Replace batttery in omron heart rate monitor chest strap

Maybe you can find a replacemente. Do a google search for terms
Heart rate Monitor, the make, model and PARTS

If can't find, do a search for Manufacturer's website and try to get information from some "Contact Us" option. Some even have a phone number.

A shot in the dark:

Accessories Polar USA

Polar Transmitters Straps and Heart Bras

heart rate monitor parts Google Search

Elastic Strap for Heart Rate Monitor Garmin

Try to humidify contact area on chest strap(each side front). Also batterie weak in strap?

Look in my tips and tricks page for the most common issues regarding Heart Rate transmission, if none of these fix it, then you "may" have an issue with the equipment itself. Generally the most common issues area:

Strap not on correctly (too loose, too low, upside down, not enough wetness to conduct)
Environmental factors (signal interference, etc)

http://www.omronhealthcare.com/media/uploads/hr-100c-instruction-manual.pdf

Here is the link to the owners manual.

You can find them on amazon, here: Finally charging for our multi device world. Have a nice day

How old is the unit? Make sure you are wetting the electrodes on the strap and it is snug around your body and in contact with skin just below your chest if female under your sports bra. If that doesn't work the battery in your strap may not be good.

It could be the battery on the strap is not good. However just to be sure make sure you are wetting the strap and it is around chest, front should sit right about on the bottom of pectoral or chest, if you are female make sure it is under your sports bra the bra band will be over it. I would start warming up then hit the start button it should work.

This link takes you to customer service and troubleshooting...I hope this helps.

http://www.omronhealthcare.com/product/1131-187-fitness-diagnostics-pocket-pedometer-hj-112

I' advise to start with battery check. If the battery is ok, then you will need a professional to find the cause of malfunction.

A HRM is a training tool that helps you do cardiovascular (CV) training correctly, neither too hard, nor too easy. It’s almost like having a personal coach on your wrist! Every HRM comes in two parts: 1. An elasticated chest strap which contains a pair of sensors that detect and transmit your heart rate. 2. A wrist worn receiver that receives the signal from the chest strap and displays your heart rate. The receiver may also have additional functions and display other information depending upon the HRM model chosen. Both the chest strap and receiver are battery operated.