I am by no means an expert. I am about four months into my AK education, but I have probably read a couple thousand posts and I can give you what seems to be conventional wisdom with the caveat that there is by no means 100% agreement on this. Electrolytic capacitors seem to have an expected life of 25-30 years after which their specifications may deteriorate. If those caps are involved in the power supply, they may cause the delivery of improper voltages to other boards, possibly damaging them or reducing their functionality. So most people say at least recap the power supply, which on your unit is on the main amp board. After that, most replace caps in the rest of the audio path - power amp, tone board and phono board. Again, not 100% agreement on this. There are also a couple of known problematic transistors that most routinely replace in these boards. Not sure if yours has any of them or not. Then, if one wants to go further, the signal path boards are done - tuners, etc. - but leaving all semiconductors and adjustments alone in order to not affect tuner alignment. I can tell you from having done several of these that I always hear better highs and lows after doing the audio path boards. So take this for what it's worth. Others can give you a more educated opinion.
Steve
