Motorola MTR2000 with Zetron HEAR Decoder Failure

[mmckenna]

That sounds like a good option. I’m not sure I will be able to find that locally today. I am hoping that I can test out the radio today using a couple batteries. I am not sure I could even find a 28V power supply anywhere locally today.

I should be able to use a couple smaller SLA Batteries in series to at least see if the unit will power on. I would not leave them in place to make the radio operational.

Yeah, 28vdc stuff is unlikely to be available anywhere short of an old cell site, or a radio shop. And a radio shop will charge you a ton for one on short notice.

But Tessco and the like stocks them and you could get one shipped out quickly.

A pair of alarm or even car batteries should get it to power up.


For what it's worth, I did just have a Quantar power supply fail on me. It's been running for 10 years, and just gave up. Easy enough to pop in the spare and was back on the air. Haven't had a chance to figure out what failed on it, yet. Sort of not sure I want to put the time into it if they last 10 years. Likely the Quantar will get replaced before the next power supply is needed. Or not….

 

[BlueDevil]

Here is the latest in this debacle.
Both radios showed back up today at the hospital. The tech basically dropped them off and left. When he took the radios with him back to the shop last Friday, he apparently took the power cord with him. Since the MTR2000 has that 3 prong plug with the notch in it. So I have been unable to confirm that the power supply is good or bad. I did see some loose connections coming out of the power supply that could have been the cause of the issue.
I did confirm that the radio will power up with 28VDC. I powered the radio and made some adjustments to the settings on the Zetron HEAR Decoder and the system seems to be working as it should. We are trying to get our power cord back which will not happen right away. We tried modifying a standard heavy duty 3 prong cable without success. I’m assuming that the polarity on those cables is the same as the proprietary Motorola cable, if polarity matters. The power supplies in both radios failed to respond.

 

[BlueDevil]

Here is the power supply the radio company recommended to the hospital.

Motorola CLN1224A MTR2000 FRU VHF 100W PA 132-154 (MTR): CLN1224A

Motorola CLN1224A MTR2000 FRU FIELD REPLACEMENT UNIT VHF 100W RF POWER AMPLIFIER 132-154 MHz for MTR CLN1224A MTR2000 FRU VHF 100W PA 132-154 MTR Usually ships in 7-10 business daysFits Radio Base Station Repeater MTR 2000

www.batterydistributors.com

Seems like a lot of money. Would an external setup be any better?

 

[mmckenna]

I wouldn't spend that much on a single power supply.

The external supply will work just fine, and it looks like you have room for it. For the price of that Motorola supply, you could buy a couple of the Newmar units.

 

[BlueDevil]

It would be nice to find an external power supply that would could run either 24-28VDC or 12-14VDC. I could see the hospital upgrading their system in the future. They could continue to use this power supply with a new base station radio. An external power supply capable of this would offer some more versatility.

 

[mmckenna]

It would be nice to find an external power supply that would could run either 24-28VDC or 12-14VDC. I could see the hospital upgrading their system in the future. They could continue to use this power supply with a new base station radio. An external power supply capable of this would offer some more versatility.

They do make 24v to 12v converters, but it's not what you want to do.

I've never seen a 12v & 24v setup. I've seen plenty of 48v + 24v systems, most cell sites have them (or did), but they are way bigger than what you need.

Do they actually need a 100 watt base station? Would 50 watts get the coverage they need? If so, life gets a lot easier. Replace the MTR2000 with a 50 watt repeater that runs off 12 volts or has it's own 12 volt supply with battery backup and be done with this.

Or, if there are a few repeaters/radios up there, consider adding one large 12 volt system with hot swappable power supplies and a common battery bank.

 

[ramal121]

That's not a power supply, it's the transmit PA. I imagine though a power supply FRU may be in the same range.

If you do have a DC capable power supply, batteries or an external supply would be more cost effective (that is if the the original ones are toast but still accept DC input) You need to match the expected input whether it's 12 or 24 volt. A 100 watt station requires 24 volt. In fact, being the MTR2000/3000 are getting a little long in the tooth and the fact that you may be slightly kludging this to get them on the air again, the suggestion of replacing the base for something a little more modern may be in order.

MTR's use the 20 amp style of power cord, hence the groove. I have modified the 15 amp style with a dremel tool and made it work. The pins are the same in both.

I have no experience with the Zetron HEAR unit but from looking at the manual this is what I gather. One, it connects to the 96 pin system (MRTI) connector for receive audio and if needed transmit audio plus PTT. It also bridges the 2W wireline. When the correct DTMF string is decoded then the unit sends an EIA control tone to the wireline. The MTR would have to be programmed to respond to this tone as a wildcard to open receive audio to the wireline. I haven't looked at the MTR cps to see exactly how this happens. Not sure how it goes back into silent mode, maybe a timer that send a different tone to the wireline?

