Topping TP-60 - help with diagnosing fault

[achinz]

The Topping TP-60 from eBay (e.g. but not the actual seller: http://www.ebay.ca/itm/Topping-TP-60-TA2022-T-Amp-2x-80W-Tripath-Stereo-Amplifier-TP60-HiFi-/200824559637) arrived with a fault demonstrated through moving the volume knob:

The volume knob is minimum at the 6 o'clock position - setting it higher than the 7 o'clock position, only the left channel works.
But when I turn the volume knob down just before the minimum 6 o'clock position, the right channel sounds very loudly (like the maximum) but now the left channel has no sound!
There is a crackling noise at that position turning it up or down.

I would greatly appreciate any help with diagnosing whether this is simply a faulty pot or something more complex in which case I would have to cut my losses with a return. TIA.

I hope this pic shows the issue a bit better:

[nigelwright7557]

I would start by cleaning or replacing the pot.

[achinz]

Thanks for the tip, nigelwright7557.

How would one clean what looks like a closed unit?

And as I'm not too experienced, I would need some help to replace this type of pot as I can't see the usual pair of three terminals for soldering the input wires in the more conventional pot: see photo below

[achinz]

Anyone else, please? - I guess the connections to this pot would be on the solder side of the circuit board and it would be just a case of removing the extant pot before replacing it with the new pot and following the same soldering points?

[nigelwright7557]

Contact cleaner usually comes with a straw that can be bent underneath the pot to squirt cleaner inside the pot.

You should be able to find a replacement with the same or similar pin outs.

[achinz]

Thanks again, nigelwright7557 !

[wolf_teeth]

Contact cleaner can actually make pots go bad faster. Please use Deoxit Faderlube.
Wolf