Problem Identified. Solved temporarily.
Dear Members,
The problem is resolved and I thought i can share my observations so that it may help some other member who may encounter this same issue.
The issue of the stereo imaging was probably related to the connection at the Mute switch or the Mute switch itself.
This is what was done yesterday:
I disconnected one of the wires going to the mute switch. The disconnected wire was wrapped with an insulation tape. On this turntable, the wires to the mute switch are connected from the same terminal where the RCA s are connected. These wires appeared to be new, hence they became the primary suspect and cause for diagnosis of this problem.
I have a feeling that these wires were connected wrong and not to their respective R or L channel. I have read on various forums that the mute switch plays no role in the chain of the circuit, but one valuable tip from a forum member on vinyl engine that i should clean the mute switch and this could be the problem, did make me think about looking at this point.
Another suggestion was to check the resistance from Tonearm to RCA tip which I did and found to be identical at all four points.
Excuse my ignorance I got a reading of 023 / 024 on all 4 points.
After the above experiment, played an LP and was thrilled..... the stereo imaging has come back.
Now I plan to reverse the connections at the mute switch as an experiment to see if this maintains the imaging. In the negative, i can live without the mute switch but not without the stereo imaging
I have limited knowledge about electronics and was so glad to receive help from our form members here. This really inspired me to eliminate the possibilities one by one in order to diagnose the problem and find a solution. It would not have been possible without the suggestions of members of this form as well.
I thank all members for their valuable suggestions.
Regards
Rajendra