Electricals Again (Radio)

[mkb]

----- Original Message ----


From: Grant Lenahan <glenahan at vfemail.net>
To: mkb <mkb125 at yahoo.com>
Cc: quattro at audifans.com
Sent: Fri, October 15, 2010 12:50:25 PM
Subject: Re: Electricals Again (Radio)

These radios have two powered inputs - one that is always on, and one that is 
switched.

Some power is always present to maintain memory, etc.

When you turn the knob, or push the button, or whatever you do to turn it on, 
one of two things happens_

1. a switch on the knob shaft connects the full power to the amp/etc.
2. a relay closes and does the same (remember, there is supervisory power to run 

a relay)

I would guess the on/off/vol switch, or the relay, is kaput.  Buy a new one or 
have it repaired (probably cheaper to get a new/rebuilt one). Search the web, 
including ECS tuning, force 5 ( a lister i believe)

If you want to check your wiring further, measure from a solid ground to the 
input to the fuse. Measuring "across the fuse" brings into question what 
 potential the unpowered side is at. Is there a capacitor there with residual 
charge? Maybe.  Who knows. Dont measure there. Measure to a known ground 
potential.

Grant

>>>>>>>>>>>

OK, so I was able to locate a ground close to the fuse panel on the left hand 
side of the vehicle.

So when I measure from the input (red wire +30) to the ground I get about 
12.5V.  If I measure from the other terminal in the fuse i.e. the red/blue wire 
(going out I assume) to the ground point, I get about 1.6V.

I'm not sure what this means.  I would think the 12.5V is good.  Not sure about 
the 1.6V.  Any ideas, 'casue I'm not sure what I'm doing, but I'm getting to 
know more about this car, he/she/it or whatever it is at this point.

Thanks.

--
mohammed
99 a6 2.8q avant
97 1.8qta