Mike, not hard at all, If the amp is working and you just want to refurbish it.
You get a really good soldering station like this one https://www.all-spec.com/Product/WE1010NA-12200?gclid=CjwKCAjwn6GGBhADEiwAruUcKirkb0cFkp9-ph51XKhe_3...
You need a powerful iron to do a good job without burning devices. The key to good soldering is speed. Get a cheap kit for practice.
You need angle cutters and needle nose pliers.
Blast the amp off with CRC electronics cleaner to get it spotless before you get started.
Then it is just a matter of replacing parts with like parts. You can get parts from Digikey and if you want really expensive audiophile parts I use this company in the UK https://www.hificollective.co.uk/
You get a really good soldering station like this one https://www.all-spec.com/Product/WE1010NA-12200?gclid=CjwKCAjwn6GGBhADEiwAruUcKirkb0cFkp9-ph51XKhe_3...
You need a powerful iron to do a good job without burning devices. The key to good soldering is speed. Get a cheap kit for practice.
You need angle cutters and needle nose pliers.
Blast the amp off with CRC electronics cleaner to get it spotless before you get started.
Then it is just a matter of replacing parts with like parts. You can get parts from Digikey and if you want really expensive audiophile parts I use this company in the UK https://www.hificollective.co.uk/