I have an 8644B which had power supply issues when I purchased it as a non-working auction off at e-site. I traced it to bad connections around the connectors for the power supply. Removing the power connectors where plugs into the motherboard, cleaning good with contact cleaner, and reinstalling seem to clean that up. After that, I discovered a bad frac-n card, which I was able to find rather cheaply. It works pretty good after fixing all these issues, but I usually use the 8663A due to its crystal clean signal. Anyway, I seem to remember seeing that exact same type of thing on mine, and cleaning that molex type connector fixed it. I think HP ended up putting just a bit more current through that connector then there should be, causing problems years later. Hopefully your unit will be just as easy to fix.?
