I'm having problems with a JVC KD-DV6201 head unit fitted in an Alfa
147. I had the unit installed and working fine, then one morning it
wouldn't power up.
I know that there is power getting to the head unit: If I press the
"disp" key on the front panel of the JVC the clock on the head unit
would illuminate for a few seconds, then go out.
It will also accept and reject discs without any problem. It just
won't turn on - with the ignition turned on or not.

I have a steering remote control fitted between the ISO connector and
the JVC - I've tried removing this, and connecting the ISO directly to
the head unit, but it makes no difference.
I've tried switching the red and yellow wires from the head unit -
battery vs. switched 12v - it made no difference.

The original Alfa head unit (a Blaupunkt) works fine - powers up when
I turn the ignition key.

The previous evening I had been trying to adjust the unit because it
was protruding from the cage, but wasn't aware of damaging anything.

I returned the JVC to the supplier (it's only 2 weeks old). They say
they tested it and found no problem - had it running "all afternoon" -
and returned it to me.

Could anyone offer any advice/suggestions?

On Mon, 07 Aug 2006 18:23:36 GMT, ITM
wrote:

I returned the JVC to the supplier (it's only 2 weeks old). They say
they tested it and found no problem - had it running "all afternoon" -
and returned it to me.

Could anyone offer any advice/suggestions?

Try connecting both power feeds from the head unit (red and yellow) to
the red cable temporarily. If this results in the JVC working with the
ignition on, you've blown the car fuse in the permanent live feed.

Jon
--
In-Car Express http://www.incarexpress.co.uk
Car Audio | Security | Multimedia | Navigation
Tel. 01223 301212 Fax. 0870 7484123

On Tue, 08 Aug 2006 10:36:20 +0100, In-Car Express
wrote:

On Mon, 07 Aug 2006 18:23:36 GMT, ITM
wrote:

I returned the JVC to the supplier (it's only 2 weeks old). They say
they tested it and found no problem - had it running "all afternoon" -
and returned it to me.

Could anyone offer any advice/suggestions?

Try connecting both power feeds from the head unit (red and yellow) to
the red cable temporarily. If this results in the JVC working with the
ignition on, you've blown the car fuse in the permanent live feed.

Jon

I've tried with both leads connected and get the same result in each
case. If I re-install the original Blaupunkt head unit it still works
fine - i.e. turns on and off with the ignition key. This presumably
indicates that the power feed is OK from the ignition switch?

The fact that the supplier found no fault with it indicates that the
problem is with the connections in this vehicle, but the fact that the
other head unit works fine eliminates alot of the potential causes.

???

On Tue, 08 Aug 2006 17:59:07 GMT, ITM
wrote:

The fact that the supplier found no fault with it indicates that the
problem is with the connections in this vehicle, but the fact that the
other head unit works fine eliminates alot of the potential causes.

The fact the OEM unit works should be completely ignored - all that
this tells you is that there is power somewhere on the car connector
as a lot of OEM units will work quite happily off a single supply
feed.

If the unit works out of the vehicle, then there are only really 3
possible causes - no ground, no permanent live or no ignition live.

Disconnect the wiring harness from the back of the radio, then measure
the red and yellow cables with a voltmeter. Both should have +12v
present with the ignition on. If either is missing, it's almost
certainly a blown fuse in the car.

Measure from the black wire to chassis ground with an ohmmeter. This
should read less than 1 ohm. If it doesn't, you'll need to run a new
ground lead to chassis ground.

With all of the above, the radio must be disconnected at the time,
otherwise you'll get false readings caused by the internal resistance
of the unit, or from voltage going to ground from the unit.

Jon
--
In-Car Express http://www.incarexpress.co.uk
Car Audio | Security | Multimedia | Navigation
Tel. 01223 301212 Fax. 0870 7484123