Turntable problem..setup

during the last week +, purchased a dual 1219 turntable. in playing the table...i'm only able to get a mono signal..but when on stereo...music is only out of one channel. in re-attaching headshell (several times)..the signal becomes intermittant. suspect it is the headshell contacts. upon inspection...they seem worn. also...the table interconnects...when 'tapping them' seem to pick up the sound of the tapping. QUESTION IS: should i replace with a new shielded pair. thanks for your thoughts
The veritable 1219 had some problems, the two you mention being the most common. The contacts that mate between the headshell and the arm were pins that went into a plastic collar. If the headshell was bumped, the jolt would bend or push in slightly these pins, causing intermittent contact. Between that and oxidation on the pins themselves made for an insecure connection. This was true even when the 1219 was new. Another problem was the oxidation of the bearings of the pivot unit. This oxidation, along with maladjustment, sometimes caused the bearings to exhibit capacitance, and by moving the tonearm you could actually "tune-in" local radio stations. This may be the cause of the "noise" you hear while tapping, and it is doubtful that replacing the internal interconnect will solve this problem, one can imagine the damage that could occur by ripping this out! Use and adjustment of the pivots (was one pivot piano-wire?) should return everything as it was. The adjustment most likely to be "off" is the antiskate control, it was never good and you should get a blank (grooveless) record to adjust it properly.