spectra consolette transmits until turned off HELP!!

radio64 · Post by **radio64** » Sun Mar 19, 2006 2:31 pm

OK, I'll admit I'm new at the consolette. I programmed the unit up and when I transmit with the desk mic, it continues to transmit (locked up?) until I cycle it off. Receive is great. I remembered reading something here on the boards, but can't find it now. Anybody able to help me fix this problem? What have I got wrong? unit supposedly has trc board, but I don't know where it is located. DEK / VIP are disabled / zeroed... Unit is L53KXM7174AM according to software (tag missing) Inside is a D43KXA7A4AK spectra. HELP!!! Thanks, Ben

RFguy · Post by **RFguy** » Sun Mar 19, 2006 10:06 pm

I have seen this happen if the RX/TX 600 ohm lines (tone remote control) are left unterminated. Try adding 600 ohm resistors (or something close like 560 of 620 ohm) accross the tone remote control pairs on the rear db25 jack.

radio64 · Post by **radio64** » Mon Mar 20, 2006 9:45 am

um, ok. What pins are the culprits (I don't have a manual) Thanks.

RFguy · Post by **RFguy** » Mon Mar 20, 2006 12:22 pm

J2 pins 1 and 16 for RX

J2 pins 3 and 11 for TX

Try a 620 ohm resitor across each of these pairs. It may help.

radio64 · Post by **radio64** » Tue Apr 25, 2006 1:40 pm

OK, the closest resister I could get in a pinch was 680 ohm. tried placing them in the positions and.....

when I transmitted, the spectra cycled off!

I took the resistors out and it now still cycles off everytime I press the transmit.

I didn't reprogram anything, and the only thing else I did was built a small jumper from the spectra t/r box to outside the case for ease of programming (I have spectra programming cable, the desktrac cable I built won't communicate for some reason) and put the cover on.

What am I doing wrong here? While I have time to tinker with it, I'd like to get the blasted thing working... help... Thanks, Ben

RFguy · Post by **RFguy** » Tue Apr 25, 2006 6:18 pm

What do you mean "cycled off".

What exactly happens?

radio64 · Post by **radio64** » Wed Apr 26, 2006 1:33 pm

it cycles off and turns back on. I hooked it up to an external PS, thinking the supply in the consolette may be weak, but my 40 amp supply went dim, and made a strange buzzing noise (had to shut the ps off, the radio stayed on that time) so, I'm thinking it is something in the radio itself that is drawing tons of juice. Kind of funny that I went from not stopping transmit to no transmit in a matter of a couple days... I'm going to pull the radio out and try it as a stand alone radio, which will rule that idea in or out... Ben

kcbooboo · Post by **kcbooboo** » Wed Apr 26, 2006 2:06 pm

If you have a programming cable attaching the Spectra to an unpowered RIB and turn the radio on, the RIB will load down the programming lines and the radio will do all sorts of strange things, such as cycle itself on and off, leading you to go looking for a bad power supply, bad ignition cable, low voltage, etc.

The real Motorola RIB can get its power from the Spectra if the SWB+ wire is present in your programming cable. Many clones do not have the components or the circuitry to get power externally. Use an AC adapter or put in a good (measured) 9V battery.

First rule of troubleshooting: if it broke after you did something, then UNDO all that you did to get it back to the state it was in when it was working. This includes removing home-made cables!

Bob M.

radio64 · Post by **radio64** » Wed Apr 26, 2006 2:45 pm

Yup, still same problem after the removal of the cable. I use only genuine Motorola RIB and the low / mid power cable is motorola, although I never transmit when the programming stuff is connected, always revert back to 'normal' before transmitting. I did try adding resistors across the tone remote pairs (that is when the problem cropped up, but continues even after removing them)

RKG · Post by **RKG** » Wed Apr 26, 2006 6:37 pm

As a guess, does the radio in this configuration need a jumper at the accessory plug to defeat the alarm function? Consult the installation manual.

