This Flurping Dodge's radio.

[The Griff]

Ok, well I've had this truck a decent month or so now, and I've dealt with it's radio not working the whole time, and my boombox in the back seat doesn't get the best reception.

I bought it from my aunt who parked it after my uncle passed away about a year and a half ago, and I was told it worked when she parked the truck, and I have no reason to doubt her.

I've tried 3 different radios in this truck, the original tape-deck that it had, an Identical tape-deck from my Cummins, and an aftermarket CD player radio I had in my garage, none worked in it.

My next thought is that the wiring must be messed up, so I did some research and found the constant power wire, and ran a hot wire to the fuse panel, no luck. So then I try running a hot wire for the Key-on power, to the radio fuse in the fuse panel, no luck.
Later I found a little amber strobe light, like for a mail man or snow plow, and it needs 12 volts to work, so this becomes my "test light" and it lets me know that the constant power wire in the harness does have a constant 12 volts, interesting.
Then I try it on the key-on power wire in the harness, and sure enough it works too. So I decide to put everything back together in the hope that it might have just decided to start working, Nope, still dead.

The backlight comes on, and rarely the top bar of the third digit of the clock/station will light up, but rarely.


I don't get it. I really don't.

 

[Fordum]

Got an ohmmeter? First thing you do, very first thing you do next, is check the ohms between the center pin and the outside shield on the antenna cable. Should be infinite. If you get any reading at all, check the antenna.

Good possibility its shorted.

If no reading, check between the center pin and the antenna shaft. Should be a dead short.
But, even if its open, I would expect something from a local strong station. If the center pin is shorted to ground, you probably won't get a sound.

If the antenna checks out, put your ohmmeter across the speaker connections. Here you are not looking for a reading, but are listening for a pop from the speaker when you touch the meter to the wires.

If all else fails, check the radio ground, or run a temp ground wire to it.

 

[rampage]

If the antenna checks out, put your ohmmeter across the speaker connections. Here you are not looking for a reading, but are listening for a pop from the speaker when you touch the meter to the wires.

Actually you should only gets pop if you momentarily put something like a 1.5v battery across the speaker terminals. Your ohm meter should give you a 4 ohm reading for most car speakers.

 

[Fordum]

You should get the pop with the ohmmeter too, since it puts power to the circuit to test it.
Depending on the meter, it can be as high as 9 volts.
And the ohm reading will vary from speaker, since the ohms rating on the speaker is the impedance, not the static resistance.

 

[The Griff]

Thanks Fordum, now I just need to find a ohmmeter.

I did have an antenna splitter in the truck, where the CB goes through the radio antenna, and it worked decently, but now I use a rear bumper mounted 70 inch, so I pulled the splitter out and hooked the radio antenna right into the radio.

No change.

(the splitter was basically a box with a coax cable coming out one end, antenna cable out the other, and a spot to hook the actual antenna into)

 

[Fordum]

Yep, used those splitters before. They usually had an adjustment screw so that you could supposedly set the SWR on the CB side so that the truck radio antenna matched the impedance of the CB.
They were remarkable in that they were usually the worst of both worlds. But they did work.
It would be possible that the box shorted out and the CB broadcast went into the truck radio and blew out the front end.

But that would not have hurt the other radios you tried unless you ran it with them too.
If you can't get a meter on short notice, just use a powered test light to check to be sure the center pin is hooked to the antenna and that there is no direct short from the center pin to ground.
If the antenna is easy to get off, pull it and look at how the cable is attached. Some of them plug into the bottom of the antenna, and it might have just slipped out when you were moving the other end.
Plus, most of those cheap antenna cables are single strand in the center, and it might have broken or come unsoldered at the end when you were moving it.

 

[The Griff]

Well, like I said, I found an amber strobe light that is for a plow truck or something, and that worked as my test light, would that work?

Me and the splitter didn't really see eye to eye, so it has moved on, to my toolbox. Hey, I got it for free and decided I'd try it out.

On a slightly related note, I lost my last working vehicle mounted radio today, I got a free head unit from a friend of mine, and the 94 F250 had the only working radio, so I was going to try it there, it does, yay, but as I too it out, more specifically as I pulled out the antenna, the little collar piece stayed in the radio and the center pin came out, great.

Now 0/4 vehicles have working radios,
The Ford just lost it's.
Your hearing the blight of the Dodge.
the Blazer just plain doesn't have one.
and the other Dodge needs speakers.

 

[Fordum]

I suppose any kind of light would work for finding a broken wire or a total short. That cable would not handle 20 amps or so, but an amp or two would be fine.

If you can solder, those ends are not hard to put on. But as a temporary fix, you can try this:
If you have plenty of cable, cut back the outside insulation about an inch or more from the end. Slide the braid back over the outside insulation, exposing the inside. Look at the inside insulation. If its about the same size as the center pin, some are different sizes, then cut the center wire back about a little shorter than twice the center pin length.
Strip back the center wire insulation so that the insulation part is the same length as the center pin, and fold the wire back along it.
The center wire should not reach quite all the way back to the braid to prevent a possible short.

Then plug the cable in like it was a connector. If the braid folded back on the outside is not large enough to make a tight connection, double it back on its self.

Not the best of all ways, but it gets you music until you can get a replacement cable.
I have done this many times for other folks radios in the woods.

Again, check at the antenna end. If the cable plugs in there, then you can buy just a replacement cable at an electronics store.

DO NOT pull the cable out without tying a pull cord to it. Sometimes they are a huge pain to get back in place without taking more of the truck apart.

