I actually have a few trucks at work that have cb in them plus we have about 40 handheld uhf radios, been the fleet super I think I should try get more knowledge on this so Me and my crew can start maintaining our radios.
OK, thanks for the clarification.
There really isn't a lot of maintenance you can do on modern radios without really getting heavily into high end test equipment. That really is best left to the professionals.
However, there is work you can do that would at least help you narrow down the issues. Knowing if it's a radio issue, coax issue or antenna issue can help you save a lot of money and make sure you are not blindly replacing parts searching for a cure.
A couple of things I'd recommend…
The Bird 43 is a good option. I can imagine a bunch of fleet mechanics can be pretty hard on equipment, so the consumer/hobby grade stuff should be out. It won't stand up to the abuse. Fine for someone testing a radio in the garage or hobby room, not suitable for use in any sort of shop environment. As I'm sure you know, decent tools always pay for themselves. I'm willing to bet you guys are not using Harbor Freight tool sets, don't go the same route with your radio testing.
I'd say unless you guys have a really good budget, I wouldn't necessarily spend money on a brand new Bird 43. As I stated above, they are fairly simple devices and not much to go wrong. If you can find a used one at a good price, it might be a good way to go. The one I bought used looks like it went through WW2 a couple of times, but still works just fine.
If new is an option:
https://www.theantennafarm.com/catalog/bird-43-3752.html?zenid=1e75788ceed6dd54174f780dfdca0eda -choose the SO-239 (UHF)- connectors when you purchase.
This one is an option, but since it covers 25-1000MHz from 5 to 1000watts, it tends to give up a bit of accuracy. I'd still say go with the Bird 43 above.
https://www.theantennafarm.com/catalog/bird-4304a-3807.html?zenid=1e75788ceed6dd54174f780dfdca0eda
You'll need the elements (slugs) for the frequencies/power levels you use.
At minimum you'd want:
Bird 5A. 25-60MHz up to 5 watts. This will cover your CB needs well.
https://www.theantennafarm.com/catalog/bird-5a-3759.html?zenid=1e75788ceed6dd54174f780dfdca0eda
Bird 100C 100-250MHz up to 100 watts. This will cover your VHF radio.
https://www.theantennafarm.com/catalog/bird-100c-3770.html?zenid=1e75788ceed6dd54174f780dfdca0eda
Bird 5D 200-500MHz up to 5 watts. That'll cover your UHF portables.
https://www.theantennafarm.com/catalog/bird-5d-3773.html?zenid=1e75788ceed6dd54174f780dfdca0eda
I'd also recommend a 50Ω dummy load. This lets you test into a know good load:
https://www.theantennafarm.com/catalog/diamond-dl30a-5007.html Being able to transmit into a safe and known good 50Ω load can tell you if the radio is transmitting and how much power it's putting out.
A few jumper cables will be necessary:
UHF - UHF 6 foot jumper, for connecting radio to meter:
https://www.theantennafarm.com/catalog/8219-6-pl259-6651.html
I'd recommend two of these. There are some instances where you may need both of them, and they will also take some abuse, so having a spare is a good idea.
You'll also want some adapters. Your CB and Icom will have the UHF connectors on them, so everything so far will cover you. The portable radios will have a different connector on them, and you'll need an adapter to check those.
I use something similar to this:
https://www.theantennafarm.com/catalog/rfi-rfa-4024-wifi-6035.html It should cover what you need and then some, although it might be overkill. If you know exactly what flavor connector is on your portable radios, just order the one you need.
So, with that collection of stuff, it'll allow you to test SWR on the mobile installs, both CB and VHF. That can assist you in determining if the fault is with the antenna and if the antennas are tuned properly.
Using the dummy load, it will tell you if the radio is putting out RF energy. Put the dummy load on the antenna end of the cable, and it will tell you if your coax is good.
Same goes for the portables. You can hook the portable up to the Bird meter and connect the dummy load to the other side. This will tell you if the radio is transmitting. Since portable radios tend to take a lot of abuse, and the antenna connector is easily damaged, this can answer the question if that is still working.
A basic multimeter should be part of your tools too, and I'm sure it already is. Being able to see if the radio is getting power is a good step. Checking fuses. Also being able to check continuity through the coaxial cable or looking for a short circuit is a good step that a multimeter will solve.
Of course knowing how to use all this stuff is important, and that will either be trial and error, or get someone to give you some quick training.
Down the road, there might be a really good argument made for being able to install your own coaxial cable connectors. This isn't horribly difficult if you have the correct tools. Stock a crimp tool, stripper and a few connectors and you'll be good to go.