Technics SL1400 has more audio on left channel


Hello,
I have been experiencing an issue with my Technics Sl1400 recently where more audio is coming from the left channel than from the right channel. I am running a Shure V15 Type IV cartridge with a JICO SAS VN45HE. This cartridge has been on the turntable since the 70s, and I was wondering if perhaps it is the issue.

Ruling out groove wear, I have played the same record on my girlfriend’s turntable (Marantz 6025 that serves as our living room deck) and haven’t experienced the same issue.

Do I need to upgrade the wiring on the tonearm? Do I need a new cartridge, and does anyone have any recommendations as to what a good replacement would be? Do I need to somehow restore the cartridge I already have?

Thank you
Preview420jjjazz666
An easy check would be to take the Shure/headshell from the Technics and install it on the Marantz (I assume it’s arm has a removable headshell) and see if the issue is the same. At least that would narrow the problem to the Shure/Jico, or not.
An easy check would be to take the Shure/headshell from the Technics and install it on the Marantz (I assume it’s arm has a removable headshell) and see if the issue is the same. At least that would narrow the problem to the Shure/Jico, or not.

So we switched the headshell/cart over to the Marantz and did not experience this imbalance of channels. Afterwards, I moved the headshell/cart back over to my TT to compare. She could not hear what I was talking about until I played a song off an album I have on both vinyl and CD in a back to back comparison. After this, I tried switching the turntable's L and R RCAs on the amp, and the quiet side was still quiet, just coming out of a different speaker. At this point, I'm thinking its either the wires in my tonearm, or the RCA cables on my TT.
On the Technics rig, is it hooked up to a pre and amp? Or an Integrated amp/receiver? Do you have balance controls? Do you have a digital source connected to that 'amp'? Is it happening when playing digital format? 

Just trying to figure out if it is the table or something else 'behind' the table, including cables.
Did you really mention that the cartridge has been in use for more than 40 years? If I understood that correctly, then obviously there can be a problem with the cartridge, and when you retire it, it should receive full military honors for having worked for so long. It what you are experiencing of course cannot be caused by the turntable itself. It has to be the cartridge, the wires, or the phono stage.Or, just buy a replacement stylus assembly for your cartridge, and report back.
He already installed that cart on another table, and said the issue does not occur. So the cart/stylus does not seem to be the problem.