Inspecting a newly acquired HP 2392A I found out the chassis was prone to whiskering all over the chassis.
Whiskers are small metal hairs growing from pure metal (zinc or tin) and can when they connect to a power line create a shortage and electric arc damaging the electronics. Made some pictures and placed them in: https://www.flickr.com/photos/hp-fix/41897770664/in/dateposted-public/ It's best to remove them by using scotch brite or fine sanding paper, after that paint or coat the chassis with a clear paint or other nonconducting paint. More info about whiskering can be found at: https://nepp.nasa.gov/whisker/ https://en.wikipedia.org/wiki/Whisker_%28metallurgy%29 -Rik
