The ear phone jack can wear out, I found a replacement
I use my Grace Digital Mondo with ear phones very often, and it finally stopped working, in that it would cut the speaker off when plugged in, but one day it did not restore the speaker when I unplugged it.
After taking the Mondo apart, and separating the two boards, the one with the display has the ear phone jack. It can be easily taken out by anyone with good soldering skills. I used a hot air tool that I often use on surface mount parts, but you can easily solder suck the pins to remove the old jack.
The replacement part that fit like a glove, came from Digikey. With the help of one of their parts locators, I measured the parts pin spacing and general description, and the part I got fit like a glove. Part # CPI-3525NG-ND
This part will not have gren on the neck, but it will do everything the old part did, and fit perfectly in the board. My mondo is back in service. The part cost under a dollar.
Is this a good question?