Midland MXT400 will not transmit shows PUC100 on screen

[traderman]

Midland Micro Mobile GMRS MXT400 ....  When I press the PTT on the microphone the unit beeps, shuts off and turns on again and shows PUC100 on the screen. Also when I turn on the unit it also shows PUC100 for a second.  I've factory reset twice and tried 2 different antennas and sent question to Midland support but have not received a reply yet .... Any help would be appreciated !  Thank You 

[OffRoaderX]

26 minutes ago, BoxCar said:

If the radio has been sitting unused for several years, it may be some of the wet (electrolytic) capacitors have dried out. 

I'm curious - would this happen only if its setting unused, or can this still happen when a device is still used but just as old?  ie; does using a device make it last longer than when its just sitting in the closet ?

 

[Screech]

Has the radio worked in the past or is this issue on first setup? What brand/model antennas have you tried? Were the antennas using the same antenna mount? How are you powering it?

[SteveShannon]

It would be nice to have a listing of error codes, wouldn’t it?  It appears to show PUC100 whenever it’s first powered up. Might simply mean that it’s passed its power on self test, or maybe it means something else entirely.

I think Screech probably hit on it.  Put a voltmeter on the power line input to see what’s happening when you transmit. See if it’s dipping low.

Then try adjusting the transmit output power to its lowest setting.  Does it still reset when you PTT?

[traderman]

Upon further trying to transmit the error shows PUC 1.00 not PUC 100 as I previously wrote... oh well these tired old eyes! I've powered it up on my Bentley 12volt regulated power supply and powered up in both vehicles. Still get the same error.  As I remember it worked fine a number of years ago just been sitting in my closet in the house .   Thanks for the replies and still trying to figure this one out !  73's  

[SteveShannon]

Most mobile radios like to see 13.8 volts. Transmitting requires more current, sometimes a lot more. If your power supply cannot provide that much current the voltage will drop to the point where the radio will reset. I suspect that’s what’s happening. Watching the input voltage like I suggested above would tell you if that’s happening. 

PUC 1.00 sounds like it could be a firmware revision, which would seem reasonable to display on startup. 

Edited May 27, 2022 by Sshannon
Another idea

[BoxCar]

If the radio has been sitting unused for several years, it may be some of the wet (electrolytic) capacitors have dried out. It may be cheaper to buy a new radio than to send that one in for checkout and repair if needed.

[MichaelLAX]

27 minutes ago, OffRoaderX said:

I'm curious - would this happen only if its setting unused, or can this still happen when a device is still used but just as old?  ie; does using a device make it last longer than when its just sitting in the closet ?

 

That's the same question I had for my Urologist!?! 

He said: "Use it or lose it!" 

Wikipedia's take on the issue

[traderman]

Hello   OK problem solved and should have thought of this after years of " playing with radios" but as we get older sometimes the obvious doesn't hit us in the face !!!  Changed the cigarette lighter plug to a more heavy duty type and transmits like a charm ! Thank you to Sshannon for the posting about power requirements which lead me on the right track   73's to all and thank you !   

[Screech]

You're welcome.

[SteveShannon]

2 hours ago, OffRoaderX said:

I'm curious - would this happen only if its setting unused, or can this still happen when a device is still used but just as old?  ie; does using a device make it last longer than when its just sitting in the closet ?

 

I don’t know why, but I’ve seen it most often with old stored equipment, including old new stock UPSes. That may be because it’s very recognizable when you plug in a piece of equipment and a cap fails, whereas when they’re being used it looks like it just wore out. 

[scorpion1200]

On 5/27/2022 at 4:06 AM, traderman said:

Midland Micro Mobile GMRS MXT400 ....  When I press the PTT on the microphone the unit beeps, shuts off and turns on again and shows PUC100 on the screen. Also when I turn on the unit it also shows PUC100 for a second.  I've factory reset twice and tried 2 different antennas and sent question to Midland support but have not received a reply yet .... Any help would be appreciated !  Thank You 

Reach out to Roger French he is the go to person for midland.

Roger French <rfrench@midlandradio.com>

 

[SteveShannon]

10 hours ago, scorpion1200 said:

Reach out to Roger French he is the go to person for midland.

Roger French <rfrench@midlandradio.com>

 

He already solved the problem by switching to better power connections.