1963 to 67 Radio Question

[Makda]

I have read that you must unhook the negative ground FIRST to remove a radio or rist damaging.
? #1 Why?
?# 2 What does it damage ?
I've always been taught to remove postive wire on a battery before doing any work??
I have 4 mid year radios I just bench tested two work great and two don't and I'd like to know what's up for the future.
Thank you
Makda ( That's grandson for Grampa )

 

[Tom Bryant]

If you remove the positive with the negative (ground) still connected you risk the possibility of a spark or arcing that can cause a battery explosion if there are gasses present from the battery vents. By disconnecting the neg ground first there is no chance of a spark when disconnecting the positive lead. You always want to interrupt the circuit by removing the ground first. With clocks, radio memories and engine computers all drawing a small amount of currant even with the key off you will see and often hear a spark when you connect a positive lead with the ground connected. That is a bad thing. I have seen batteries explode from this first hand and it isn't a pretty sight with your face only arms length from the battery.

This same arcing can fry electronic components in a radio, electronic ignition, engine computer ect. so it is always best practice to disconnect the negative cable before working on any electronic component on a car. Most of us have unplugged car radios and other components without any problem but once in a while it will bite you. But please never remove the the positive battery cable first again.

Tom

 

[kpic]

Ditto what Tom said..

Vehicles have a lot of things which are always "on;" this is why many cars drain the battery when parked for a while.

Even with a sealed battery, always remove the negative cable first. Many modern electronic devices are not tolerate at all of that spark. Sure, a lot of us have gotten away with it and often; yet there are many people who haven't.

You have to take them both off anyway.

 

[Vettehead Mikey]

I've always been taught to remove postive wire on a battery before doing any work??

If you have one hand on a wrench that's touching the positive wire and your other hand leaning on something metal like the engine or frame, you've provided a path for the current to flow through your body.

If the wrench were to touch something metal while it's on the positive terminal, now you've got a direct short.

Pretty scary.