How to test a cartridge?

Yesterday, while listening to some LP's, I lost the entire left chanel. I swapped out the pre-amp, the phono-pre, took the step-up transformer out of the chain, changed turntables, changed interconnects, changed speaker cables, and the result remained the same (dead quiet on the left chanel).

Today I put an ohm meter to the contacts on the cartridge (it is the only one I have, so I can't swap it like the other stuff) and got equal resistance readings for both chanels.

What am I missing? This one has me stumped.

Thanks in advance, Dave.

BTW, the digital front end works fine.
I think either the preamp or the cartridge have problem.

I suggest you to connect the right phono cable(the one with sound) to the left input in your preamp(phono input) and the left to the right. If there is sound from the left but no sound from the right. Then the is a problem with the cartridge.

If there is no sound from the left and sound from the right side, then the problem is in your preamp.
Edle, though I think Consttraveler's cartridge test might cast some doubt on the cart being the problem, his swapping-out the preamp and phono preamp eliminates the preamps from being the problem. Consttraveler, since you say you swapped out all the IC's plus the TT, I will assume that there is no wire, including headshell leads, tonearm wire, etc. in common. If so, this is a stumper for sure, but I would take the additional step of hooking up the cartridge with the headshell leads reversed left for right, just to double-check on your meter-reading test, since it appears that your cart is the only common denominator.
Consttraveler, you say you changed turntables? This I find a bit confusing. Do you mean, you removed your arm plus cart and mounted it on another turntable?? Why that? Did you check your cartridge leads to the phonopreamp with your ohmmeter? Do both carry signal? If yes, do as Zaike suggests and let us know how it goes. Good luck!
Thanks for the quick responses!

Edle: I did switch the pre-amp leads which resulted in the sound moving to the left channel, and the right channel dying. That's when I hooked the ohm meter to the cart.

Detlof: I removed the cart from my Rega P-25 (thinking I might have a problem with the Regas' connection. I then installed the cart. in my Thorens TD520 / SME 3012R, that also has a brand new set of cart. leads installed in the headshell. Same result, no left channel sound, not even background noise when the volume is cranked.

After all that, I removed the cart., checked it with the ohm meter and got approximately equal resistance on both channels. I then re-installed the cart in the headshell and checked the resistance at the connections on the downstream end of the headshell. Same result, equal resistance on both channels.

Zaikesman: I am going to try swapping channel leads to the back of the cart., as you suggest. If it is the cart. I should get music on the left channel only, correct?
Correct - let us know what happens, this is truly a mystery for the time being...
OK, here is what happened.

I changed all four leads from the headshell to the cartridge, left channel & ground to right side, and right to left. I still have music from the right channel only!

BTW, I double checked all interconnects and speaker wires and every thing is connected correctly (right to right, left to left, etc.).

I'm at a loss! Anybody have a suggestion?
So it would seem the cartridge is outputting a signal from both channels, and the left channel signal is apparently getting lost somewhere later on down the chain.

Let me just reconfirm what you've tried here - At least *two* entirely and completely *different*: sets of headshell leads; tonearms and their internal tonearm wires; turntables; TT lead-out interconnects; phonostages; interstage interconnects; and control preamps - with only the cartridge (which tests fully operational) remaining the same before the power amp and it's lead-in interconnects, and with other sources such as CD playing correctly in both channels throughout all of the substitutions (thereby ruling out faults anywhere after the control preamps)? And there is no common step-up transformer, or junction box or adaptor jacks of any type in use before the phonostages?

In other words, *every single thing* in between the cartridge's pins and the interconnects going to the amp has been replaced with no changes to the left channel status, and both the cartridge and everything after the preamps' output jacks is proven to be working correctly as far as you can test? And for every one of the substitutions, there was no interruption of the right channel status that would indicate the insertion of a faulty piece of gear?

If all of the preceeding is so, then I suppose you cannot rule out the small possibility that both of your phono chains have different pieces of gear in them with the left channel out. I would go back and reinstate your normal chain of gear you were using when the problem first appeared, and then methodically go through it swapping each connection right channel for left channel one at a time in sequence and listening each time to see if the problem switches channels at the speakers, beginning with doing the headshell lead channel-swap once again, and doing it first at the cartridge end and then again at the tonearm end, and then so on down the chain toward the preamp (at each step, you can either leave the previous connection reversed for the moment if nothing changes or put it back - it shouldn't matter if the problem channel doesn't switch sides with any given connection channel-swap), and see if the dead channel still refuses to switch sides until you get to the interconnects leading out of the preamp (and if that's what happens, double-check yourself by then plugging your CD into the *same* preamp inputs you're using for the phono, just to make sure it results in sound in both channels again). But presumably, at some point along the phono chain the dead channel will have to switch sides at the speakers during this process, indicating where the fault lies. If that happens, then I would re-hook-up the other phono chain and do the same thing all over again, to see where a possible similar fault lies there.

It's a bitch, but there's got to be a rational and discoverable explanation, however unlikely, for what's going on here...otherwise, I'm going to start believing in audio-gremlins, and I might have to run out and purchase an entire Shun Mook suite in an attempt to keep them at bay! :-)

Befor I got your last response I started doing exactly what you suggested. Last night about 10 pm I found out what must have happened.

When I swapped Phono-pre's the first time I also must have swapped interconnects at the same time (lesson #1, only try one thing at a time!). Last night, I found that the left channel in the Herron Phono-pre is dead, and one of my interconnects I had on my Coph Nia (left channel of course) is dead.

As it turns out, every thing is working fine with the exception of the left channel of the Herron. Probably a tube, so I'm going to swap some tubes around (see lesson #1 above) and see what happens.

Thank you all for your help.
Aha! Mystery solved! Lesson #1 "One variable at a time", indeed...I'll bet you've just got to smile now at all the worry and effort you must have expended trying to crack a pretty unlikely double-failure. These things can nearly drive you insane second-guessing yourself when you can't seem to find any logical explanation, but eventually you always reach the point of revelation where you realize you weren't quite as methodical in your systematic analysis as you thought. Can't really blame you on this one however...glad to hear the earth still goes around the sun for another day - Happy listening!