[CLOSED] DJM-400 Fault. 1 channel (intermittently loosing Bass).

Hi there, I have an Issue with a DJM-400, that I bought 2nd hand.

The Left hand Channel's Bass control seems to 'waver' to -Db, in the middle of a set.. Its NOT a Uniform fault, but more of an intermittant one..But recently it has been doing it ALL the time. So, I swapped the Base 'V.R's (pots) for the Treble ones (Both Channels) due to them not 'Snapping' when put back into the middle position... The Repair went outstandingly well... APART from the fact it Didnt cure the Original problem!!

Its as if the potential of the Left hand Channels VR, all of a sudden goes to -Db, without anyone input from me!!

Im an AV tech, So I have tried the usual suspects, Diff leads, Swapping over CDJ's, checking the Output selectors are in correct positions & Checked 2 see if the fault persisted thru the headphones, (which it does)!!

So Im wondering If this is a common fault with these units, and would you know where I could get a Schematic diagram, or if anyone could point me in the rite direction of what may be at fault?!

Thank you in Advance, & Regards,a very frustrated DJ!

A~BT