Okay... I think I am having trouble following. Also there might be a bit of confusion around resistance (DC) and impedance (AC). When you read the resistance across the loudspeaker terminals it has very little to do with the nominal impedance of the speakers (this is even true if you measure across the driver itself). You have a high pass filter on both the mid (12µF) and the tweeter (4.2µF) so if everything is working correctly you should get an open circuit when you attempt to measure resistance across the loudspeaker posts with everything connected.
I’ll tell you what I think I’ve understood and you put me right if I’ve misunderstood:
1) Original test with everything assembled showed 0Ω resistance across the MF/HF +/- terminals on the back of the speaker.
2) Those terminals connect directly to IP+ and IP- on the crossover PCB.
3) With the crossover disconnected the DC resistance between IP+ and IP- was open circuit.
If points 1-3 are correct and you’ve put it back together and measured 0Ω across the loudspeaker terminals then there’s a short somewhere between the terminals and where the wires connect to IP+ and IP-.
4) With everything disconnected from the crossover you measured the resistance across the copper you have marked M+ and M- and got 0Ω.
5) According to the schematic M+ and M- should be connected (at DC) via 2.5µH inductor (of negligible DC resistance) and a 2.2Ω resistor.
6) On your most recent test you measured 2.7Ω.
If point 4 was true then you’d most certainly have overloaded your amp and would have got no sound from the driver... however the most recent measurement shows no such problem.
I’ll tell you what I think I’ve understood and you put me right if I’ve misunderstood:
1) Original test with everything assembled showed 0Ω resistance across the MF/HF +/- terminals on the back of the speaker.
2) Those terminals connect directly to IP+ and IP- on the crossover PCB.
3) With the crossover disconnected the DC resistance between IP+ and IP- was open circuit.
If points 1-3 are correct and you’ve put it back together and measured 0Ω across the loudspeaker terminals then there’s a short somewhere between the terminals and where the wires connect to IP+ and IP-.
4) With everything disconnected from the crossover you measured the resistance across the copper you have marked M+ and M- and got 0Ω.
5) According to the schematic M+ and M- should be connected (at DC) via 2.5µH inductor (of negligible DC resistance) and a 2.2Ω resistor.
6) On your most recent test you measured 2.7Ω.
If point 4 was true then you’d most certainly have overloaded your amp and would have got no sound from the driver... however the most recent measurement shows no such problem.