I was able to borrow a power supply for a M/A-COM MASTR III radio from a neighboring City’s radio shop.
Local agency shops can be an outstanding resource. It's good to make friends with them. Take them coffee and donuts periodically and you'll get looked after.
I was at our local county shop yesterday borrowing a programming cable. I got talking with them about a Quantar power supply that had failed (I had a spare). They had a bunch of retired Quantars and offered me one of the power supplies to keep as a spare. Next thing I knew I was walking out with not only the power supply, but a complete 800MHz Quantar.
I got the radio back online and operational yesterday morning and it has been working great ever since. I think that one of the wireline connections and/or the Zetron HEAR Decoder settings we lost/reset during the PM that was performed. That caused this cascade of events that got worse and worse.
If the tech was young, it may be that he/she had little experience with this setup. I've run across that before, they send the 'new guy' out that has a lot of recent experience on new hardware, but get totally stumped by the old stuff. Sometimes they are reluctant to ask for help.
Now we are looking at purchasing an external power supply. I was informed by the Hospital that they have a hospital wide continuous uninterrupted power supply. We are going to double check that the circuit the radios are powered off of is on that system. That seems like it may alleviate our need to purchase an external power supply with a built in battery backup.
That should be good, but get some info first. We have a whole building (almost) UPS at our PD/PSAP, as well as a large backup generator.
A few years ago the generator controller failed when the power failed. Generator wouldn't start. UPS only had one hour worth of battery backup. Took 2 hours to get a Caterpillar guy on site with a new controller and another hour to get it swapped and running again. Had about 2 hours of hard downtime. Was able to roll 911 over to an adjacent center, and got the radios back up on a little Honda generator we borrowed.
If the hospital has a good maintenance staff with spare parts, if they have more than one backup generator, if they have shore power connection, and their UPS battery system is large enough, that's probably a good solution.
But if lives depend on the radio working, and there's any weaknesses in the maintenance or capabilities, having a battery backup may make a big difference.
Or at least have access to a portable generator and a long extension cord.
I've found, though, that every time you solve one challenge, another one will show up. But that's job security.
Congratulation on the fix. Always rewarding to be able to pull off a fix like that. It's the part of the job I love.