Spectra shuts down when cycling through modes

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kcbooboo
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Spectra shuts down when cycling through modes

Post by kcbooboo »

Spectra 12w 900 MHz radio. Has several conventional channels. When cycling through the various modes, it gets to one and the radio immediately turns off and back on again, only to come back at the "home" mode. It's the same power-cycling that happens at the conclusion of reading the codeplug.

I have a feeling that one of the mode entries is bad. This is happening to two radios that were cloned from the same codeplug. I don't know if it's also happening on a 3rd radio that received the same codeplug data.

It reminds me of some old remote-controlled Zenith TV sets of the 50s where the tuning knob went from channel 2 to 13, then off, then back to channel 2. But I don't think modern Motorola radios should be doing this.

Any suggestions?

Bob M.
metro121
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Post by metro121 »

You are correct to assume that you have a bad mode programmed.
Best way to cure the problem is to read the radio and delete all modes and start over.

What usually happens with the problem you are having is when modes and or systems are added, somewere along the line, aparticular mode or system dropped out and when you get to that mode, the radio will see it as mssing and restart.
Jim202
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Re: Spectra shuts down when cycling through modes

Post by Jim202 »

You didn't say if there was a possibillity that the radio might have a trunking personality in it. You also didn't say if you had this problem on the bench or in a vehicle.

If this was on the bench, by any chance is the +12 volts going low if the radio tries to key up? This low voltage on the supply will cause the radio to act this way if the transmitter tries to pull too much current from the bench supply. This low voltage will cause a computer reset, just like your turning the radio on for the first time.

Jim


kcbooboo wrote:Spectra 12w 900 MHz radio. Has several conventional channels. When cycling through the various modes, it gets to one and the radio immediately turns off and back on again, only to come back at the "home" mode. It's the same power-cycling that happens at the conclusion of reading the codeplug.

Any suggestions?

Bob M.
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kcbooboo
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Post by kcbooboo »

There's probably one trunking personality/mode in it, and I don't know if it was on a bench or mobile. I suspect a bench. There was no transmitting done or anything else that required a lot of current. Just pressing the mode switch to go through them, and it comes to one mode and just shuts off, then turns back on again. I don't know if it happens at the same mode all the time (I suspect it does).

A little more history. This is one of four radios in a group. One had some channels reprogrammed (successfully) and that codeplug was cloned to the other three. Of those three, two worked just fine. The last one would not transmit PL or DPL. In desperation, someone deleted ALL the conventional modes from it in preparation for entering them all in fresh. When the codeplug was written back, the radio got stuck in a FL 01/90 loop and could not be accessed (always busy). We ended up replacing the MLM and doing a lot of hex editing to get it back to where it is now. So there could be a problem with the trunking mode, as that would have been left untouched during the cloning operation (I doubt a system key file was available).

Thanks for the info, however.

Bob M.
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Post by RKG »

In theory, when you delete or insert modes in a Spectra, the RSS takes care of renumbering modes. I have seen occasions (admittedly rare), there the renumbering didn't work and you have either a skipped number, a number used twice, or a mode 0. The Spectra won't tolerate any of these conditions.

In the one instance that I remember more clearly than the others, fixing this wasn't all that easy, because the RSS didn't like the corruption either, and it dumped me a couple of times. I think my ultimate solution was a batch delete using the mode utility (which only works on the conventionals), but don't hold me to that because I don't remember all that well. I do know that eventually somehow we fixed the problem.
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kcbooboo
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Post by kcbooboo »

You'd think that the software would guarantee the validity of the data it's sending to the radio, and that the radio wouldn't just go belly up when sent something it can't completely understand due to a program fault.

This is why I want to be extremely careful when deleting modes and personalities, so I don't end up with bogus data.

I agree, the batch mode delete only works for conventional channels.

I do have system key files for the two sysids in the trunking modes, and it allows me to delete trunking stuff, so I'll do them one by one and hope nothing bad happens during the process.

Bob M.
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Post by RKG »

Codeplug error checking was in its infancy when the Spectra RSS was published. It is neither perfect nor as rigorous as with later packages.
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Post by Jim202 »

The only reason I brought up the question about the trunking mode is that if you go to the trunking mode, the radio should try and register on the system. This will cause the TX to key up several times looking for the system.

If the bench supply doesn't have the guts to supply the required current to hold the voltage up while the TX is trying to do it's thing, the supply voltage will drop and the radio will sense it. This causes the micro to do a reset and try to power up the radio all over again.

It is easy to measure the voltage with a meter and see if this is the source of your problem. If the voltage hangs in there at the 13 volts or so, then now it will force you to go looking into the RSS for problems with the different modes.

I would try to find a mode that it will power up in and stableize. Then go to another mode. It may take a number of trials, but you should be able to narrow it down. There is a possibility that there is a data mode causing problems.

Jim
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kcbooboo
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Post by kcbooboo »

Thanks. That makes a lot of sense. I don't know if my Spectra is trying to transmit as well; I haven't looked at the current meter when I turn it on. I do know it says it's out of range, or some such message, because I've only had it on a dummy load. Never saw that meter move either.

Anyway it's something to check for.

Bob M.
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phrawg
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Post by phrawg »

I agree on the probability of the radio trying to register. That
has thrown me more than once when I forgot to turn the current
limit back up after working on a portable radio. the register
xmit pulse is very fast and it is easy to miss on a current meter
especially a digital one that does not have time to integrate the reading
and display it during a fractional second burst of xmit. Phrawg
BBbzzzzz... ZAP.. GULP !!! ahhhh GOOD fly !
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kcbooboo
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Post by kcbooboo »

And I suppose it's also a good reason to put a dummy load on any radio on the bench before powering it up, just in case it decides to transmit into an infinite load. Probably won't hurt for the short duration, but what if you just happen to have your fingers near the antenna jack while working on a receive problem?

All my meters are analog but even they could miss a few millisecond blip.

Bob M.
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