Originally Posted by jmbach
I bought a LiteON Laptop Charger AC Adapter Power Supply PA-1041-71 12V 3.33A 40W for my Roamio Basic. Works well. The thought in this is that there would be increased power draw from the larger drives and the units power adapter may not be able to provide additional power needed causing system instability. There is no definitive proof of this only that some people experience some problems when they upgraded that went away with a power supply that can provide more power.
Just wanted to provide a data point for those interested in upgrading their Hard Drives.
I just installed a 5TB WD Green WD50EZRX IntelliPower drive in a Roamio Basic (and disabled the idle timer with WDIDLE3), and all was great for 24 hours, after which I had all the front panel lights flashing and the TiVo was stuck at the start up screen.
I had previously purchased a Woot OTA for spare parts and swapped the power brick, which immediately fixed the issue.
I've since ordered the LiteON power brick from Amazon as I'm certain the 2A OEM brick isn't up to the task.
Edit: Jan 31, 2016 - The 3.3 amp LiteON power brick completely fixed the issue...a $25 dollar fix that is working perfectly (and the barrel plug fit the TiVo very well)