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I have a hi power VHF xtl 5000 that has worked perfect for 6 months. 2 days ago the tx audio is just a garbled mess on the receiving radio. Wouldn't tx on digital at all. Looking for someone who can suggest some simple tests or steer me to someone who works on these. Still sounds perfect through the PA. No post errors, all other radio functions are normal. Receive is perfect on both digital and analog..

Thanks for your time!!

BigJim

BigJim wrote:I have a hi power VHF xtl 5000 that has worked perfect for 6 months. 2 days ago the tx audio is just a garbled mess on the receiving radio. Wouldn't tx on digital at all. Looking for someone who can suggest some simple tests or steer me to someone who works on these. Still sounds perfect through the PA. No post errors, all other radio functions are normal. Receive is perfect on both digital and analog..

Thanks for your time!!

BigJim

Have you measured the actual TX frequency as compared to what has been programmed into the radio?

Have you measured the TX deviation as to whether it has been programmed to Narrow band modulation?

There are only a few things that can cause distorted TX audio. It's just trying to narrow down the cause of the TX audio distortion by making some measurements.

Jim

Sorry but I haven't measured anything yet, so that's of no help to you.

Radio is still in the vehicle as we are in the middle of harvest.

It's just seems strange to me it can work perfect on all channels then just not work the next day

I'll post more when it can be hooked to the service monitor.

Thank you, BJ

Alignment will most likely solve all your problems.

Strange thing,

Actual TX on programmed freq of 166.125 shows 166.133 on a cheap optoelectronics freq counter. Another freq of 166.000 shows 166.006

Various freqs across the full range (150-167) are mostly correct, some are not.

I reprogrammed 166.125 to 166.115 and now tx's on 166.123.

This will get me by until the end of harvest.. Then I need someone to fix it up right.. Anybody who works on these? Don't want to go moto if I don't have to, and I don't have a service manual for the XTL5000 yet.

Thanks, BJ

BigJim wrote:Strange thing,

Actual TX on programmed freq of 166.125 shows 166.133 on a cheap optoelectronics freq counter. Another freq of 166.000 shows 166.006

Various freqs across the full range (150-167) are mostly correct, some are not.

I reprogrammed 166.125 to 166.115 and now tx's on 166.123.

This will get me by until the end of harvest.. Then I need someone to fix it up right.. Anybody who works on these? Don't want to go moto if I don't have to, and I don't have a service manual for the XTL5000 yet.

Thanks, BJ

An alignment is most likely in order, I can perform that for you, just pm me when your ready.

BigJim wrote:I have a hi power VHF xtl 5000 that has worked perfect for 6 months. 2 days ago the tx audio is just a garbled mess on the receiving radio. Wouldn't tx on digital at all. Looking for someone who can suggest some simple tests or steer me to someone who works on these. Still sounds perfect through the PA. No post errors, all other radio functions are normal. Receive is perfect on both digital and analog..

Thanks for your time!!

BigJim

Hi power radios draw crap loads of current. Check ALL of your connections including grounds. Look at where you have your brick attached to for power. Any corrosion? Connection tight? Using a DC voltmeter, check voltage when radio is transmitting, preferably at the radio. If voltage is dropping much below 12.5 VDC, you can start to have problems.

If that checks out, program the radio to low power. Does the problem follow? Does the antenna present an acceptable VSWR or reflected power?

If you know your frequency counter is accurate, use the tuner program to align the reference oscillator on the test frequency but only after you vet out the issues I described above.

I ran the tests suggested. Did a very slight alignment on the reference oscillator. Freq shows good while running tuner. 166.12500 programmed shows 166.131470 on service monitor when keyed with mic. Shows the same on low power of 49W and high power at 96W. Known good radio shows 166.125059 on service monitor.

Awaiting suggestions,

Thanks James

BigJim wrote:I ran the tests suggested. Did a very slight alignment on the reference oscillator. Freq shows good while running tuner. 166.12500 programmed shows 166.131470 on service monitor when keyed with mic. Shows the same on low power of 49W and high power at 96W. Known good radio shows 166.125059 on service monitor.

Awaiting suggestions,

Thanks James

There is a very slight chance that the EEPROM has a problem with that channel (mode) position. I would try programming your desired channel frequency into another channel (mode) in the radio and see if that clears up your problem. If so, put some bogus channel into the bad position and program the control head to display "BAD CHANNEL" or something like that in the bad position.

