Dead Left Channel on my Kenwood CI Pre-amp

[bulgin]

Hi Guys

Knocking on The Door again as I have a spot o' trouble with a dead left channel on the phono input of above said pre-amp.

I have spent two days swopping out i/c's, trying the other inputs (which all work), changing cartridges, headshells, armwires, cleaning input jacks until they positively gleam but no go, the left channel stays deader than o'l dodo.

It looks like a kinda difficult job to lift out the board to check for a cracked/dry joint of an rca phono jack but I'll give it a go tomorrow.

Do you perhaps have any other ideas what the cause of this problem could be, please?

Thanks in advance

bulgin