I'm going to add a couple of pointers with this piece of mass-produced kit that i experienced 1st hand dealing with... Background: i have been servicing gear for over 35yrs so to some extent i have 'seen it all'. Without being too rude the quality and workmanship of the product and it's final assembly is a bit to be desired... (I guess that's how costs are cut to the minimum).
The last thing OP you need to check before buttoning up your repaired unit is to 100% be certain the soldering of the two big smoother caps is REALLY GOOD. The unit i had the joy of meeting had cracked open all 4 contacts to the PCB and the owner talked of sound system working perfectly but at high volume it would suddenly
"making a noise fit to wake the dead'!... (yes unsmoothed +Vcc being feed to those chipsets just has to be a formula for disaster)...
Like the rest of the Amp, i suggest putting a bit of hot-snot glue around those big smoothers at their base so they can never wiggle on the solder connections again.
Finally when you button the thing up you need to really re-seal all the cabinet/enclosure surfaces so there will be zero chance of a whistle and hiss effects from the air being 'pumped' by the sub.
Just my 2 cents worth.