It depends on the 140 version but generally the frequency releases cover from 140MHZ to 174MHz or a little lower frequency but that module according to the manufacturer gives its maximum power between 150MHz to 175MHz. In these models, the release is usually by cutting a cable that comes out and enters the front and then resets the equipment. I clarify that it is totally illegal to operate by issuing those releases outside the frequencies assigned by the competent authorities of your country. Here http://pdf.datasheetcatalog.com/datasheet/MitsubishiElectricCorporation/mXyzrvux.pdf you have the data sheet provided by the manufacturer where it says such frequency limits. -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------- In the schemes of the models that I have, you should check what is inside the red circle. The arrow indicates the part of the red LED of TX, you should check Q302, Q308, R307 if it reaches 5V and if there is presence at the time of TX, of the 8V transmission (which is what makes the red LED turn on) in The base of Q308. Check the PCB tracks or cold welds on these components that are usually the cause of these symptoms.