MTR2000 very warm; cooling fans? when do they activate???

[chipjumper]

Have a MTR2000 VHF and if viewing from the back of the unit, the right heat sink marked "RX" is very warm. The cooling fan is not running. I have heard it turn on for literally just a second (just now actually! there is heavy radio traffic). I checked it 20 minutes ago when there was no radio traffic and it was still hot to the touch and the fan was not on. Other side is very cool.

I power cycled the machine and the fan has been running constantly for the last 15 minutes. Is this a bad sign? Why wasn't it running before???

[thebigphish]

if you powercycled the machine and the fan came back to life and ran after for 15 minutes, i'd betchya good money that the fan has a bearing in it that's about to $hit the bed. My guess is it would have started before you powercycled it if you had tapped the blade with a ballpoint pen or soemthing...OR, you have something that is stuck (fuzz, dirt, FOB) inside the fan radius that is blocking it, and the voltage drop of the cycle dropped the strain on it and it fell free...clean it out, check the path, replace the fan if it's suspect...better than replacing that PA when you cook the deck when that sucker overheats...cool running stuff tends to last longer.

[chipjumper]

I guess I'll keep monitoring it over some time

[KG6EAQ]

I guess I'll keep monitoring it over some time

Or just replace it now and not worry everyday of your PA releasing the magic smoke. That smoke is much more expensive in the MTR than in a Maxtrac

[thebigphish]

I guess I'll keep monitoring it over some time

Or just replace it now and not worry everyday of your PA releasing the magic smoke. That smoke is much more expensive in the MTR than in a Maxtrac

yeah chip, i'd def. just replace it with some hi flo fans and def. sleep a little sounder knowing there are GOOD fans in there now...cost you, what...20 bucks to do them ALL at once?

just don't let the smoke out.

[Adamwest]

Hi

I would not run the unit until I replaced the fan. The normal cycle time for these fans is around 5 to 7 minutes. You are talking about a $4500 plus radio replace the fan.

good luck

adam

[chipjumper]

Its definately not a bad fan; can't be!

I power cycled it today and of course the fan turns on for about fifteen minutes and shuts off. When it shuts off the power supply is only lukewarm. I waited about two minutes and power cycled it again (I could tell the supply was getting a little warmer). The fan came on again but this time for only a couple minutes --- until the supply was lukewarm again then it shut off.

Now, I let the MTR2000 sit until the power supply got back up to its "normal" temperature of superhot (cannot keep palm on it, very hot) and cycled the power. The fan comes on and shuts off when the supply cools down.

Now - what is the problem here? Why does the fan only turn on when the power is cycled? It is a fact that there is not a timer that shuts the fan off after a power cycle - remember it was only on for a few minutes when the supply was just barely heating up.

A technician was called recently and found no problems. I am assuming he didn't know what he was looking for. Is there a temperature sensing module?

[wavetar]

There is definitely temperature sensing to activate the fan. Normally upon power-up the fans only run for a few seconds as a check, nothing more. The fact you have them running for varying lengths of time indicates a problem to me. Have you or the technician gone into the diagnostic metering screen to see if the temperature is being sensed?

Todd

[chipjumper]

wavetar - i sure haven't gone to the temp diag screen. Can I access this via RSS?

I'm assuming the tech just pulled the front cover off and looked at it...

Anyone know or can tell me some pinouts of the MTR2000 for the following:

-Speaker RJ11 connector up front
-Rear remote interface (for remote handset/tone remote)

[HumHead]

The pin outs for most of the MTR2000's connectors (and programming cable) are included in the RSS help file.

I don't recall the speaker pin out off of the top of my head, but I do recall that it is not really a speaker output. It is line level out, and you will need an amplified speaker to make use of it.

[Dan562]

Hello ChipJumper,

You haven't stated whether this [/i]MTR2000 is Relay Rack mounted or in a cabinet? In the Instruction Manual # 68-81096E30 under the Installation section Page # 2 & 3, it states the station is capable of operating at temperatures between -30C (-22F) and +60C (+140F). The manual also states that the end user must provide a well ventilated area around the station, i.e. by not stacking a bunch of boxes on or around the unit and mounted in a WELL ventilated cabinet. There's also a section that indicates how many racking units 3 RU are required (left open) between stations or second receivers and/or other pieces of equipment for ventilation purposes.

As your observation about the station, all connectors are located on the front of the Station Control Module for programming and other function. The connector are from left to right BNC 5/10 MHz External Ref signal, RJ45 (Amplified) Service Speaker, RJ45 RSS I/O Port and RJ45 Microphone Jack. There's nothing on the station's rear other than the I/O Telco Wire Lines for TRC Remote connections. Without the Standard RSS and a laptop computer ... you're basically hung trying to evaluate the station.