Jim

Tried that, made a new personality, zone, and channel. No difference. Radio is changing all tx freqs by about +6.2khz

Really strange

BigJim wrote:Tried that, made a new personality, zone, and channel. No difference. Radio is changing all tx freqs by about +6.2khz

Really strange

Radio worked ok then wonked out all by itself? Odd that it worked then is changing by that 6.25 which is now a valid step.

Did you do anything like upgrade firmware or a different version of CPS? Can you post F/W and CPS versions?

Check this, in Zone Channel Assignment > Channels, what is the
Tx Opt Spacing set at?

Also, if radio is programned as talkaround, T/A frequencies are exactly 166.12500?

Lastly, do you get any kind of invalid field notice when you write the radio?

This really seems like your 166.125 isnt a valid step......

Channel spacing at 25.0khz on certain channels Reason for not being narrow is we work with a guy who has a bunch of old radios

Radio worked perfect when I left at midnight. Turned it off for a few hours, went back to work at 6:45AM and it was junk. The frequency change took place that night all by itself. Radio worked perfect for the 5 months I used it before that. There were no updates and it was never even hooked to a computer since I first programmed it in early March.

CPS R20.01.00
CODEPLUG 0024
FIRMWARE R20.50.07
TUNING R01.00.05
BOOTLOADER R07.00.00
DSP R19.50.01
UCM UNKNOWN
PSDT R04.00.00
NAUTILUS R06.00.00

Did you recheck the reference oscillator tuning to make sure it took the changes?
Is the receive off frequency as well? It might sound okay even if it's off... check on service monitor by varying generator freq and see where best receive is.

Reference oscillator took the changes. I even set it off from the test freq and tried that one time. That made no difference on how far off freq the radio transmitted from the programmed freq.

Receive is right according to my svc monitor.

BigJim wrote:Reference oscillator took the changes. I even set it off from the test freq and tried that one time. That made no difference on how far off freq the radio transmitted from the programmed freq.Receive is right according to my svc monitor.

So no matter where the Ref. Osc. warp is set the transmit frequency is off by the same amount? That setting works by using a DAC to generate a voltage that adjusts the 16.8MHz reference oscillator. I can't imagine what would make that work on receive but not transmit. Do you have MOL access? They have the manual on there, I think it's under the XTL2500 section though.

Have you looked at the output on a spectrum analyser to see if it's clean?
Have you inspected the circuit board to see if there is any spill, corrosion, or capacitor leakage?

You could try flashing the firmware.... maybe something got corrupted. Other than that it may need to take a trip to depot.

No MOL account. I can't do anymore so it has to go. I should have maybe stayed with Astro Spectras but wanted to try one of these and it did work really well when it worked.

I will post when it's fixed.

Thanks to everybody who helped with this.

BJ

jackhackett wrote:

BigJim wrote:Reference oscillator took the changes. I even set it off from the test freq and tried that one time. That made no difference on how far off freq the radio transmitted from the programmed freq.Receive is right according to my svc monitor.

So no matter where the Ref. Osc. warp is set the transmit frequency is off by the same amount? That setting works by using a DAC to generate a voltage that adjusts the 16.8MHz reference oscillator. I can't imagine what would make that work on receive but not transmit. Do you have MOL access? They have the manual on there, I think it's under the XTL2500 section though.

Have you looked at the output on a spectrum analyser to see if it's clean?
Have you inspected the circuit board to see if there is any spill, corrosion, or capacitor leakage?

You could try flashing the firmware.... maybe something got corrupted. Other than that it may need to take a trip to depot.

According to the tracking, the radio had been to the depot.LOL

An alignment squared this thing right up.....who would have thought? The radio literally failed every test except RX BER .

spectragod wrote: According to the tracking, the radio had been to the depot.LOL

Well that may explain it.

Not fixed after alignment. Problem remains the same. When txing it still adds about 6.2 kHz to every programmed frequency.

Anybody???

Who aligned it? I got the impression it was Spectragod, in which case I would think it was done correctly.

Did you do anything to it after it was aligned, like reprogramming it? If so, you may have a corrupted codeplug.

Other than that I don't think you're going to find any easy fix like checking a box in CPS. It sounds like a hardware or firmware problem.

It was Spectragod and I have no doubt it was aligned correctly. He didn't do an on air test so didn't catch the problem which shows up when it's keyed with the mic. He and I have discussed this and can't figure it out. I have no doubt he could find the problem if he had the unit.

When I received the unit back I tested it with his codeplug in it, same problem. I read and saved tuning and codeplug. I put my codeplug back in, no change. So as of now it's still not working correctly.

Ok, here's the skinny on this radio.

When I received it, I read the CP, first thing I notoced is a whored out
Flash and that it says it had been hit with depot.

