Can you tell whats going wrong from this photo?

[Ward]

Printing with the printer shown in my Avatar.

Approximately 1,700 hours on the printer
This is a 5 hour print.
PLA
3 Processes......Process 1 = 0 - .3mm Process 2 = .3mm - 12mm Process 3 = 12mm to end of print
Max movement speed 2700mm / min.
Temp 190C /Bed 60C

The print starts out fine. About 50-75% through the print (or approximately 3-4 hours into the print....it starts getting little "lint balls" of filament.
That progresses until it's just a total mess.

I completely disassembled the extruder hot end, thoroughly cleaned all the gears and the nozzle and checked it. Installed a new teflon guide tube. Reassembled. Flowed like a champ immediately after reassembly. I thought I was good to go.

However after starting a new print, exact same same thing.

Here's one clue......when the problem starts...if I end the build and if I immediately go to "LOAD Filament"....the filament does not come out properly. It's as though it's clogged again? Very little filament comes out.
This is obviously what's causing the print failure...but what's causing this apparent clogging?

My guesses......
1). Power supply is dropping power to the nozzle heater.
2). Hot end heating element is going bad.
3). Stepper motor for hot end is going bad

PrintProblem.jpg