The Thermistor that controls the Fan is mounted internal in the RF Power Amplifier, it's 100 K + 10% 240mW. It drive 2 separate IC Gates U4505 and U4508 controlling the Temperature Sensing and Fan Enable circuitry within RF Power Amplifier assembly. I'll make the following statement, the temperature range is in the machine language code for turning on and off the external Fans and all the RSS can do is "monitor" if it is acceptable or not. I would almost say the Fans are working correctly per the information given.

Dan

[chipjumper]

it is rackmounted inside of a short motorola cabinet; about 3.5ft tall.

In regards to the supply cooling fan; how do you explain the fan only staying on and cooling the supply when the power is cycled? It will NEVER turn on again until the power is cycled.

Again, a test I did was cycle the power...wait till the fan shuts off (and the supply is barely warm). Wait a few minutes until the supply starts to heat up. Cycle the power and the fan stays on only for a couple minutes---when the supply is cool again. From that info we can see that the fan sensor knows that the supply is too hot and it needs to turn the fan on. Also, the sensor knows that the supply is cool and needs to shut off.

Back to the main question: why does the sensor only sense after the power is cycled?

[Dan562]

Hello ChipJumper,

First, from what you have provide about the size, this station you have is mounted in a X52 Option Cabinet 30" High.

Regarding why the internal muffin Fans only turn on for a short period of time .... maybe 15 seconds after the Primary Power is recycled is very simple. The MTR2000 Series Base / Repeater Stations provide a Self Test feature that's automatically programmed in to the machine language software code. If you have ever removed the plastic front cover from the station, watch the sequence of LEDs on the Station Control Module while it's going through boot up process. If there would be something wrong, you would know immediately with Flashing LEDs .... indicating some form of a failure.

By the sequence of correspondence, it appears that you don't have the authorization for access to the equipment's RSS. You've had a Field Service Technician out at your location to troubleshoot your complaint. I would say, don't assume the Field Technician doesn't understand the equipment or the complaint as he was authorized to perform the service.

Possibly you don't understand this /\/\ product and how it normally operates. I provided you the Instruction Manual number in my previous comments. If you take the time to find your copy or order that manual, please read it from the front cover to the rear cover and you may have a better understanding of the equipment.

Dan

[chipjumper]

I can see what you mean by why the fan activates for only a short period of time. Then why when the pwr is cycled it only stays on for a short period of time when the pwr supply is cool and not for a long time when the pwr is cycled when the supply is very hot?

My point here is that somewhere inside it knows that it is too warm therefore keeping the fan on for an extended period of time --- like 15 minutes compared to 15 seconds. If it knows that it needs to keep the fan on until it cools the pwr supply down, why does it only "do its job" when the power is cycled?

When I get a chance I will interface into the radio with RSS and I will try to aquire a copy of the manual.

[wavetar]

It would seem to me the station may be sensing the temperature correctly, but whatever path it takes at that point to enable the fans is not working. Upon power-up, the enable path might be different, thus allowing the fans to run until the temperature is proper. 'Bout all I can figure without seeing it.

Todd

[Dan562]

Hello ChipJumper,

It seems I'm having a difficult time trying to relate equipment design parameters to you. It appears you like to experiment with electronic equipment in this case the T5544 MTR2000. You want to understand why and how everything works together down to the smallest detail.

Typically this piece of equipment operates at a very warm if not considered hot metal case temperature. Depending on which way you are facing the Base Station, from the front the Transmitter/Power Supply/Fan is located on the right hand side and if you're facing the station from the rear the Transmitter/Power Supply/Fan is on the left hand side. Now that I've established this fact, there should be no confusion which module assembly we are communicating about.

If perhaps you've noticed I mentioned that this includes the Transmitter / Power Supply / Fan as all in one metal module assembly. I will not assume you completely understand electronic theory but can believe there will be heat related disappation from Power Supplies under a normal operating mode. Now think about this, the Power Supply is producing all of the necessary Voltages and maintaining the Current levels for every module in the station .... Wouldn't you believe this could produce "X" amount of heat? You also have the RF Exciter and Power Amplifier being cycled on and off at intermittent rate adding to the heat disappation. Incidently your have a 500 Watt Power Supply in that station. Watts equal heat disappation ... you can do the formulas.

