My pro trek solar powered watch still tells the time but other functions dont work any idea

I am thinking you need a new battery. It appears to be a battery operated watch that runs on solar power IF there is light.

How long will a Timex Solar watch last?
The solar movement functionality creates an environmentally-friendly and maintenance free timepiece that can be charged through indoor fluorescent light or outdoor sunlight. Once fully charged, the battery life can reach two months. If worn daily, there is very little chance the watch will stop.

Solar Powered Watches ' Timex Blog

Try the links. Casio has two distributors for parts.

MANUAL ' PRO TREK - Mens Watches - CASIO

https://protrek.com > asia-mea > support
WATCH MANUAL ARCHIVES. Use this page to download a copy of CASIO watch manuals in PDF. To download a PDF file, enter the four-digit (or three-digit) module ...
Missing: movement ‎' Must include: movement

Buy Parts - Casio Support Page ' Casio USA

https://www.casio.com > support > buy-parts
For end-users looking to purchase Casio watch bands and watch parts, please contact one of our Parts Distributors* below: West Coast PacParts, Inc.
Missing: prt500 ‎1376

Casio ProTreck PRT-500 Please Help - where do the springs ...

https://www.watchuseek.com > ... > Casio G-Shock
Dec 10, 2013 - Hi there! After finding my old PRT-500 in a drawer I took it to a shop to replace the battery. They messed it up, the watch displayed "open" ...
Casio PRT-500 issues/ watch to replace it - Watchuseek
Jul 11, 2008
CASIO PRT-500. Please HELP ME. - Watchuseek
Oct 10, 2006
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THe PRO-TREK watch compass is very sensitive to nearby Iron (eg. cars, fridges, steamships, artillary canons, battering rams, guillotines, etc) and anything wearable or embedded in your body. I had to calibrate mine in the middle of a baseball field.

try this link > http://www.watch-band-center.com/watchstrap-s1237h243-CASIO-Straps-Metal.html

mcdevito75 here, I see in your question, SOLAR if that means the watch is operated from the sun"s energy, you first have to get the watch going (ticking) before you can set the time, Instead of a Battery your watch has a capacitor that holds onto the sun"s energy and releases it, makeing the watch go (tick). After the watch goes, you need worry about 2 buttons, MODE & SET. Press MODE and see display Flashing, now press set to set each function, (hour, minute etc.) presss MODE after ecah function is set to move on, once all functions are set, press MODE for steady display, also if thew watch is new, look for a small piece of plastic just under the crown, remove that plastic and push crown down to start watch. Hope this helps.

Actually, "chg" means "change" in this case. Since this is a solar watch, it is not necessary to change the battery. I let my watch sit in the dark for a few months and I came back to the same screen when I dug it out of a drawer. Simply allow the solar cells to get some light to recharge. I left the watch under a lamp overnight because I needed a stopwatch in the morning, and it was charged by the time I woke up. Also, this watch has a power saver function you can turn on and off. If the watch is left in the dark for about an hour, the screen will turn off but the normal functions will continue in order to save power..

Click on my profile (escapement), then click on Tips and Tricks. There you will find link to all CASIO watch manuals.Rate me, please

As you will see from the extract from the web site, these watches are solar powered.

" Tough Solar Power

• Shock Resistant
• 200M Water Resistant
• 29 times zones (48 cities), city code display, daylight saving on/off
• 4 Daily Alarms and 1 snooze alarm
• Countdown Timer
  Measuring unit: 1 second
  Countdown range: 1 second to 60 minutes
  Other: Auto Repeat
• 1/100 second stopwatch
  Measuring capacity: 23:59’59.99”
  Measuring modes: Elapsed time, split time, 1st-2nd place times
• Auto Calendar (pre-programmed until the year 2099)
  12/24 Hour Formats
• Accuracy: +/-15 seconds per month (with no signal calibration)
• Storage Battery: CTL1025
• Battery Power Indicator
• Power Saving Function
• Approx. battery life: 6 months on full charge (without further exposure to light)
  Module 5055"

Sounds like the solar back up cell needs to be replaced. You can get it repaired for rather cheap less that $30(US). You can contact www.casiosalesandservice.com to have it serviced. 877.659.0761

Send it into repairs and they will send you an estimate on what it would cost to fix it. Give them a call at 800-706-2534 option 2.