Howdy, i am new here to the forum and am working on a project involving a motorola micor compa station repeater. I got this unit for free and is complete with all cards. I used it for like a year and recently encountered a problem. When i got it it read on it 'bad tripler', i happened to have a spare and put it in and whalaa it worked for like a year. 2 weeks ago i keyed it up and for half a second it came up then went down and i coudn't hear it anymore. Went out to the site and it was working just really low output power, get 2 feet away and it was static. Not having another tripler and examination of these triplers i couldnt see nothing wrong so i put the tripler back in hoping it wasn't it. Lastnght i replaced the antenna network hoping it was that,,nope it wasn't. Next i replaced the diamond shaped transistor behind the power control board,,and the power control board. Still the same, so i replaced the power amp (75w) and still nothing. I have no more spare parts and the exciter is working just fine so it has to be the tripler. My question is i got lots of these old motorola maxar80 uhf mobiiles laying around 450-470 mhz so i stripped the pa deck off of one. This pa deck according to the model number is 5-15 watts out. If i can decrease the power out to 2 watts it would make a excellent tripler but i need to know how to wire this up i know its possible. This repeater sounded so good when it worked can anyone tell me which coax coming into this pa deck of the maxar is for transmit? there is also 1 thick white heatshrink material surrounding inside is a tiny red/blk/and yellow wire. I was going to use this pa deck output which would typically be for the antenna as input to the micor pa. Help would be greatly appreciated.
Thanks, Greg
KD0IUH
Micor Problem
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Re: Micor Problem
I think you're confused as to what a tripler is. I'm assuming this is a UHF or 800MHz repeater? It would have to be to have a tripler.
A tripler works with the radio's IF to produce the output frequency. It's essentially VHF in = UHF out. It's not a power amplifier, and should not be replaced with a power amplifier.
Read this:
http://www.repeater-builder.com/micor/m ... ipler.html
The answer is no, it won't work.
The MICOR is a simple enough radio to work on that you should be able to use internet resources and some technical skill to fix what you have. Parts are plentiful enough on eBay that you should be able to find replacements fairly easily. You need to read the manual and do some proper troubleshooting to determine exactly where the problem is, and either replace the failed component, or replace the failed module.
"Shotgunning" things as you've been doing doesn't always work, as you've seen.
My $0.02 is that you spend some time closely poring over the documentation on the MICOR at the repeater builder website. I'll direct link to it so you don't have to trip and stumble over Mike Morris's pointless "humor" trying to find the right section. http://www.repeater-builder.com/micor/#ANY-Station
Hope this helps. Personally, I'd put the thing to pasture and upgrade to a CXB series MSF 5000, but it's your baby.
A tripler works with the radio's IF to produce the output frequency. It's essentially VHF in = UHF out. It's not a power amplifier, and should not be replaced with a power amplifier.
Read this:
http://www.repeater-builder.com/micor/m ... ipler.html
The answer is no, it won't work.
The MICOR is a simple enough radio to work on that you should be able to use internet resources and some technical skill to fix what you have. Parts are plentiful enough on eBay that you should be able to find replacements fairly easily. You need to read the manual and do some proper troubleshooting to determine exactly where the problem is, and either replace the failed component, or replace the failed module.
"Shotgunning" things as you've been doing doesn't always work, as you've seen.
My $0.02 is that you spend some time closely poring over the documentation on the MICOR at the repeater builder website. I'll direct link to it so you don't have to trip and stumble over Mike Morris's pointless "humor" trying to find the right section. http://www.repeater-builder.com/micor/#ANY-Station
Hope this helps. Personally, I'd put the thing to pasture and upgrade to a CXB series MSF 5000, but it's your baby.
Re: Micor Problem
I'm trying to remember which wire you jumper to 12v to bypass the circulator if it's UHF. The OP does not say what band he's working.
Re: Micor Problem
The repeater is on 462.575 mhz output, so yes its UHF. And the component that failed is the tripler. Exciter works fine its putting out 500mw good clean carrier.
Re: Micor Problem
guess i will replace the transistors in the tripler even though they tested ok, thanks for the assistance.
Re: Micor Problem
Another thing that was discovered is the control wire on the PA (yellow) of the micor reads .880volts on idle, and when keyed it jumps to around 10 volts for like a millisecond then back to.880volts. Dont think that is correct, i could replace the station control module don't know if they go bad or not but i do have a spare.
Re: Micor Problem
I think that's the wire I'm talking about. If it's part of three small wires down to the control shelf, jumper the yellow to 12 volts, and key the station. If you get steady power, it's the circulator going bad. Usually it's the 50 ohm load on the reflected power sensor has opened, and the protection circuit shuts down the PA.
Re: Micor Problem
Yeah i already troubleshooted that one,and its still staticy,,if i move my HT close to the exciter its crystal clear, but 2 feet away from the machine and its weak. I pulled the exciter and 1st bandpass filter out of the 'parts' machine lastnight, when i get a chance i see if either one of those is the culprit. What gets me is when the station first got weak (2 weeks ago) i pulled the tripler and repaired a cap inside of it and put it back in, and nothing, but if i put it in the 'parts' purc paging station it keyed fine full output,,so i robbed the power control board and the diamond shaped transistor that goes behind it and put it in the machine that went down. I also replaced antenna network, and PA, the only thing i didnt replace so far is the exciter itself and 1 st bandpass filter. I was going to replace the 'station control module' but my spare one is slighly different and i dont know if it will work, due to my 'parts'control module doesnt have 'exciter audio pot' and the one in the machine that failed does. Its keying and passing audio fine so i dont think thats it anyway. Its a shame this is a very well maintained machine, i even got the orginal computer print out for it when it was purchased back in the 80's of the jumper (s) and mudules and frequency it was set on. I wish i could figure this out, i got a manual but its for the 800mhz station not 450-470mhz stations, although they are similiar. I need to buy a micor test set.
Re: Micor Problem
Thanks for your help guys, i got it working again. I replaced the exciter and it took right off.I can hear the power supply draw on key up now never heard that before when i intially sat it up. I guess the exciter was working half power the whole time. I got the drive limiter set halfway up as the manual says not to turn ALL the way up, but the power set on the power control board is all the way up. Now i need to invest in a motorola micor test set for this thing. I really like the most about this machine is that EVERYTHING unplugs for ease of replacement how cool. Anyways, thanks for your help.