Motorola Spectra Question

[yardbirdjr]

Hello All!

I have two Spectra's mounted in my Explorer Sport and they work great, except for one small problem.

I am having volume problems.

I can get in the truck and the radios will be at low volume and the next time they will be a high volume.

They adjust in volume everytime I get in my vehicle. I do not touch the volume they adjust themselves.

I was just wandering if I need to change something in the programming, or if the audio circuits are abount to go out it the radios.

Any help would greatly be appreciated

David

[Jim202]

First of all, it might help if you provide some details. We are not mind readers here.

What type of control head are you using on these radios?

Are these radios front mount or trunk mount packages?

Have you replaced the capacitors in both of the radios?

Jim

Hello All!

I have two Spectra's mounted in my Explorer Sport and they work great, except for one small problem.

I am having volume problems.

I can get in the truck and the radios will be at low volume and the next time they will be a high volume.

They adjust in volume everytime I get in my vehicle. I do not touch the volume they adjust themselves.

I was just wandering if I need to change something in the programming, or if the audio circuits are abount to go out it the radios.

Any help would greatly be appreciated

David

[Bill_G]

The minimum volumes may be set high. Check the programming under Radio Wide for min vol value.

[Will]

If the Spectras are A5 or A7 this could be a problem in the control heads. We have seen that happen here.

[yardbirdjr]

To claify some of the questions.

They are 45 watt A-9 trunk mount units.

They receive great, the volume is the only issue. I have a few other Spectras that need the caps replaced, but that is another issue.

These Spectras work great and have never had the caps replaced.

Just like yesterday I got it the truck and my neighboring county dispatched a medical call and the tones went out they about busted my ear drums they were so loud.

This morning when I was coming to work the same county dispatch another call and the tones were so low that I could barely make out what was said.

I have not touched or adjusted anything on the radio.

I hope this clears some things up

[Jim202]

You probably are using the HCN1073x or 1033x heads. These are also prone to the same capacitor failure as the
radios. They bear a look at to see what is going on.

I would also pull the head apart and look at the push switch buttons and their membrane contacts under them.
I have seen all sorts of stuff spilled on the heads and it either gums up the switch or messes up the contacts
with the membrane. If you use a cotton swab and some alcohol, you can clean the contact on the membrane.

The front face plate and buttons can be cleaned with an old tooth brush and some soapy water. Don't use too
much effort on the face of the buttons, as the lettering is a little tender and you can take it off.

The reason I am leaning towards the head for the volume level settings, is that it controls the audio level and
not the radio. There is a chance that you have a flaky cable connection between the head and the radio. If
you take a couple of minutes and do the off and on routine with the control cable, this will clean those connections.
Need to do both the radio and the control head end of the cable.

As a last comment, the 4 capacitors on the control board that need to be replaced are all in the audio section.
If they have leaked enough, they can cause all sorts of audio problems. It may be from distorted audio at high
volume levels (audio seems low so you crank up the volume setting). The normal setting for the volume should be
someplace in the 8 to 12 setting. If you are on the high number side and still have low audio, I suspect your
caps are causing the problem. The radio in my wife's car had the audio go away all together. Was listening to
a conversation and it just went dead. Found the large cap in the audio section lost contact to the circuit board
on one end.

Pull the radio and look on the control board. Locate the large IC with the 15 pins that come out of it and go to
the circuit board. It is held down with one of the board mounting screws right on the side middle. The 4 caps you
need to look at are between this IC and the cover for the MLM board. There will be the large 10mf at 50 volts and
the 3 smaller ones that are 10mf at 16 volts.

If you look around these caps, you will see some dark crud and probably discoloration of the solder connections
and the land masking. They are not easy to replace without a hot air soldering tool. You can use a small tip iron,
but it is not easy. Make sure you wash the board off with a good cleaner to neutralize the chemical from the caps.
It is easier if you remove the board right out of the radio for these repairs.

Hope this helps in pointing you to locating your problem.

Jim

To claify some of the questions.

They are 45 watt A-9 trunk mount units.

They receive great, the volume is the only issue. I have a few other Spectras that need the caps replaced, but that is another issue.

These Spectras work great and have never had the caps replaced.

Just like yesterday I got it the truck and my neighboring county dispatched a medical call and the tones went out they about busted my ear drums they were so loud.

This morning when I was coming to work the same county dispatch another call and the tones were so low that I could barely make out what was said.

I have not touched or adjusted anything on the radio.

I hope this clears some things up

[Bill_G]

I use an LED flashlight. Does a good job of finding corroded solder joints around the caps that are just starting to fail, but haven't leaked enough to leave a stain on the solder resist yet. Good joints are very shiny and reflect well. Corroded joints are dull with zero reflection. If I find one bad cap, I replace them all.

[Jim202]

Here is a photo of a control board with some cap leakage.



Jim

[Will]

Here is a photo of a control board with some cap leakage.
Jim

Jim, that one will have a pop in the speaker. Damage already started.

[Bill_G]

I've seen much worse. It wicks down the plated eyelets and damages both sides as well as eats the eyelet. It eats away the pads to the tant bypass caps on the audio output causing high current which wipes out the PA module. Nothing but fun to repair.

[Will]

To claify some of the questions.

They are 45 watt A-9 trunk mount units.

They receive great, the volume is the only issue.

I have not touched or adjusted anything on the radio.

Did you make sure the Green wire from the control head end of the control cable and the main Red power stays connected to the battery directly. This will keep the Volume setting which is in the X9000 control head stored when the radio is turned off.