I voiced checked it, radio was around 7Mhz off......wow!

I did a test on my aeroflex, the radio failed everything except the BER RX.

I aligned the radio, all came into spec.

I reprogrammed 2 channel for OTA testing with another mobile, I also programmed the
Frequency into my aeroflex 8800. And, I did voice check it over the air for both freq error
And modulation. I also listened to the audio quality on a vhf radio in the shop.

All worked flawlessly.

Fwiw, my service monitors were calibrated less than 6 months ago before we did a P25 migration,
So I know my equipment is spot on.

The OP told me that his Kenwood radios talks and listens just fine with this mobile now, I don't know
If it didn't before though.

He said his other moto gear doesn't RX the audio as well as the Kenwood, he also told me that in the
8 years (IIRC) his service monitor has never been calibrated.

Based on the above 2 items, I am leaning towards, his SM needs calibrated and his other equipment needs
An alignment performed.

This is all speculation on my part, I am fairly new at the two way field only being in it for 25 years. The old timer
I work with has been in it for 45 years, see why I say I'm a newbie?

At least eight years with no calibration?

Ugh.

This is why Moto requires us to have ours done yearly, service monitors, watt meters, spectrum analyzers, etc.

jackhackett wrote:At least eight years with no calibration?

Ugh.

This is why Moto requires us to have ours done yearly, service monitors, watt meters, spectrum analyzers, etc.

To his defense, he is not a radio shop, it would be hard for me to
Justify 200k worth of equipment at my house, being married and such. Wifey would look at that as shoes and purses she wasn't getting.

BigJim wrote:Not fixed after alignment. Problem remains the same. When txing it still adds about 6.2 kHz to every programmed frequency.

Anybody???

What are you using to say the radio is transmitting 6.2 KHz. off frequency? When was the last time that device was calibrated?

Something smells about this whole problem.

Jim

Marconi 2955. I know it hasn't been calibrated for at least 8 years.

I have tested 4 of my other Motorola radios and they vary from 11 to 62 hz off. The xtl is 6.2 kHz off, but when running the tuner program the reference oscillator shows dead on to a few hz off when you toggle it on and off a few times. One astro spectra I tested showed 166.124999 on a programmed freq of 166.12500 so I don't think the monitor is too far off. But I have no doubt it's off some, it's old.

Lets just put it this way.. I know the monitor is old and needs calibrated before I could argue the point. But the xtl sounds like crap on all my motorolas. But 1 Kenwood TK-5710 that I have doesn't receive it too bad. Maybe a sloppier receiver, I don't know. My ears plus a few sets of others verified this the day the xtl crapped out.

I have another xtl5000 arriving this week. When I test it we will see what it shows.

Bad reference oscillator. Replace the 16.8MHz oscillator in the radio and you'll probably be golden.

Thanks

Hope that is the solution.

Other XTL's did not get here Friday. Shipment delays due to weather,,Monday now.

d119 wrote:Bad reference oscillator. Replace the 16.8MHz oscillator in the radio and you'll probably be golden.

Going down the mother M road before, I'll speculate that this is a restricted part, so you get locked into a flat rate
Repair. It seems to be the game they play. I'll look in the service manual on Monday if things don't go to hell too bad.

I tested another xtl5000 and an xtl2500 that I received today.

FWIW the 5000 showed -69hz off the programmed freq. The 2500 showed -20hz off the programmed freq of 166.12500

Supposedly the 2500 was aligned shortly before I got it. They both sound great on receiving radios.

spectragod wrote:

d119 wrote:Bad reference oscillator. Replace the 16.8MHz oscillator in the radio and you'll probably be golden.

Going down the mother M road before, I'll speculate that this is a restricted part, so you get locked into a flat rate
Repair. It seems to be the game they play. I'll look in the service manual on Monday if things don't go to hell too bad.

Mother M lists the part, of course, it's not available....shocking. And, it's under a soldered on shield, more good times. There is the possibility that there is a problem upstream from the oscillator causing the issue, or.....even though it worked for 6 months, there is an issue with the flash the depot installed.

I'll know more when it shows up and I get to dissect it.

given that it sounds like the reference frequency alignment appears to have always worked doubt that the reference is bad.

interesting problem ..almost sounds like we are dropping an LSB in the divider ...hence the 6.25k difference

Was this problem ever resolved?

Not yet. I will post when it is. No further work has been done at this time.

Problem never was fixed. Radio is sitting on my office floor with 3 other good ones.

I might send it away to be fixed, don't know yet. I do know that it can't be fixed without digging deep into it.

Thanks to all who helped with this problem.

BigJim