Marantz CD-57 focus error fix, anyone?

I have an old CD-57 that displays "disc" whatever I do. There is a Youtube video that shows that putting a 47K resistor across R112 increases the error tolerance and then the player works. Does anyone know if this is OK to try?
And does this mean I should try twiddling the pot that sets the focus on the laser? Or does the resistor stay there as a permanent fix?

P.S. I am not very technical.....

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Marantz CD-57 focus error fix, anyone?