Regardless, proceed at your discretion. Information is given with the idea you will use this when you beat up on the tech and sound like you know what you're talking about!

 

[BlueDevil]

Knowing that the 24-28VDC power input on the rear of the radio seems to work I think that might be our best options. Now we are trying to find the quickest, most cost effective option to get the radio back online until a more permanent solution can be agreed upon. Whether that’s purchasing a replacement internal power supply, external power supply or just buying a completely new radio. The new radio solution might be the best but would definitely require much more time and money than any of the other solutions.

For its routine use, I think the hospital could get away with 50 watt transmitter. However this radio is intended to operate as a primary means of communication among other hospitals in this region of the state in the event of a disaster or something similar. In this situation, the hospital would want every watt of power they can get.

 

[a417]

MTR's use the 20 amp style of power cord, hence the groove. I have modified the 15 amp style with a dremel tool and made it work. The pins are the same in both.

I have done the same for 'in a pinch' repair. You don't even need a dremel, you can do it with a boxcutter.

 

[BlueDevil]

I reached out to some of my radio tech friends that live in the area to see if they happened to have any external 28VDC power supplies. One of them does have a spare power supply from the old GE Mastr III base station/repeater radios. He is going to let me borrow it to get this radio back online and operational until. This will give the hospital some time to figure out what their long term solution is going to be.

Because it will be more cost effective and require less work, I think I am going to suggest to the hospital that they purchase an external power supply. This will allow them to continue to run the system they already have in place. This radio gets used dozens of times a day but each time the radio transmits, it’s only for a few seconds at a time.

I was initially thinking of trying to find a 12vdc and 28VDC combo power supply with the idea that this next power supply might outlive the current MTR2000 and be useful for powering the next new base station radio. It doesn’t sound like many of these exist.

What is everyone’s recommendation for a 22-31vdc power supply? I have been looking at the NewMar link provided by @mmckenna. I don’t think we need anything real fancy or expensive.

 

[mmckenna]

If you just want a basic 24v power supply to get the thing back on the air, then:

https://www.tessco.com/product/rack-supply-20a-24-29v-482922

I've had a good experience with the Duracomm stuff I've used. Price isn't bad, especially if this may be a short term solution.

For what you are describing, I think I'd install something that can support a battery to keep the thing on the air while the generator spins up to speed. If it's that critical to hospital operations, it's something that they should consider. But make sure the tone remote is powered also...

 

[12dbsinad]

Here is the latest in this debacle.
Both radios showed back up today at the hospital. The tech basically dropped them off and left. When he took the radios with him back to the shop last Friday, he apparently took the power cord with him. Since the MTR2000 has that 3 prong plug with the notch in it. So I have been unable to confirm that the power supply is good or bad. I did see some loose connections coming out of the power supply that could have been the cause of the issue.
I did confirm that the radio will power up with 28VDC. I powered the radio and made some adjustments to the settings on the Zetron HEAR Decoder and the system seems to be working as it should. We are trying to get our power cord back which will not happen right away. We tried modifying a standard heavy duty 3 prong cable without success. I’m assuming that the polarity on those cables is the same as the proprietary Motorola cable, if polarity matters. The power supplies in both radios failed to respond.

Just take any IEEE power cord (computers, power supply's, etc all use them) take a Dremel tool and grind a notch into the plastic and plug er in. Keep in mind the Motorola IEEE cord is larger gauge than most others, but if you're not transmitting it'll be fine. Most IEEE power cords are 18 or 16AWG.

PS: I hope your hospital finds another competent radio vendor.

 

[BlueDevil]

I was able to borrow a power supply for a M/A-COM MASTR III radio from a neighboring City’s radio shop. We made the power cable from spare cables and were able to use the stock DC connectors on both sides. I am very thankful to have many contacts and resources.

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.

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.

I am also having discussions with the Admin about the performance of the radio tech and the radio company. So far the Admin is really receptive of my input.

 

[mmckenna]

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.

 

[BlueDevil]

The radio tech did appear to be younger but not necessarily new. He admittedly didn’t know much about this radio system in particular. Although it is really a pretty basic system. A base station radio with a 2-wire tone remote. I agree with cutting some slack in similar situations. However there were several things that occurred that didn’t require advanced skill, knowledge, or experience. To name a few; He destroyed the wireline connection on the back of one of the radios. He claims to have confirmed the radio was working normally after completing his PM but the next days requests the FD bring some portable radios over for him to use to troubleshoot the radio. My sympathy vanished as these things and other things continued to happen. I have been the new guy many times and understand the benefit of patience and understanding, when appropriate.

 

[mmckenna]

Got it. That's too bad he didn't ask for help. I agree with finding a new shop.

Having a tech that will ask for help when needed is a good sign. One that doesn't raises a red flag.