UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Vintage 70's 'Realistic' car radio wiring

'LIVEWIRE?' · 3rd Aug 2018, 11:28 am

What is printed on the label attached to that black wire? It seems odd to use black for a wire which will be at +12vDC when the radio is switched on, but a quick check with a multimeter set to a low ohms range will establish the wire's function. If it is common with the red wire with the radio switched on, then it is indeed a switched +12v supply line for an Automatic or electronic aerial, or maybe the trigger (switching) line for an external Booster amplifier. This check should be carried out without power applied to the stereo. Alternatively it can be done with a +12v supply connected, but without anything connected to the black wire, by using a meter set to DC volts ( a 25 or 30V F.S.D. range is best in this case. Either an analogue or digital meter can be used for these ckecks.

3rd Aug 2018, 11:28 am	#3
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Vintage 70's 'Realistic' car radio wiring What is printed on the label attached to that black wire? It seems odd to use black for a wire which will be at +12vDC when the radio is switched on, but a quick check with a multimeter set to a low ohms range will establish the wire's function. If it is common with the red wire with the radio switched on, then it is indeed a switched +12v supply line for an Automatic or electronic aerial, or maybe the trigger (switching) line for an external Booster amplifier. This check should be carried out without power applied to the stereo. Alternatively it can be done with a +12v supply connected, but without anything connected to the black wire, by using a meter set to DC volts ( a 25 or 30V F.S.D. range is best in this case. Either an analogue or digital meter can be used for these ckecks.