Hot Becker Radio

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brucemillar

MB Enthusiast
Joined
Nov 18, 2010
Messages
8,661
Location
Next Door to Alice - 25 'kin years now
Car
C55 AMG Wagon - W124 300te 4matic Wagon - BMW 4.8is X5 E53 - SWB Pajero 3.5 V6 24v
Folks

My Becker Radio gets very hot when on. I do mean very hot. I have the radio out of the dash just now as I was attempting to diagnose a speaker fault (now fixed). I noticed that the metal on the radio itself is really hot almost too hot to hold. Is that normal? What could be the cause?

It is not blowing fuses and is playing okay. Oh it has the built in CD Nav with external nav antenna.
 
There's a lot of electronics in there, including a amp...that all generates heat, and it has to go somewhere. The chassis acts as a heatsink, you'll often find a small fan mounted on the back too.
 
There's a lot of electronics in there, including a amp...that all generates heat, and it has to go somewhere. The chassis acts as a heatsink, you'll often find a small fan mounted on the back too.

Thank you Doodle. That puts my mind at ease.
 
Folks

The issue I am trying to fix is my speakers are muted - as in no sound output - not the head unit muted.

My car originally had the rear speakers with the fader switch in the center console.

I now have no rear speakers.
I have removed the fader switch.

In removing the fader roller switch I just unplugged the switch from it's base and used thin wire to jumper across the switch base terminals (crude but it works) or it did work.

I now get sound from the fronts - Good. BUT... Every now and again it simply cuts out.

This seems (could be anecdotal) to happen when I fiddle with the fader switch base.
Am I better of just removing this and connecting the wires with solder and heat shrink?
 
https://forum.allaboutcircuits.com/threads/damaging-amps-with-wrong-impedance.93669/

Because older Mercs tend to be fitted with speakers with odd impedances and your wiring is non standard its possible there's a mismatch between speakers and amp/headunit. The result of this might well be the headunit running hot. This would normally be expected to be focussed at the output transistors but could be manifested anywhere from the unit power supply to the output circuitry.
 
Well it seems that it was a combination of previous bodged wiring and the fader switch.

As I am not using rear speakers I cut out and insulated the fader switch and wired the front speakers directly to the Euro connector then into the head unit.

All working and not getting very hot.

Thank you gents for your help.

Bruce

Sent from my iPhone using sausage fingers.
 

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