I could be wrong, but I swear by that some of the 7040's we had, had proprietary PSU connections. Heck, they even use a proprietary one for their liquid coolers as well.
A well, during what you said as a time where most capacitors had that problem: I am not 100% sure and I apologize if I am spreading misinformation, but I also do not remember having issue with any of the offices HP machines ever having said issue while our dells did. Could be coincidence, I am not sure. I just never liked dealing with dell. Things may be different now, but I don't know, haven't had to use their services in at least a couple years now.
But I am interested in their XPS machines and or Alienware builds that are heavily discounted. Those from what I see are rather solid machines.