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I have a C7 800MHz. trunked Spectra that I have programmed, and correctly I might add, but I keep getting the 'out of range' message on the display.
I have already checked all of the personalities and frequencies associated with them, and everything is fine. I also double checked that the antenna was connected correctly, and it is.
So, if I have the radio programmed correctly, and the antenna is hooked up correctly, why would I be getting the 'out of range' message? Especially since I am only 2 miles from the TX antenna. My other Spectra is set up exactly the same way, and I receive traffic on it and usually get an RSSI reading of about 80.
Is the radio defunked?
PS: The radio RX's a signal just fine on the simplex channels programmed into it. Just not the trunked freq's.
Do you get an RSSI value when it's sitting there? Also, try programming the control channel as a simplex channel and see if you can hear it. Double check your system id is correct.
Are you sure that you don't have an old trunked system still programmed? If so, are you sure that your talk groups are pointed towards the right system?
OUT OF RANGE means the radio can not find the control channel, it scans several 'control channel' frequencies looking for the correct data patern, but if the receiver is not working correctly, it can not find the control channel.
SYNTH is probally OUT OF LOCK, ie; FAIL001. Note: I DID NOT say the VCO, they rarely fail. In a Spectra, there are two SYNTH's used in the receiver, either or both could be bad, just like Chato's C7 where both were bad.
Program each control channel as a conventional channel for testing and see if it gives the FAIL001, probally will. Or get out the O'scope and monitor the test points.
Alright. I programmed in the control channels as conventional/simplex channels and I heard absolutely nothing on them. I do not however get any error messages on the display (ie: FAIL001). I do still get the 'out of range' indicator though.
Where are these synths located, and does anyone have an accurate part number for these so I can get some local pricing for replacement?
All of the synthesizers are on the RF board - the big board under the radio. The smaller VCO plugs into that and usually has a full shield over it. On the top is the command board with the plug-in memory logic module (MLM), and the smaller shielded unit next to it is the front end filter.
Sounds like you need to get the unit up on the bench and make sure the receiver is working to spec with a conventional channel. You can also use the built-in test frequencies from the front panel which will save you all the programming effort. Basic and detailed service manuals will be required to go much further.
Also, have the transmitter checked as well. I'm not sure, but if the receiver hears the control channel, the radio might try to transmit to affiliate itself with the system, and if that fails, you might get an out-of-range display due to lack of affiliation. I don't know if trunking systems work this way, but it seems logical.
Well, I determined that the radio is TXing dead center on any given frequency. While it will TX on any given frequency, it will NOT receive anything , anywhere. The receive LED won't even light when I TX to it from only a few feet away. It's almost as if the receiver is dead. Could this be an internal antenna problem? If so, what do I need to look/test for?
Also, if the SYNTH(s) where bad, why am I NOT getting the FAIL 001 error on the display as stated previously in this tread?
The raio would still hear something with no antenna.
The RF board steers the VCO to operate on the proper frequencies. The VCO sends a signal to the preselector where it mixes with the incoming 800 MHz signal. The result (around 100 MHz) goes back through the cable behind the control head (on a dash-mount radio) and back into the RF board for demodulation. The service manual will have all the specific signal levels and frequencies.
If the mixer injection signal isn't making it to the preselector board, that will definitely give you a dead receiver.
On a 450 MHz radio, you unscrew the four preselector screws and the unit can be pulled out just a little. There's one coax coming from the power amp (RF input from the antenna jack), one going down to the VCO (mixer injection signal) and one coming out the front that goes back to the RF board (IF output). The cables are rather short. Make sure they're all fully seated. I'm assuming that the 800 MHz radio is similar, but I've never seen one.
If the mixer injection coax is plugged in, the next step would be to verify that it's actually there and on the right frequency. It might be about 100 MHz away from the incoming carrier frequency; the service manal has all the details and methods for testing. A general-purpose receiver or even a service monitor could be tuned to the injection frequency to verify its presence.
With a good signal generator, you might be able to send a signal into the RF board at the same frequency that would come out of the preselector's mixer. If the radio hears that, then that puts the problem back in the mixer or injection amplifier circuits. You just need the right equipment and have to attack this step-by-step.
