Hi, i have 3 different ph pens ( with no manual) all cheap.. 1 yellow/ another green one and a red EZ9908 4 in 1 (the best one)
I have tried calibrating these and they all jump to a different number after holding the CAL button. ( i hopd one in buffer 4.0 and it calibrates to 6.86 automatically after i release the button)
I have no idea how to factory reset any if these and YouTube has drawn blanks.
2 of them were relatively accurate before this messed up calibration (1 is toast) but now it thinks that the buffer 4 solution is actually 6.86 .
Is there any way to manually calibrate these? It seems a bit stupid that its automatic but doesn't work.
Thanks for any info ( i also don't see any screwdriver slot...there is a hole... but nothing behind it...)
I have tried calibrating these and they all jump to a different number after holding the CAL button. ( i hopd one in buffer 4.0 and it calibrates to 6.86 automatically after i release the button)
I have no idea how to factory reset any if these and YouTube has drawn blanks.
2 of them were relatively accurate before this messed up calibration (1 is toast) but now it thinks that the buffer 4 solution is actually 6.86 .
Is there any way to manually calibrate these? It seems a bit stupid that its automatic but doesn't work.
Thanks for any info ( i also don't see any screwdriver slot...there is a hole... but nothing behind it...)