 

[The Griff]

I can solder, but finding where my soldering iron has gone would be a job in itself.

The Ford is in no big rush, it doesn't have insurance at the moment, and when it does, its my "GIT-SH1T-DONE" truck, 3/4 ton, 4wd, Diesel, 4.11 axles.

 

[rampage]

You should get the pop with the ohmmeter too, since it puts power to the circuit to test it.
Depending on the meter, it can be as high as 9 volts.
And the ohm reading will vary from speaker, since the ohms rating on the speaker is the impedance, not the static resistance.

Not to argue a moot point or be a d***, but if you're getting a pop and no sound (buzz) then your meter is testing using DC voltage with no AC component. At DC the voicecoil acts like a piece of wire (after a few milliseconds anyways) so it won't have any impedance (which is related to AC voltage), it's just resistive. And if your meter is able to sustain 9V at 4 ohms then you're sending over 2 amps DC through your speaker (not good!), that's over 20 watts.
Neither one of my meters (Fluke 8020A and Fluke 8021B) made a pop when I connected it to a speaker, but a 1.5V battery did. With no resistor load the terminals of my ohm meters each measured 1.2V DC , measuring a 100k ohm resistor the 'test' voltage was at 0.6V DC and measuring a 4 ohm resistor the 'test' voltage was unmeasureable, and none of the meter readings had an AC voltage component.
The resistance measured across the voicecoil was and should be within an ohm or two of what is labeled on the speaker. And just as a reminder, sustained DC voltage across a voicecoil can damage the speaker (i.e. clipping), which is why you use an amp that has more power than what the speakers are rated for.

 

[Fordum]

Well, there is your trouble, you used too good a meters........

That is why I said

Depending on the meter, it can be as high as 9 volts.

A top of the line meter, like your Fluke, or mine, or my B&K, is going to put out a very low voltage on ohms.
In fact, if you look, your meter may have two ohms settings. One regular, one a high voltage one usually marked by a diode symbol.

The reason for that, is because there is not usually enough voltage to forward bias a PN junction.
Thus you cannot reliably check diodes unless you use that setting.

I expected him to have one of the cheap meter movement types. Those will usually produce a pop, just like your battery did, for the same reason.

And, your 1.5v battery does not have a whole lot of AC component either, which is why you just got the pop like you said.
And I never expected him to just sit there holding the meter on the speaker. I wanted him to just listen for the pop to verify that he did not have a blown voice coil or bad wires.

 

[Fred_M1010]

An Ohmmeter doesn't put out voltage.
It puts out current, and then measures the voltage that the current generates going through the measured resistance.

And the current is usually in the range of uA-mA so there is no risk of damaging a speaker by hooking an ohmmeter to it.

 

[The Griff]

Well this thread seems to have been sufficiently de-railed, lol.

I'm sitting here reading this and I'm using a freaking strobe light.
The more I think about it, I do think I have an ohmmeter, but I have absolutely no clue as to where it went.

 

[prolinews]

I'm no electrician, but have had a radio issue before. It kept killing head units and not fuses on a stock setup put in a aftermarket same thing? I had a speaker wire that chaffed in a rear door loom along with the power window wire! I found by hooking up one speaker at a time.

 

[Fordum]

An Ohmmeter doesn't put out voltage.
It puts out current, and then measures the voltage that the current generates going through the measured resistance.

And the current is usually in the range of uA-mA so there is no risk of damaging a speaker by hooking an ohmmeter to it.

I........Got Nothing....

Glad thats cleared up then.

 

[Fordum]

Well this thread seems to have been sufficiently de-railed, lol.

I'm sitting here reading this and I'm using a freaking strobe light.
The more I think about it, I do think I have an ohmmeter, but I have absolutely no clue as to where it went.

Maybe not so much derailed as expanded.

Lets simplify.

If you got a 1.5 volt battery, rig a couple of wires to it, and touch them briefly across the disconnected speaker wires to see if you hear a "pop". If so, then hook the radio back up, except for the antenna.

Stick something conductive, like a thick piece of solid stranded copper wire, or a small screwdriver into the hole the center pin goes in. Not too far, just so it makes contact.
Don't let it touch the sides of the socket, or ground.
Put your finger on it, and vary the tuning knob with it set on AM to see if you hear anything.

 

[Blue85]

An ohmmeter does not put out "voltage". It's a current source. Many DMMs will have 2 different current levels available. You need more current to measure smaller resistances. The ohms measurement is a calculation based on the voltage measured while the current source is on. Of course it has different voltage ranges it uses in different resistance ranges. An ohmeter that makes an audible sound in anything but a tiny speaker is probably not safe to use on electronics.

As for impedance, resistance is one component, so even a resistor has impedance, it just doesn't have reactance. A 4 Ohm speaker typically has about 3 ohms of DC resistance, inherent to the long length of tiny wire the voice coil is wound with. Therefor, using an ohmmeter to check speaker wiring or speakers for an open circuit works fine. No need to listen.

 

[kennyw]

So, your saying that you get some back lights on the radio to come on, but it doesn't look like everything is fully powered? Digital display is not showing the clock or radio station read out?

 

[The Griff]

The backlight comes on when the truck's lights are on. But nothing else. It has constant 12v and key-on 12v.

 

[chesafreak]

What year is it? Is it an infinity system?

If so you have an amp under the glove box.. stupid expensive(its a speaker cable line in line out type set up). I just took mine out put in a aftermarket deck and crimped speaker connections together where the amp was.