No Sound From Cartridge Unless Volume WAY UP

Great volume out of one cartridge; no volume (to speak of) out of other; my gear setup:
Turntable: Technics SL-1210M5G
Cartridges: AT150MLX, AT440MLa
Amp: Cambridge Audio 540R
Phono Stage: Cambridge Audio 640P MM/MC

Not sure what the difference is here. Both cartridges are MM and should play fine with the Cambridge 540R/640P combination. Combpliance (re: is fine for both. The AT440MLa plays fine and sounds great. I wanted to try the AT150MLX, as most people with the Technics SL=-1210M5G consider this a winning combo. I finally received the 150MLX the other day and spent a lot of time loading the cartridge to get it right and triple checked setup. I used a Mint Tractor to align everything. However, at my normal listening level, I get zero sound; I have to turn the volume all the way up (yes, as far as it will go) to get a decent, slightly loud (not ear-busting by any means) volume generated. I know the cartridge is fine for compliance;…could this be an Output (mv) problem? The 540R does a great job pushing a surround set-up, and volume is fine (like I mentioned) for the other cartridge. Any feedback will be greatly appreciated; I'm really stumped. Thank you very much.
Dear Bluedenmant: Maybe is wrong wired at its connector pins.

Regards and enjoy the music.
You should pull the stylus assembly out and blow on it and into the cartridge body. There might be some dust of other crude that's keeping it from making a good connection. It might just be a defective cartridge.
That's definitely not normal response for an AT150MLX, Technics SL1210, and Cambridge 640P (I have that exact chain and used it to feed line level inputs of an integrated amp as well.)

Follow Raul's and Mofimadness's advice and if those don't fix it, I guess you need to see if it's defective, given that your 440MLa worked fine.
If it's got a removable stylus - is the stylus seated all the way back into the cartridge body? If not that - check pinouts? If still nothing - borrow a ohm meter and measure the resistance (Ohms scale) between the + and - of each channel - plus probably not a bad idea to measure the resistance between all the pins relative to each other.
Are these carts being installed in exactly the same headshell? If not - take a look at the pinout on the one that works - is this identical with the pin out of the cart/headshell that doesn't work? In other words - is the red wire going to the same position in the headshell on both headshells,green to same position ,etc.
Any of this stuff purchased used or all new stuff ?
measure the resistance (Ohms scale) between the + and - of each channel

A note of caution: This is generally not a good idea as the current generated by a voltmeter for measuring resistance could fry the tiny wires inside a cartridge (at least for certain MC types).
Being my first thread on Audiogon, I want to thank each of you for your input. I'll try all the suggestions and see if they don't resolve the problem. From what I'm reading above, it's beginning to sound like a connection problem. I'll go back, retrace and check again. I used the Technics default headshell for the 440MLa, and a Zupreme (lpgear) headshell for the 150MLx, adjusting for the weight difference; if checking the connections doesn't result in anything, I'll try loading the 150MLx on the Technics headshell (lighter weight) and see if that works. Again, thank you for the suggestions...Tony (bluedenmant)
15 minutes after reading responses: Really helpful knowledge from all of you. First thing I did was check to see that the stylus was connecting properly...and it was not. It had not clicked-in properly. Ran test, volume is where it should be now. I'm a bit surprised that it would put out any sound at all (esp. through both channels) if not connecting properly, but it did. Analog is certainly a step-by-step process; I won't forget this one. Again, many thanks to each of you that responded. Tony
Glad it was an easy fix - enjoy the sound the music through your analog set-up now!