Pocket jewelry scale - Errors, overestimation of the measurement

Hello. I have a problem with my pocket weight. It is a scale without the company name (?). Its accuracy is 0.01 g, and the maximum measurement is 200 g. Until now, it worked normally, but after a long time of non-use, when I turn it on, Err 1 appears on the display, lights up for a few seconds, then UnSE is displayed (also a few seconds) and the scale is ready for operation. However, the display does not show 0.00 g, but 0.05 g (or more), and it grows up to 0.5 g all the time, and the pan is empty all the time, with no load. When I weigh something, the measurement is overstated by an average of 20% - 30%. After calibration, the scale is operational until I turn it off. After restarting, the situation repeats itself.
If anyone knows what the reason is, or how to deal with it, please give me an instruction. Below I enclose the balance sheet. Thanks in advance and best regards

Maybe you need to replace the batteries?

Not. It's not the battery's fault. I tried a few new pieces.

Can anyone help ??

I will write how these scales are calibrated. Depending on what we have, I have MH-100, range up to 100 grams, accuracy 0.01 grams (look as shown in the attached picture). In my case, I needed a 100 gram weight, borrowed from a pharmacy . Turn on with the "on" button, when it calibrates automatically and the display shows zeros press the "UNITS" button and hold it pressed for 3 seconds release the button will appear on the display "CAL" and some numbers will disappear, no matter, press once again "UNITS", this time shortly and a pulsating "100.00" will be shown, we put a 100 gram weight, after a while the scale will calibrate and show us the weight of the weight. My 10-cent coin weighs as much as 2.54 grams (weighed in a pharmacy). For weights in the 200 gram range, you will probably need a 200 gram weight. I like this Chinese poverty again
"caper"

Yes, everything is correct, the author of the thread probably calibrates correctly, and calibrates well, too. The problem is when I turn it off and on again, err 1 again and you have to calibrate again. Is there any combination after calibration so that the scale forgets the settings?
My weight is identical to 500g.
- I turn on the weight
- he presses and I hold UNITS until it starts blinking
- press UNITS once again
- as shown by the flashing 200g (we give the weighed 200g on a different weight)
- after 3 seconds it is calibrated and works correctly
- and what now ????? because if I turn off it is the same fun again.

Found a service code to scale the MH-100 and 200 series scales to higher masses. If someone wants to weigh a mass of up to 0.5 kg with an accuracy of 0.01 g, you can use this combination: