Electricals Again (Radio)

[Grant Lenahan]

Why rule it out? It failed once, it failed again.  On my c4 i did this every 3 years until i took it apart and hard wired it.

Its a desin flaw.

Grant
On Oct 15, 2010, at 2:28 PM, mkb wrote:

> ----- 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
> 
>>>>>>>>>>>> 
> 
> Grant,
> 
> Thanks for the info.  Looking over the service history of this vehicle, I see 
> that the PO had replaced the radio because he was having the same issue, so I 
> think I can rule out that option for now.  I'd have to look at the circuit 
> diagram again to see whether there is a relay in play somewhere.
> 
> I know there is a known good ground point in the left A pillar wiring harness 
> close to the fuse panel.  I'll likely measure there.  Appreciate the info.
> 
> --
> mohammed
> 99 a6 2.8q avant
> 97 1.8qta
> 
> 
> 
> 
> 

Grant Lenahan
glenahan at vfemail.net