp must be 1 ohm stable.and both subs will have to be 4 ohm subs to get the 1 ohm needed .If its a class D amp both speakers outs are bridged internally so either is ok to use look see if there is a bridging line on speakers that runs from one side to other and will say bridging. if not any side will work.a manu would help you find yours or you can look one up online.al