How to check an IC?

Yes, 3 to 4 ohms sounds too high, assuming that the length of the cable is not extremely long (for example, 50 feet!).

If you are confident that you did the measurement properly, and that before and after you made the measurement you checked that the meter read 0 with the probes touching each other, I would say that you have a marginal connection at one of the connectors.

Regards,
-- Al

Thanks, I'll try to re-do the RCA plugs. My soldering skills are in the developement stage yet.

BTW, what temperature on the soldering gun do you guys use for sodering RCA plugs?
I have Hakko 936 iron, and use WBT 4% silver solder.
When I used 700 F, as recommended by Chris Venhaus, I found it to be insufficient for this particaular job, and had to use my old RadioShack iron, which, I guess is hotter, and that did the job.

What size tip? I find 700 degrees and a fatter tip works very well for connectors.

I don't know what size it is, but it's small. Much smaller, than RS one.