The NAD 3020A is the second generation of the acclaimed 3020 integrated amplifier. The Orion Blue Book indicates this model sold from '82 to '84 which agrees with the date codes on the 52 capacitors that were replaced. Here are the gutty works:
Build quality is uneven. The front panel is plastic and prone to damage. Four small screws attach it to the chassis (two are seen above) and bumps to the corners crack the very thin plastic at the screw holes. The chassis itself is a bit flimsy and is built with 3 rails, two of which are visible at the ends. The third runs underneath the middle of the unit and is secured by 4 screws, two of which are visible above between the output transistor pairs and just north of the 4 main filter caps. The middle rail must be removed to access the caps. Despite some cheesiness in the overall build quality the solder work was decent and the traces were stout enough to stay put during desoldering.
There was no indication of prior work on this unit, and the amp was functional although a bit muzzy sounding with the usual pot grunge evident. All capacitors were replaced with Panasonic FCs with the exception of a pair of small, low voltage 1000 mfd caps adjacent to the main filters. My higher voltage FCs were too large to fit so lower voltage Sanyos were used. The 4 main power supply caps were modestly upgraded from 2200 mfd to 3300 mfd. Pots and switches were cleaned with Deoxit Gold and Blue Stuff as appropriate.
The results of the refurb were very positive. This is a great sounding amplifier with excellent bang for the buck. Despite the 20 watts per side it rocked the test bench Boston A40s with 'Enter Sandman' and barely lit the 5 watt LED on the display. One last pic for posterity: