I have a mitutoyo 500-422 and how do I replace the battery

Might replace the battery?

Apparently the battery is Circuit Board mounted and is a backup memory battery.

Li (lithium) battery • The Li battery is mounted on the printed circuit board in the data processing unit "QM-Data". Do not dispose of the data processing unit by burning it. If the data processing unit is thrown into fire, the battery may leak chemicals, burst, or burn violently. Comply with government regulations regarding the disposal method.

and

• This error message indicates that the memory backup battery is low, and that if you continue to use the data processing unit "QM-Data", backup will not be performed. Save the part programs and measured data stored in the internal memory of the data processing unit to the floppy disk or to a personal computer. • Contact your supplier to replace the battery.

It also says changing the battery removes any saved data.

So if you are looking to do it yourself, look for screws to get inside.

https://www.mitutoyo.com/webfoo/wp-content/uploads/QM-DATA200_2222.pdf

..

Ebay for about 8 bucks.

Find the little battery compartment on the back. Slide it open, tap lightly against your hand to drop the battery out. Insert a correctly-rated new replacement battery in the same orientation as the original battery. Slide the cover back on. They make it about as simple as possible.

Try cleaning contact pins of U-WAVE-T cable with 91% alcohol pads
If possible replaced batteries in gauges and U-WAVE-Ts

User's Manual:
http://www.mitutoyo.co.jp/eng/support/service/manual/pdf/99MAL110B5.pdf
Quick Manual:
http://www.mitutoyo.co.jp/eng/support/service/manual/pdf/99MAL216A7.pdf

The Mitutoyo 500-115 caliper does not have an off button. It automatically shuts off after two hours of non use. Very frustrating since after just a few times of using the calipers 6+ hours of time has been used on the battery and consequently it doesn't last long. I am in the middle of adding a switched battery holder to my calipers. I have already milled a channel for the wires and tomorrow I do some soldering and two sided 3M tape to mount it to the back. The switched holder is Adafruit 12mm Coin Cell Breakout w/On-Off Switch [ADA1867]. The battery you should use is 1.55V Number 390 (Energizer). We'll see how this turns out. Sick of putting batteries in it. Go figure total cost of all of this is around $15 which includes a new 390 cell from the hardware store. That's about 5 years worth of batteries. Maybe it's the principle of it. At lease now if/when I do replace the battery, no disassembly required.

In mitutoyo digital vernier battry inserted upper portion side by display you battry cover theire is an arrow mark downward release you will find battery in side remove it and put new one battery code Sr 44 you will from marketor in mall try it

Sounds like the new battery you installed is no good. Is the display also dim? When the battery is low that is one of the results on the Mitutoyo. Do you have another battery to try in it?

The battery compartment is on the front of the instrument. The cover is round and has some symbols that resemble arrows pointing down. Slide the round cover down to access the battery.

There should be a battery cover on the back of the case that will have a small release catch on it that will open the compartment up. Mine has 2 batteries in it. Hope this helps you.