Since you haven't acquired the /\/\ Instruction Manual as of today, I researched the CLN1220 500 Watt Power Supply Module in this manual under the Power Supplies (White Tab Section) on Page # 8 and in particular, the Fan Control Line. Here's what it states:

The supply incorporates temperature sense/Fan enable circuitry for controlling a 12 VDC fan mounted on the surface of the heat sink assembly. The power supply circuitry senses the internal temperature of the power supply. When the internal temperature exceeds +60C (+5C), +12 VDC is enabled at J1-1 to turn on the fan. The +12 VDC fan supply is derived from the +14.2 V output. Power to the fan is off when the temperature is below the set limit. The fan turns on for approximately 10 seconds when power is first applied as a diagnostic indicator that the fan is functional.

The sensing components send digital signaling between the Transmitter / Power Supply / Fan assembly and the Station Control Module on the Serial Peripheral Interface (Logic) Bus and this is determined in the machine language software written code.

If you haven't had any station failures so far, Why are you worried? You haven't stated how the station is being used, Simplex Base, RA/RT Link Base or Base Repeater configuration?

I would say if this is not good enough for you, I would suggest contacting MOTOROLA System Support Center directly in Schaumburg, IL and have your Credit Card available for Consulting time involved ... I think there's a four hour minimum at $150.00 per hour but they could have raised that cost upward. If you should step up to the challenge, I would also suggest to have a calibrated temperature probe and recording equipment so the MTR Product Group can evaluate your engineering complaint properly. They don't use "Hand Touch" for measuring the metal equipment case temperatures.

Dan

[wavetar]

The fan turns on for approximately 10 seconds when power is first applied as a diagnostic indicator that the fan is functional.
Dan

Dan, I can tell you have a lot of experience dealing with many things Motorola, and I respect you for that. But, it appears that you've missed the point of chipjumper's findings. Look at your quote above...10 seconds is not 15 minutes...I am aware the fans turn on for several seconds upon a cold restart... and his station responds accordingly if restarted when 'cold'. If restarted when 'hot', the fans will stay on for as long as it takes to be brought down to the desired temperature. This is also normal, if you've ever restarted an MTS2000 when 'hot'. The problem as it appears is that the station will not activate the fans at any other time...the PA or PS can get as hot as it wishes...the fans will NOT kick in to cool them off...at least, this is how I'm reading it. I'm sure chipjumper will chime in if I'm wrong. 60 degrees C will not burn your hands...his MTR is getting hot enough to do exactly that.

If you haven't had any station failures so far, Why are you worried?

Dan

It's called 'preventative maintenance', or perhaps 'pre-emptive checks', but it's a legitimate problem that he seems to be having. We run a lot of MTR2000 repeaters, none get 'hot' to the touch...my experience shows the fans kick in when the PA/PS is 'warm' to the touch. The MTR is a 'continuous duty' unit, and is thus very robust & difficult to get to fail...but overheating WILL cause it to do so sooner than later. He has a legitimate concern.

I would say if this is not good enough for you, I would suggest contacting MOTOROLA System Support Center directly in Schaumburg, IL and have your Credit Card available for Consulting time involved ... I think there's a four hour minimum at $150.00 per hour but they could have raised that cost upward. If you should step up to the challenge, I would also suggest to have a calibrated temperature probe and recording equipment so the MTR Product Group can evaluate your engineering complaint properly. They don't use "Hand Touch" for measuring the metal equipment case temperatures.

Dan

This is the exact reason why people come here in the first place...free helpful advice which can sometimes help to avoid charges such as these. We don't always have the answer, and in those cases, the real hardcore engineers in Schaumburg are well worth the money. I advised above to use the diagnostic screens in the RSS to try & determine exact temerature of the station when considered 'hot'...then there's no doubt about the subjective nature of 'feeling'. The fans should kick in at 60 C...if they measure 85 C with no fan action, then we know there's a problem. Let's wait & see what chipjumper finds next, before becoming impatient, ok?

Todd

[chartofmaryland]

yeah

[chartofmaryland]

Sounds like chip needs to get another power supply and some new fans, hook them up and turn them on. Fans running all the time will not be as much of a worry as ones that run when they want to. Get more than two if possible, when one fails the others will keep gettin it.

And be DONE with it. I mean, we're talkin about FANS, FANS, just stupid FANS, hehe, and they are protecting a 2700.00 + dollar repeater? I'd go to Wally World and buy a freakin AIR CONDITIONER and set it up at the back of the cabinet. Simple, its alot of dough for when something apparently this complex goes bad, get right back to basics when something of this caliber goes iffy.


This tech advise will cost you a whole $0.00 CREDIT CARDS ONLY

Your welcome


CHART

[Dan562]

Hello Todd and ChipJumper,

Todd, you state that you've got quite a few MTR2000 stations out in the field in repeater applications. Are those MTR2000 stations being used in Conventional or Trunked systems? What percent are used in each application? How hot would you estimate any of those metal case heat sinks are in normal operation? And here’s an interesting thought, if you can lay your hand on the any of the heat sinks, would anyone else concur with your temperature findings?

