I though we had a few installer here and I wanted to post a question. OG Alpine TDM7534 Head unit: Unit has no ground wire out of the harness so on the bench I hooked a battery charger Neg clamp to chassis and 12V+ to the yellow lead marked ...12V in. Set the charger output to 2A manual and got nothing...I then found an unmarked black wire and used that for a ground (not even on the wiring diagram!) still nothing. I even tried to jump the red ignition power feed to 12V and jack. Any tricks to get one of these lit up on a bench? 15A blade fuse is still intact on yellow power feed but feed goes through a large black box. Is that an RF choke or something? I did get 12V on DMM at the clamps.