Thanks for the additional info. I'm hoping to replace tonight a few switches and outlets that looked obviously old and nasty. I will continue troubleshooting if that does not help.

 

I only measured across switch contacts and not hot-to-neutral. Will do additional test and measurements later.

All voltages should be measured with respect to the neutral.
SG

 

If you can't get to the neutral in the switch that controls the bad outlet then plug an incandescent lamp into the "bad" outlet and measure across the switch again. Should have 120 volts with the switch OFF. This will indicate the neutral is OK from the outlet.
SG

 

If you can't get to the neutral in the switch that controls the bad outlet then plug an incandescent lamp into the "bad" outlet and measure across the switch again. Should have 120 volts with the switch OFF. This will indicate the neutral is OK from the outlet.
SG

I respectfully disagree. If there is a high resistance connection anywhere before or after the switch, the meter, will read the line voltage. The reason being, even a marginal connection, carrying very small currents, will not have a significant voltage drop.

 

I respectfully disagree.

That is correct. What's weird is the TS measured 42 volts across the switch when open. Was curious what it would read with a lamp plugged in.
SG

 

Update. Changed the crappy switch that went to 2 disconnected fluorescent lights in the bathroom. No change anywhere.

Changed the "bad" outlet that was tied to the switch above it (and changed the switch too). That outlet had two circuits feeding it. But the center tab separating 2 hot screws was still intact. Removed the tab. Nothing changed... voltages are slightly different but still in about the same range.

Found a few other outlets wired in the same way. Removed the tab. But that was a mistake. Apparently some of them outlets were wired like that instead of a wire nut to pass electricity through the chain to the next outlet. Replaced them again keeping center tab. At least restored power to where it was lost after removing the tab.

I'm kinda done with this. Gonna wait for the electrician to come out on Friday. I'm all out of ideas and I know it will be expensive.

Wonder if I can sue the house flipper...

 

Update. Changed the crappy switch that went to 2 disconnected fluorescent lights in the bathroom. No change anywhere.

Are the neutrals still connected in the disconnected fluroescent lights?

Changed the "bad" outlet that was tied to the switch above it (and changed the switch too). That outlet had two circuits feeding it. But the center tab separating 2 hot screws was still intact.

That would imply that the outlet is feeding the switch.
SG

 

Changed the "bad" outlet that was tied to the switch above it (and changed the switch too). That outlet had two circuits feeding it. But the center tab separating 2 hot screws was still intact. Removed the tab. Nothing changed... voltages are slightly different but still in about the same range.

That is how most series/chained outlets are done. when the tab is removed the next outlet in the line and all past that one stop working. Only one of your, " That outlet had two circuits feeding it" was a feed to the outlet, the other was going to the next outlet. If you don't do it this way you end up with too many wire nut connections in the circuits.

 

AC LINE on duplex outlets (outlets with two sockets) are normally wired together with the interconnecting tab.
Normally one does not break off the interconnecting tab. One would break off the tab if the two outlets are being fed from different feeds. For example, one outlet can be constantly live to power a clock radio, while the other is switched to power a bedside lamp.