Batboard

I have a VHF MTR2000 on a hill nearby, wireline tone control. I was just informed that for about the last 9 months, the base keys up by itself every night at 12:03 am, and will stay keyed for quite some time. They key it from dispatch and it clears. I've looked in the software to see if the automatic station ID, or some kind of alarm is turned on, and everything looks fine.

Any ideas??

Thanks-
Bill
Bellingham, WA

Well thats a new one. Do you have any audio recording equipment on this system and is voting or just the single station? Is there any aound or just dead keyed

It is 4-wire control, and the RX side does go to a voter. The other two stations, also MTR2000's, are also tied to the voter. As far as recording, the three stations are controlled from a Zetron 4000 series console, so the voter outputs and the recorder are tied to that.

The strangest thing is that this has been in place and funtional for a long time, with no changes that I know of. I suppose I could have some sort of hiccup in the Zetron that is keying up the station at the same time every night. Maybe I will try going up there tonight and removing the telco connection to the base and see if it still comes up.

At least it isn't intermittent!

Check for cross talk on your phone lines. The telco might have changed your path and the guard tone might be bleeding through from your voter side. Also check to make sure you have function plus LLGT to key the radio, otherwise it can false.

You may have a Controller problem.




PSB # 910



DATE: November, 1999

EXPIRES: 12/1/2000

SUBJECT: MTR2000 STATIONS CAN INTERMITTENTLY LOCK UP DURING POWER-UP

MODELS AFFECTED: MTR2000 (T5544A, T5731A, T5766A, and T5769A) WITHOUT ARGUS BATTERY BACKUP WITH A SERIAL NUMBER RANGE OF CYA THROUGH CZW

SYSTEMS AFFECTED: CONVENTIONAL AND TRUNKING AC POWERED MTR2000 STATIONS

SYMPTOM: Station is unable to receive or transmit any signal or perform any other station function. All LEDs on the control module are continuously on



DESCRIPTION OF PROBLEM: This error occurs very rarely in some stations only, but a momentary AC power failure usually triggers this problem. When main power to the station is restored, all LEDs on the control module turn ON, but the station does not proceed to reset. Removing power from the station and reapplying power after a brief wait (approximately 30-sec.) restores normal operation.

NOTE: This problem does not occur in DC only stations.

CAUSE: The problem occurs when the microprocessor controlling the station operation does not receive an electrical reset pulse from the supervisory IC on the control module to start the reset sequence after a power interruption.

RESOLUTION: The TCN6273 control board must be replaced.



If you experience this problem, we strongly recommend you obtain a replacement controller board (TCN6273) at no cost, by contacting the System Support Center at 1-800-221-7144 and make reference to this bulletin. This problem can occur on stations which shipped from January 1,1998 through November 15, 1999 with a serial number range of CYA through CZW



I don't know how old your station is but, it states this can be delayed from date of shipment.

If your station is newer, then you should make some time and be there around 12:03, plug in you laptop and watch the station. That may be your only true way, but this fits with power turning off or say the phone company does tone testing around that time and happens to send a set of tones close to your station keying.

Hard to say without guessing after that and I am poor on guessing.

CoM

That PSB deals with a completely unresponsive, ie: "locked up", station after a power glitch, which doesn't seem to be his issue at all.

I suspect the Zetron is doing some sort of self-testing at midnight which results in the station keying. Has the console been upgraded at all, perhaps 9 months ago when the problem apparently started?

I'd be real surprised that the Series 4000 is issuing a Tx Key command on its own, but there is a port on the console backplane and a software package that will let you monitor, and record to file, each an every command processed by the Series 4000. These are time and date stamped, so if you can tie down the moment the problem arises, you could check to see what the conole did at that moment (if anything).

I think it is highly unlikely that it is the MTR2000 itself. I don't think there is a clock in that thing that knows it is midnight to do anything. So my bets are some piece of dispatch or infrastructure. We also know it is not a remote receiver site because the line card in the voter would time out and fail that site. So we know the problem is either the console, the voter itself, or the phone lines connecting all of this together to the station.

If you can get to all the equipment and phone pairs, this should be pretty easy to trace. Put a butset or monitor on the TX pair. I assume you will hear something generate an F1 TX and guard tone or this wouldn't be happening. First things, look and see if something is voted. It probably won't be as I mentioned above. Now start disconnecting stuff starting at the console. If you disconnect the phone line from the Zetron and it stops, there you go. Problem is in the console. If not, work your way up until you find it.

My bet is the console. Its the only thing with a clock.

Yes, the MTR does know what time it is...

I just had one that would not decode PL and stayed in carrier squelch operation.

No wireline assoicated with it.

The fix was to power cycle it.

I would do the same for yours and check your clock and reset the clock to almost midnight when you are on site and see if you can isolate the radio from your infrastructure. Say, set it six hours different and see if the problem time moves.



George

There is a FS bulletin about this on the Motorola website. It is a glitch that is related to keyup/keydown conflict between in-unit repeat and wireline control from a comparator.

FSB-10174

It happened to me also in a voted system with TRC wireline control, one time, never before or since.

There is a firmware update to solve it.

I have not done the firmware update yet, and probably won't unless it becomes chronic.

Greg Carttar

The FSB refers to when a mtr is programmed as a repeater, and gets wireline keying commands too, it keys without pl and stays keyed till a station reset or power cycle. That is what the fsb refers too, not this to my knowledge.

Bill - Did you figure this out yet?


Are all the stations transmitters or do you have receivers only in the mix?
A receiver going down could cause this. Is the console getting an open mike?

Ive got a similar setup utilizing several MTR's, a JPS SNV-12, and Zetron 4000 under my watch across the water from you. If it starts doing this it would nice to know why...

We, too, have a whole bunch of MTR-based voted systems, using Zetron 4048 consoles, and have never made the same observation. This is why I doubt it is something native to either the station or the console, but rather some external stimulus.

For what it may be worth, I did have a report of a similar issue with a CentraCom Gold Elite. After a lot of head scratching, it was determined that the keyup was coincident with the timer card switching, a few minutes after mid-night, and, if my memory is correct, only when the switch went in one direction (i.e., either from A to B or from B to A, but not the reverse). I don't recall what the fix was. I was not directly involved, but heard about it after the fact. Zetron "System Traffic" cards (more or less the counterpart to CC timer cards) do not switch on a regular basis, but only if either a failure is detected on the currently active card or the "takeover" button is manually pressed.

George wrote:I just had one that would not decode PL and stayed in carrier squelch operation.

The fix was to power cycle it.

So did I, i just shipped it out for repair. I have a thread on it here.

Our old payphone used to do a "squeak" @ 12:08 every night, and i've never thought about seeing what was coming over the wireline setup @ that time, but i know the phone would make an audible squeak every night without fail. I'll bet the phone telco is gorking your MTR when that test happens.

Bill,

What are you using for your status tone frequency?

This is from years ago so if you've already heard this please excuse the history.

In the 70's sometimes Motorola used to use 2175 for status tone as well as LLGT. We soon found that in 4 wire systems, with some cross talk, that the status tone bleed over between the two pairs would keep the station keyed until something else, like a PTT from the comm center, interupted it.

The solution was to change status tone to the alternate choice of 1950.

Regards, Bob