R1225 intermittant

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arlojanis
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Joined: Mon Jan 28, 2002 4:00 pm

R1225 intermittant

Post by arlojanis »

Is there a common problem that would cause a R1225 repeater to work some days and not other days? I have not been at tower when repeater was not working. I have re-soldered capacitors in power amp and did not help.
"The world runs on radio."
Jim202
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Re: R1225 intermittant

Post by Jim202 »

arlojanis wrote:Is there a common problem that would cause a R1225 repeater to work some days and not other days? I have not been at tower when repeater was not working. I have re-soldered capacitors in power amp and did not help.


Are you trying different radios to key the repeater or just your radio?

Give us something to work with here as to how you are coming to the conclusion that the repeater isn't working.
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arlojanis
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Re: R1225 intermittant

Post by arlojanis »

Nobody can talk on channel 4. It is like the repeater is dead. Later it is OK.
"The world runs on radio."
Jim202
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Re: R1225 intermittant

Post by Jim202 »

arlojanis wrote:Nobody can talk on channel 4. It is like the repeater is dead. Later it is OK.


Without being there, I would put my money on one of three causes.

1. Radio is loosing power that it runs on.

2. Radio has a receiver problem either swamping the input with a signal from maybe an intermod or the receiver is rolling over.

3. Receiver tone squelch is not working all the time to decode the correct CTCSS tone.

Without being at the tower when the problem takes place, everything is pure speculation. Is there any battery backup on the repeater to carry it through any power failures? If not, I would suggest trying to add a battery and see if the problem goes away.

The rest of the trouble shooting will require test equipment and a fast trip to the tower to try and catch the problem while it is occurring.

I will give you an example of a problem I had with a GE Mastr II base station a number of years ago. It would stop transmitting when it got cold. The first time I went to the tower, I got the door of the radio cabinet open and the problem went away. The next day it did it again. So I left the door off the cabinet. The next day it did it again. This time I was ever so careful in trying to tilt down the radio to get access to the radio itself. It seems that any vibration to the radio chassis would cause the radio to start working. So this time I left the drawer in the down position and removed the top cover so I could be able to get at the different components. Back the next day after it failed. Managed to be careful and found that if I moved one of the TX multiplier coils, I could control the failure.

Pulled the can off the coil and found a cold solder joint on one of the coil connections. Soldered the coil wire connection and the problem never came back.

So you could be in for a number of trips to the tower to even narrow down the problem area. Good luck in locating the problem.

Jim
Wiregeek
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Re: R1225 intermittant

Post by Wiregeek »

Don't forget that you're also dealing with that most corrosive and untrustworthy of substances, Other People. I recently had a job to fix a Quantar that had gone just about completely deaf - if you were within ~1 mile of the repeater, and mostly deaf outside that range. Went through and swept and wiggled and checked from antenna to the RSS port and found nothing out of the ordinary, then on my way out the shack for a smoke noticed a light on a GE Mastr III sitting next to the Quantar rack.

The Mastr III was the repeater the Quantar had replaced. Some brilliant person had come up after a recent earthquake and plugged the old thing in and turned it on... No antennas on TX or RX, but the cursed thing would occasionally key up, since it had the same frequencies as the Quantar, and just puke RF everywhere...

I zip tied the power cord into a 2" bundle zip tied to the internal structure of the Mastr III and wrote bad words on it.
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fogster
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What radios do you own?: XTS2500/5000, XPR7550/5550

Re: R1225 intermittant

Post by fogster »

I've actually just bought a used R1225; hasn't even arrived yet, but I was reading documentation online. One thing I didn't realize is that it's not rated for 100% duty cycle at full power. The high-power model will only do 100% at 25W. No idea what your usage is like, but is it possible you're just driving the thing into overheating?
arlojanis wrote:Nobody can talk on channel 4. It is like the repeater is dead. Later it is OK.
Is "channel 4" the repeater's channel, or are you switching channels on it? How long is it offline for? Is it actually days at a time? The first thing that came to mind is that maybe it's tripping a time-out timer, but that wouldn't make sense if you were looking at it for days.

As others have hinted at, it could be almost anything, and it'd be hard to know without driving out there when it's offline and figuring out what's up. It could also be any number of RF or power things, but I thought I'd toss a few ones out just in case.
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arlojanis
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Re: R1225 intermittant

Post by arlojanis »

Channel 4 is the channel on the portables. Repeater was dead for several hours. My first idea was bad solder connections in power amp. I am wondering if there are other things that happen often with this model. Repeater has not gone off in several weeks now.
"The world runs on radio."
Jim202
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Re: R1225 intermittant

Post by Jim202 »

arlojanis wrote:Channel 4 is the channel on the portables. Repeater was dead for several hours. My first idea was bad solder connections in power amp. I am wondering if there are other things that happen often with this model. Repeater has not gone off in several weeks now.



The best thing to do at this point is to pull it out, put it on the bench with a service monitor and see just what it is doing.

No test equipment, no fixing it. Simple facts of life. You could have so many sources of a problem, trying to figure it out from the couch is like trying to empty a swimming pool with an eye dropper. Your just in a loosing battle here.

Let the group know what you find. Also while it's on the bench, take a look at the purity of the transmit signal to see how clean it is.
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