# Knowledge regarding early 2000's Alpine in dash screen units with separate tuner box



## haromaster87 (Jan 20, 2012)

Hey everyone,

I'm working on an Alpine IVA-D300, one of the units that has a single din fold out screen in the dash that also has a DVD drive, then that is connected to a tuner box brain type unit which is mounted separately on a long harness.

I seem to have a total no power issue and I'm trying to figure out where my point(s) of failure is/are. I have to admit I've never worked with any mobile video capable equipment, so the brake signal wires are new to me. The previous owner of this unit wired in switches to the brake and parking brake wires, as a means to bypass it them. From what I understand, that should only affect certain functions and not overall power of the unit.

I have been trying to connect the unit minimally just to test for power. But before I dig deeper, I want to make sure I'm not still missing something regarding wiring. 

So, first question, the PO said the brain unit had been connected backwards, the switched 12v and constant 12v lead were hooked to a ground lead and the ground wire was then hooked to a positive lead due to a mix up. The 10A fuse in the constant 12v path popped, but the switched lead has no such protection. Would that have likely fried something like one of these brain units, or should the fuse have caught it? I don't know much about them or how sensitive they actually are or aren't.

If there's some hope from there, my next question would be, can the tuner/brain unit be tested for power from minimal connections? Naturally it has 12v constant, switched 12v and ground in the power harness. But just connecting those doesn't result in anything. I'm not sure if the brain unit requires signal from the in dash unit to power up.

My next concern is that I seem to be missing the DC to DC converter that plugs in a harness coming off the in dash unit. Are these required for the dash unit to show any signs of power? I would imagine it would, but I just want to make sure.

If anyone has an idea about any of those questions, that might help me to get a direction on this thing. Thanks for any help!


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## Sine Swept (Sep 3, 2010)

If it has a brain, likely everything needs to be hooked up for it to power on. Also a missing DC/DC converter will also be an issue for powering on the unit. 

I recall a friend getting me to test a monitor portion of a similar unit and sure as **** no power without the main brain.


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## haromaster87 (Jan 20, 2012)

Thanks a bunch for the info. I had a feeling the DC/DC converter is keeping the dash unit from turning on. And I suspected the dash unit needs signal from the brain to do anything since it seems mostly passive.

I guess now I just have to figure out the likelihood of the brain being fried after the mishap. I did replace the fuse in the harness fuse holder and confirmed 12v was making it to the plug pins for ground and constant/switched positive leads.


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