I never enjoy being the bearer of bad news, but I would absolutely not put an ohmmeter across a phono cartridge, or across a cable that is connected to a phono cartridge, especially a low output moving coil. The meter measures resistance by measuring how much current flows through whatever it is connected to, in response to a voltage it applies through its own internal resistance. That current will be very small in relation to the current-carrying capabilities of most devices or circuits that might be measured, but I see no grounds for confidence that it won't be large enough to cause damage to a lomc.
Regards,
-- Al
Is there any difference between a MM cart and a MC cart that would cause a complete circuit on an MC and not on an MM?Since there are far fewer turns in the coils of a lomc compared to a mm, the resistance will be much less in a lomc. As a very rough ballpark guess, perhaps a few ohms in the case of the lomc, and many hundreds of ohms or more in the case of a mm. Depending on the resolution of your meter, and the resistance scale you are using, the resistance of the lomc may be low enough to appear to be a short even though it is not.
Regards,
-- Al