Most people I know differ from night to day on their touch sense when near something cold, warm or hot. What is hot to one person may be warm to the next and vice versus. How often do the fans turn on while you’re out at your sites? During normal preventative maintenance scheduled work, how often have you just swapped out the fans? Once every 3 months? Once every 6 months? Or once a year? Are your sites temperature controlled or not?

Since I do not know "ChipJumper's" technical knowledge in basic electronics, I hesitate to have him start troubleshooting the MTR2000 station and randomly replacing suspected components. Most of the replaceable components are Field Replacement Units (FRU). I have yet to be acknowledged that he's got an Instruction Manual yet, Laptop Computer with the most current RSS, hand tools and most of all "the authorization from his management" to perform any work on the station.

Most on this troubleshooting can take the station down, “Off the air” for several hours to properly evaluate the wiring harnesses and plug connectors, assembly interconnections, XMTR and P. S. assemblies & connections, the Backplane PCB and the station control module. As good as the MTR2000 stations are, there’s no quick fix or repair when something appears to be working incorrect or intermittent. Of course that statement holds true for troubleshooting most products.

I need to address this question to “ChipJumper”, everytime you remove the primary power 121 VAC from the rear of the station does the Fan turn back on for only 10 seconds or 15 minutes continuously, when you perform this function?

While you’ve been watching the erratic fan operation, have you ever reached inside the cabinet and genteelly wiggled the fan wiring harness to see what might happen?

If you have had the front and rear doors of the station, the black plastic front faceplate removed, have you just push the edge of the Station Control Module and tapped on it with a plastic screwdriver handle and does the fan activate? Tap around (not hit) on the Power Supply and the XMTR assemblies and notice if the fan activate.

Have you taken a Digital Voltage Meter, measured the DC voltages on station’s Backplane and recorded the information in a journal for future reference material? Do these very carefully because it’s so easy to slip the DC test probe across PC traces and damage them or blow the fuse.

Genteelly push on the Backplane while the stations hot to your touch and take notice if the fan activates.

If you haven’t noticed, I’ve be asking you to perform very simple troubleshooting techniques which I need concise answers as you do them. Record anything that appears unusual or erratic while you’re doing each task.

On the MTR series station the RF Power Amplifier and Power Supply are attached to each other, they interface to the Backplane and the Station Control Module is where the Host Microprocessor is located (the brains of the entire station). The internal communications are transferred on the Serial Peripheral Interface Bus between the SCM and the Receiver, Exciter, PA, etc.

The Power Supply is a Black Box (built by an OEM, no other information is supplied) interfaced to the PA and the Backplace. When troubleshooting the Power Supply, it’s either Good or Bad … no in between not even for
/\/\ Infrastructures Depot Operations (the factory’s authorized repair center). Internally in this Black Box Power Supply there’s the Temperature Sensing circuitry and the Fan Switch Enable that feeds the 12 VDC to the Fan. There’s no block diagram lines indicating how this is fed from the RF PA, probably osmosis (magically).

Basically the fan should activate between 55C (130F) Low, 60C (140F) Medium and 65C (149F) High according the /\/\ manual. I referenced the temperature conversion information from: Reference Data Radio Handbook, ITT Published in 1979.

Now I suppose you could take Chart's advice and connect a pair of muffin fans to the station ... they need not be 12 VDC, you could use regular 121 VAC muffin fans but does that reallt address you question or mask the problem. It's your choice.

Dan

[chipjumper]

Wow, I never got notification of you reply Dan. Whenever this MTR2000 is power cycled, the fan will run for a long time if the base is warm. Maybe there is a different minimum temperature to activate the fan when the unit powers up?
Does this run something like a Power On Self Test when it is power cycled like a PC?

I have been sitting next to it for the last hour (since our county's radio system has been down) and I just noticed that the fan has been running for over the last hour. Very interesting since this is the longest I have ever heard it run.

[Dan562]

My. my. you've just discovered the MTR2000 station's muffin fan and temperature sensors are performming correctly. And there are different temperature levels that the internal heat sensors activate on.

In the written machine language code (software) within the RSS, when the station's unplugged from primary power 121 V AC source and then the plug is re-inserted into either the rear of the station or 121 V AC wall outlet socket, the station's software performs a SELF TEST sequence described in my Post: Thu Nov 18, 2004 8:22 pm Post subject: MTR2000 Station Ventilation / Fans or as you have stated in your most recent Post: Fri Aug 12, 2005 6:10 pm, "this runs something like a Power On Self Test when it is power cycled like a PC" ... Exactly.

Dan