does anyone here know how to repair digital fishing scales I have 2 sets that register 1.25 pounds with a 4 pound diving weight hooked on it. can anyone tell me how to repair it?

Buy new scales. 

you might be able to calibrate it by putting the weight on it and then hitting the power button or if it has a zero button on it,I'm not saying it will work but worth a try

Go figure, I'm having hard times to get my scale registering more than 15 ounces.  Rough Spring for me...

Bad battery(ies) could be causing faulty reading.

   Most likely, what is used to calibrate a scale is the Poteniometer, or stroke pot.   you'll have to open the scale up.   its gonna be a very fine, tiny screw, most likely, it will have loctite sealing it so vibration couldn't cause it to come out of cal.

  By turning it CW or CCW and pulling on the hook gently prior to rotating it, you see,

    it should adjust up and down while turning the tiny jewelers screw, if it don't, its bad.

  the other is to take a resistance reading of the pot with meter.

   Try new batteries first,  The Berkley 50lb model using two watch batteries the size of Quarters unless they have changed batteries in the past years.

 

    Don't recall my Xtool scale size of batteries.

 

I'm having the same problem...My 5 lb fish keep weighing 2.3?!?! 

This is the exact reason why i tend to shy away from digital scales. Doesn't seem to be worth the trouble for me.

Some scales have default numbers that will read the same, this number could be troubleshooting code that means something to a factory tech.  it could mean low battery.  All digital scales at the hospital will give err code telling me what to check.   Improper levelling, calibration out of date, unit battery low, memory loss.

   All done by digital numbered codes.

   Try looking for a 800 number or email and ask the company whats up?