Since you aren't getting a FAIL 001 error, and the transmitter IS working, we can probably rule out a VCO or synthesizer failure at this point.
Did this radio ever work, or was it dead when you got it? Who knows what a previous owner might have done. Maybe the preselector was removed and put back but never plugged in. Maybe the coax cables have been unplugged.
When I first got the radio and programmed it, it would receive sporadically. Sometimes it would RX all day, sometimes for just a few minutes, but once I turned it off and then back on, it would start working again.
However, when it DID receive, just before it would quit RXing it would start letting out short squelch bursts, and then would go quite.
Just FYI. I was in the alignment area of the RSS and I adjusted the oscillator warp from 70 to 55, and low and behold, I actually got it to RX my TX, loud and clear I might add, but it was only that one time, and did not work at that setting again. So, I rolled it back to the initial 70 an left it there.
Now. I think that you may be on to something when you talk about the mini coax lines. I was actually in there messing around giving everything a visual, and I may have inadvertently pulled the coax of the VCO mixer when I tried to pull the board up that the coax from the RF amp connects to. I'll go give it a look-see, and I'll get back to ya with my findings.
Since you were inside, and under the preselector, then you realize how short those coax cables really are. On my 450 MHz radio, I had to use a pair of needle-nose pliers to put it in. I think I did the mixer cable first, then lowered the rear of the board and plugged in the cable coming from the PA, then snaked the IF cable down through the hole in the front of the chassis and carefully pushed the board down into its cavity. Once it's down there, you really can't lift it back up to check if the cables are still plugged in.
Those Taiko-Denki connectors on the RF and mixer cables are usually pretty good, as long as they're fully inserted and you don't put any tension on them. Same cables and connectors are used in MaxTracs.
The IF output cable, that runs through the front of the radio and back into the RF board: there are two styles. One has an SMB male, the other has a Taiko-Denki connector. There's a very slight difference in lengths, and of course the parts book doesn't say which connector is on which cable. I had a 450 MHz preselector board given to me minus that cable, and had to order the SMB variety to fit my radio. Apparently the previous owner swapped preselector boards and found he had the wrong cable, so he removed the right one and never put one back onto the board. I'm only mentioning this incase someone else ever runs into it. This has no bearing on the current topic.
OK. Good and bad news. Good news first. I checked ALL of the mini coax cables, and they were all plugged in and seated correctly.
Now the bad news. That means that wasn't the problem, and we (I) still have the problem.
One thing though, when TX on a simplex channel, initially the transmission is very scratchy, that is until I mess with/wiggle the UHF connecter at the back of the radio. After giving it a wiggle or two the TX is very clear.
Could there be something wrong within the PA? Between the antenna connector and PA board? If so, what would I be looking for? Could this cause my symtoms of no reception?
The mini-UHF connectors are known to be a problem. The center female contact expands because some plugs are too big, or people put them in at an angle, or they just wear out. That would give you transmit problems, but the receiver should still hear stuff from several feet away even with no receive cable attached to the preselector.
Not much in the PA except the antenna switching diodes. Again, they wouldn't keep the receiver from hearing. They might make it insensitive, but not completely deaf.
Oh well, it was a nice try.
Time to dig out some advanced test equipment and the manual, or send it off to someone who has all that stuff.
I was so disgusted with the radio that I didn't power it on for a few days
Well, I decided to get the old laptop out and start tinkering with it again, so I powered the radio on and it's as if there was never anything wrong with it
It RX's and TX's just like it should
If anyone has any thoughts as to why this is, I'd love to hear em.
Otherwise, I will just enjoy the radio while it's working
Have you looked at the electrolytic capacitors at the RF-Board? They usually get bad after a few years, I have sucessfully changed them, and in most cases it does the trick!! FAIL001 and "Out of Range" problems disaper. I would recomend you to try changing them, before you do anything else!!
FAIL001 and "Out of Range" problems disaper. I would recomend you to try changing them, before you do anything else!!