I've found a ground lug in a Kilowatt Grounded Grid amplifier... that didn't ground the grid. I found a bad solder joint that looked ok, but was intermittent,

I've found a ground lug in a Kilowatt Grounded Grid amplifier... that didn't ground the grid. I found a bad solder joint that looked ok, but was intermittent, and had been that way, in a Television built in 1948 and used for decades. Bad design and assembly goes back forever, as near as I can tell.