Radio Ga Ga

lil nicky

lil nicky

New Member
Hi Guys!

I need help. I've just bought a in line signal booster for my radio. Great I thought, I'll finally get some tunes in the car. Not so. Got in to plumb the thing in and the radio wouldn't come on. I've done a bit of poking about and there is no power getting to it. I've traced the power lead back to behind the switch panel above the radio when it disappears into the loom. Could anyone give me a hint as to where it goes and what fuse it connects to. I've checked the fuse box in the glove compartment and they are all fine. Alternatively, anyone suggest wheres a good place to tap into for a new live feed? :D
 
What happens pretty commonly is that the negative or earth side of the radio falls off and is not noticed because the radio continues to function getting it's negative supply from the aerial earth/braid from the coax. If your radio was working before the advent of your in line aerial booster this may be the culprit as the booster may not be feeding the negative thru to the radio.
On any radio installation it always pays to make sure you have good solid earth connection to the chassis of the radio and that there is a negative wire also going into the radio loom as this will help to eliminate static and interferance that is commonly experienced on car radio installations most especially on AM bands. If you felt it neccasary to also put a booster inline it would also pay to check out the radio aerial earth (where the aerial base attaches to the roof) as you need a good solid earth at this point for all of the above reasons.

Have a happy new year!!


graeme
 
I know the radios earth is good, I put a new one in when I fitted the radio about six months ago. I haven't used it much since due to poor reception hence the booster, but when I tested it prior to fitting the booster it was dead. I've tested the live feed and it's dead, so I need to know where it comes from so I can test the other end and check any fuses. ( I can't read schematics so have no idea which fuse it goes to!). It is a brown and purple wire which seems to be original.
 
Power could come off the ign switch or the light switch,or could be tapped into a permanent live wire.
Did it work only with ign on or all the time before?
You need to carefully trace the power wire and see where it leads.
Run a new power wire direct from the + on the batt and see if that works to test radio hasnt blown
 
Hi,

Turns out the both the radio and the old power supply had died, so I isolated the old supply, ran a new one and plumbed in a spare radio. And all was well. Until I decided to look at my 8 track player, which leads me nicely onto my next question; there is no aux port on the radio so I want to wire in the 8 track direct to the speakers, these being the same speakers that the radio uses. Is this ok or do I need a switch or something to do it?

Thanks as always,
 
Hi,

How this is done depends on the wiring output from the 8 track. If it has speaker wire outputsthen just joining the wires will cause backcurrent in the output of both devices. This may work but you'll probably find that the volume of both devices is about half what it should be and one device will probably be louder than the other.

You can get little mixer amps that could mix the signals. You could put an external switch in as you say.

If it has a line level output then it's possible to modify the radio to accept the signal. Easiest place is probably in the wiring to the volume button.

Rich.
 
OK - looks like now all stereos tend to have line outs they've stopped doing the mixer devices...

So that leaves you with a switch or altering the 8 track and radio to bypass the amp which is probably pretty involved.

Other option is to have 2 separate sets of speakers but that brings it's own set of problems of where to put them.

Rich.
 
Yep - or you may be able to get one switch to do both at once. i'll take a look in a minute.

Rich
 
there are 2 ways to do it,

1. modify your speaker out from your 8 track with a speaker line to RCA convertor (I build those) then tap into the radio volume control circuit.

2. get a double double throw relay (you may need a 4 pole double throw) and wire 8 track and radio speaker output thru it to 1 pair of speakers, connect the relay coil to the 8 track on off switch so that when the 8 track is turned on the speakers connect. When you turn the 8 track off the radio will be the default connection to your speakers. I have done this quite a few times in cars for when i run multiple radios, works a treat.

Graeme
 
2. get a double double throw relay (you may need a 4 pole double throw) and wire 8 track and radio speaker output thru it to 1 pair of speakers, connect the relay coil to the 8 track on off switch so that when the 8 track is turned on the speakers connect. When you turn the 8 track off the radio will be the default connection to your speakers. I have done this quite a few times in cars for when i run multiple radios, works a treat.
Click to expand...

I'd never have thought of that... That's pretty simple and at the same time ingenious!

Rich
 
fellas,

i need to keep it simple, elastictrickery just aint my bag. I follow the four switch thing, seems simple enough. wouldnt be shy at having a bash at the relay buisiness either. I guess to do that I'd have to take the lid off the 8 track?
 
Switches are easiest to understand!

The diodes wouldnt really work as they'd distort the signal. No current flows through a diode until it hits a certain voltage ( 0.7 i think?) So you'd lose half of the signal...


Rich.
 
The diode thing in its simplest form will not work as the diode will still conduct on the half cycles and will provide loading to the wanted signal and hence distortion, there are still issues with the other output stage. Possibly you could just bang both outputs together with little effect but it depends on the configuration of the 2 different output satges however whilst it will likely work OK, it is an in-elegant solution and technically not nice.

Graeme
 
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