need help troubleshooting

here is my situation.just bought a turntable,hooked it up to my pre which is a modulus 3a.i only had sound out of my left speaker but very faint.heard quite a bit of feedback out of the right speaker when i touched the tonearm and i could hear music playing out of my cd player even when the pre was set to phono.i then tried alternating tubes,switching linestage for the tubes that were in the phono positions,situation remained unchanged.both speakers run when i play cd's but now with a lot of distortion when they had previously been fine.flip flopped the phono cables but that didn't help.the tt was used but i listened to it in the store,however not with the pre-amp.any help would be appreciated.
the only thing different about the unit is the phono cable.i have a multimeter,how would i go about checking the integrity of the cable? i just tried unhooking the phono cable from the pre but get noticeable distortion from my left speaker only when i play a cd.cheers.

I'm not sure I'm following your point about cd distortion, but it sounds like it could be a problem in your selector switch as suggested by Dweller. If moving it back and forth has an effect, you may want to go further and buy some selector switch cleaning solution and give it a good spray. In my limited experience, selector switches are as problematic as are IC's with the kind of symtoms you describe.

As for checking continuity with your multi-meter: Set your multi-meter in "continuity mode" or "buzzer" (depend on your meter but they'll call it comething like that. Then test each lead for continuity and shorts. For continuity, you touch the meter probes to each end of the cable. If it's good, the meter will buzz, (if not, no buzz). For shorts, touch one probe to one + end, one probe to the ground sleeve. If there's a short the meter will buzz, (if not, no buzz).

Of course a quicker and easier way to eliminate the interconnect as the problem is to try another interconnect.
i am thinking it is a problem with my left channel in the pre-amp.whenever i move the volume knob i get loud distortion from the left speaker,above what is allready there.this unit has the stepped attenuators.would anything be evident if i were to open it up? cheers.
to mr dicobrazil, if you want to check the integrity of your phono cable get your tester in continuity, disconect the four leas from the cartridgg, now take the other end of the cabla riht ch rca red the center of it should show continuitty with the red at the cart.end and the ground with the green, at the left channel rca the cente goes to white and ground continuity with the blue, remember to clean the conectors what you get out of the cartridge are mili or micro volts. hope i help you carioca
thanks for your guidance on how to check my cables.doesn't appear to be a problem with ic's or the grounds of the phono cable.
done some more work here.alternated speakers,switched my mono block amps around,but the distortion remains in the left channel.just wiggling the left volume control causes major distortion and pops.emailed audible illusions,see what they think it might be.cheers