Blake, as far as testing a 5101... or your 6821s. If you'll be repairing a good amount of machines, you'll want to grab the Neoloch Inquisitor with SRAM & PIA blades. http://www.neoloch.com/products/Inquisitor.php If you can solder, you can buy it as DIY kits. Takes a bit of time to put together, but well worth it with being able to verify if SRAM or PIA ICs are good/bad.