May 25, 2023
One of devices familiar to all radio amateurs: a walkie-talkie, which is a means of two-way mobile communication. Some people call it a cordless phone, but in mouth of weak people, more common name is called a "handset".
An inexpensive and highly functional walkie-talkie will also have some malfunctions during use. In face of these faults, how do we determine point of failure and fix it?
1. Inspect appearance and eliminate mechanical damage
When you receive a defective walkie-talkie, first check for signs of damage on outside, such as broken antenna, damaged display screen, cracked circuit board, damaged case, damaged buttons, knobs, switches, etc., in practice whole machine can be brought back to normal by eliminating mechanical damage.
2. Look at screen to determine location of problem
When you receive a defective walkie-talkie, you must identify defective part of walkie-talkie by looking at display. For example, there is no button indication, programming indication does not change, there is no indication, etc. Based on these observations, one can preliminarily judge location of malfunction.
3. Look at function
When you receive machine by viewing it on display, you must reset operation according to correct method, and errors like blocking and crashing can be eliminated.
4. Look at current to assess failure of receiving and transmitting circuits
To test walkie-talkie, if you use a 0-2A ammeter in series with power circuit, you can judge whether receiving and transmitting circuits are normal by looking at current. Turn on power supply and receiving status shows that current is about 3 -10 mA.
When squelch is disabled, if noise is currently normal and current increases to about 40 mA, it can basically confirm that reception is normal. Press button, according to power setting, current should be about 550mA. If current reading is very small, such as less than 100mA, check that transmitting part of walkie-talkie or power amplifier is not working.
5. Check PCB
When walkie-talkie is turned on, first check for any damaged components on circuit board, such as broken components, burnt wires, exposed solder joints, etc. After inspecting these components, entire machine can often be quickly restored to working order.
6. Efficient use of various maintenance tools
Various inspection tools are inspector's right hand. If you can use appropriate tools flexibly, it will be of great help to your inspection. In some cases, some faults cannot be repaired. This requires that each repairer be proficient in using a variety of maintenance tools when repairing radios.
Interphones are different from other household appliances, and maintenance methods are also different. Especially when overhauling intercoms without circuit diagrams, you must understand correct maintenance methods.
