I owe you an apology, flip_normal.
I assumed all GuoLiLai 500W 48V power supplies have the same circuit board layout. My last post was based on this.
I was at work, away from my PS, when I last replied. I went home and took a closer look, and your PS definitely looks different, even though the topside components appear to be laid out similarly.
This morning before leaving for work, when I had good daylight, I took some closeup pictures. Today I played Hookey a bit, and labeled them like you did yours.
Topside with components; mine is labeled M1B-003, yours is M1A-002. I wonder if there is a difference beside the layout of the copper traces?
Bottomside with wires carrying mains power from one corner of the board to the other. You mentioned one of your PSs blows a circuit breaker when powered up; I would first carefully check these wires and their solder joints -- or better yet, just replace them outright like I did. If those are okay, then it might be other solder joints, or the input PFC (power factor correction) inductor (looks like a transformer), or input capacitors or MOVs might be shorted. The short would have to be big & obvious to blow circuit breakers.
I think you figured out how to boost the output voltage on your particular model of switcher PS.
Looking at your pics and following your description of changes, they look & sound correct. Be sure to check for a zener diode which limits the maximum voltage, the voltage rating on the output capacitors, and the power rating of the output bleeder resistor. Make your changes safely, so you don't burn down your house.
Here's what the sticker on the side of my PS looks like; Is yours the same?
When my PS is back together again, I can play with VR2, which Fechter thinks limits the maximum output current. I think he is correct, but I am unable to verify right now.