I have a set of LE175's in jbl Apollo cabinets from about 1967. One of them plays weak and reads a low on the ohms, around 3 from what I recall, the other was around 7. The are marked 8 ohm but have the red dot instead of green, so I figure they are 16. The le175 calls for a D16R2410. I have a NOS D16R2420 diaphragm that I have tried with some improvement but am not happy with it. I've swapped the horns between cabinets to rule out cross overs and other issues. Any thougths?