radio64 · Post by **radio64** » Thu Apr 27, 2006 1:51 pm

Well, the short programming jumper has the jumper on the pins, but the option is disabled in the software. Doesn't transmit on it's own, like the emergency setting. It almost seems as if the PS is not kicking out enough juice, but my MFJ 45 amp supply should have enough power to do the job. Also - the channel I selected to transmit on is set for 'low' transmit power. I pulled the spectra out of the consolette, tried it as a stand alone, same problem. I'm still trying to figure this one out... Ben

kcbooboo · Post by **kcbooboo** » Thu Apr 27, 2006 2:14 pm

Unless there's a major short circuit inside the power amp, a D43 should draw at most 10 amps on transmit, so your 45A supply should have more than enough juice to get the job done. If the power was going low, the radio would cycle off and on when you transmitted, but I don't think that's happening. The emergency jumper would make it transmit when turned off, but I don't think that's happening either. You confirmed the last two items.

Yes, very strange indeed. I guess substitution is going to be required.

Can you unplug the wireline interface going to the radio? I would expect the Spectra to be stable in that condition.

Bob M.

radio64 · Post by **radio64** » Thu Apr 27, 2006 3:52 pm

Well, that is basically what is happening: when I transmit, the radio cycles off and turns back on (and I get one faint buzz from the dimly lit external PS) The PS onboard runs the same. I've got a great receiver, just craps out whan I transmit.

I tried a different spectra on both the onboard and external PS, same thing... I'm begining to think it is more than a simple t/r box problem. I guess I'll have to put the PS on the bench....

RKG · Post by **RKG** » Thu Apr 27, 2006 5:40 pm

Before ripping things apart, put a DVM on the power supply's output terminals and see what happens to voltage when you try to transmit.

Will · Post by **Will** » Thu Apr 27, 2006 10:39 pm

The D43 Spectra is a 60 watt radio and can draw 12 to 15 amps at 'full throttle' on the TX power setting.

I have seen some D43 spectras do 85 watts, but draw 15 amps.

Your power supplies could be going into overload due to the excess transmit current.

jim · Post by **jim** » Fri Apr 28, 2006 5:20 am

Sounds as is the PA (or pre-drivers) may be getting DC instead of RF on their base during transmit. This would cause the PA to provide a B+ to ground path during TX and draw hard current. Could also be an unwanted oscillation. Can you even measure any RF output on TX before it shuts down?

Disconnect the PA and see what the radio does on TX.

jackhackett · Post by **jackhackett** » Fri Apr 28, 2006 8:18 am

You say you tried another radio, same result... have you checked that the antenna isn't shorted or something? Try it on a dummy load.

Also, before hooking the radios up again I'd check those supplies, make sure they're putting out proper voltage, and if you've got some sort of non-radio load (a 12V lamp, approx 30W for example) check the voltage under load.

Also, anytime you're dealing with a spectra you should open the radio up and check for leaky electrolytic caps, there's one in the PA, and some on the command and RF boards.

radio64 · Post by **radio64** » Tue May 02, 2006 1:54 pm

OK, so the hardest solution is the one right in front of you! I checked the power supplies, checked the caps, went back and forth trying to figure what the problem could be. I connected a mag mount antenna to the unit for kicks and giggles (instead of the antenna from the monitor I happened to have laying around (which has the N connector)) and whay would you know: problem solved. I had too much reflected power! Being allegedly so smart in electronics, I could kick myself for that one! The blasted thing is running like a top now. Thanks for all the help guys, you helped put my brain back into gear (and I'll never make THAT mistake again!)

kcbooboo · Post by **kcbooboo** » Tue May 02, 2006 2:06 pm

Large amounts of RF floating around can do strange things. People used to get RF burns from operating on 20 meter sideband with poor grounds. Obviously the shielding inside the plastic consolette case isn't very good when the antenna is nearby.

But glad you got it all working properly now. Go forth and modify !

Bob M.

spectra consolette transmits until turned off HELP!!

spectra consolette transmits until turned off HELP!!

spectra consolette transmits until turned off!