I'm not sure what your picture is showing. Care to expand on this. It looks like the arrow is pointing at the tab bridging both screws on the hot side of the receptacle.

? plugging into the device magically breaks the tab?

I would assume a lose hot on the breaker or neutral on the bar and the load is enough to break contact.

Ron N found a burnt hot wire along with a melted tab for a switched outlet that has no switching it just got so hot it burnt the tab also

a switched outlet that has no switching

Huh? That seems like a contradiction. It's like saying that you have a wet towel that isn't wet. Then it's just a towel.

I don't really understand your explanation. I'd appreciate it if you elaborated because you got my curiosity going.

• 
  Testing for presence of live AC voltage aka

• (Plug any device into a string of general purpose 120/volt 15/amp outlets from a dedicated circuit breaker and the electrical power is lost to all the other outlets on the same string? Unplug the device and the power is restored to every outlet on the string? This happens to every outlet on the string not just one no matter where you plug or unplug any device. Hum wonder what the heck is going on here?)

• discovered burnt wire operating on 1 outlet that was back stabbed burnt off it also had a antique hanging light plugged into a outlet in a clothes closet with brittle cracked lamp cord wire and still in operation? hum the plot thickens. Back stabbed devices (outlets & switches) are a weak link in connection virus tapped true series circuit, along with mixing outlets and lighting on the same circuit breakers. AC electrical power 200 amp main breaker 120 240 volt single phase from utility grid will always take the least resistance to ground thru rod or rods if properly grounded.

• Older ungrounded residential wiring that needs upgrading is usually beyond repair and is a candidate for a true series circuit pigged tailed according folded grounded upgrade for a new wiring harness and devices to local, current codes and standards and inspections.

Well that just seemed like a bunch of random words and phrases lumped together into a post that didn't clear anything up. Add a random image and totally unnecessary bullets and it just adds to the confusion. :)

The bullets were used as a cross reference for the client's issue and to outline course of action found and short term remedy that was taken to re-energise the circuit breaker and string of outlets. So in short a bad original outlet that was backstabbed wired had 1 wire burnt off and barely touching for contact using the above non contact voltage tester. If further confusion exist contact me for clarification

And a true series circuit according folded outlet termination looks like this

an extra white and black wire are added to form a tap off a trunk line aka the circuit breaker that is operating the string of outlets and devices. Even if the outlet goes bad from age and useage it will not knock down stream power off to the other outlets on the same string. Only in a dead short to ground will the electrical power be lost.

So the problem was just a loose/burnt connection at a backstabbed device? Any time a load was applied, the loose connection failed.

What was with the comment about an antique light? Did that have anything to do with the story or was it just another unrelated potential problem that you discovered?

You also mentioned a melted tab on a receptacle. I'd love to see a picture of that. Was that on a different receptacle than the backstabbed one?

the antique light had brittle lamp cord wiring that was shorting out in a clothes closet

the other bad outlet on the same circuit was a switched outlet there were a total

3 different problems all on the same circuit breaker