I seem to accumulate routers that have been replaced for one reason or another and would like to try and isolate the power supply by using a known good one. Lots of different values but within a reasonably small range of say >12V and >2A. In a couple of the router I believe their power supplies were on the mark but unstable so simply measuring them wasn't enough. A known good one will do the trick but with the price range available I'm looking for advice as to how much to spend to get a clean, accurate, stable output. Ideas?