How to reset the Polar RS800cx (and change display contrast)

It was kind of ominous to read in the manual that the watch had a function for resetting the watch. Does it really need that? Is it just an extra precaution?
Is is also easy to exchange battery on the RS800cx.

I prefer a gadget with lots of useful functions, but which may need a reset once in a while, over another gadget that is 100% stable, but miss all those nice functions.

I never shut down my PC and only rarely reset it, and I have notice that the USB IR adapter that is used to transfer data to and from the watch, works a little less good each time I use it, since last reset. There is also always a chance to get the IR adapter out of position during a transfer. I think a combination of those two things happened when I was transferring a new planned training to the watch. It took a much longer time than usual.

When I started the exercise, the training zone alarm started sounding at a way to low HR. Afterwards when trying to transfer the session to the PC, there were some extra phantom sessions in the watch memory also. The training session memory and the planning memory looked pretty garbled. I immediately set this into relation with the problem transferring the planned session. I can imagine that missing data or bad data can cause all sorts of problems, if you allow that to happen. I managed to get out my training sessions, so I didn't loose any training data. I was able erase all training data in the watch, but I never managed to clean the planned training data. It was still pretty garbled. Then I recalled the reset function. Here is the description of it from the FAQ:

"Reset the training computer by pressing all the buttons simultaneously for two seconds until the display fills with digits. Press any button and set the time and date in Basic Settings after the reset. All other settings are saved. Skip the rest of the settings by pressing and holding STOP."

Holding down the 4 buttons (excluding the start/stop button) surely reset the watch. I guess that during the reset, the watch did a check of the memory and found out that it was garbled and decided to do a full reset. The result was that I lost all settings on the watch. Most settings can be easily set from the PC software, Protrainer 5, so this is not a problem, but also the LCD display contrast setting were reset. This made the display much more unreadable. If you have never adjusted the contrast on a black/white LCD display, it is hard to explain what is is. If it is too strong, the "off" state or "white", gets too dark compared to the surroundings, the "on" state or "dark" also gets darker and thus more clear. It has to be balanced to the rest of the display background for maximum readability.

Nowhere in the manual or FAQ did I found where to change this setting. Luckily, someone posted a description on the Polar forum after having been in contact with Polar customer support. I will copy that here. The key is that you get the watch into the internal test mode, which allows you to change this setting.

- Press and hold all four buttons to reset the watch.
- Press Stop x1 immediately followed by Up x1 to get into the Monitor screen.
- Press Up x1 to get to the Internal test screen.
- Press Start to get the sub menus.
- Press Up x3 to get to the LCD Adj. menu. You will have a number here for the current setting (mine was 5).
- Press and hold Start and then press Up and/or Down until you have the contrast you want (selectable values are 0 to 15).
- Press Stop x4 to get to the basic settings dialog.
- Press and hold Stop x1 to exit from the basic settings dialog.