Monitor Mod

What happens when StereoMan makes a commitment based on written spec’s only to find out that the written spec’s were wrong? Giving up would be the last choice for StereoMan! Always trying first to think outside the box, sometimes the answer turns out to be INside the box – literally.

My customer had two vans with overhead DVD monitors that were supposed to play through the vehicles’ FM radio, but there was no direct connection, and so the sound was of poor quality and outside broadcasts would sometimes interfere. A review of the monitor’s specifications led me to believe that the jacks on the side of the monitor were A/V output jacks. Why would there be input jacks? The unit had a built in DVD player and no speakers, so input jacks would be useless and useless.

So I gave my customer a quote, based on the written spec’s, to direct wire the monitors to the stereo, and we scheduled the work. But when I took down the first monitor, I saw the jacks on the side were marked “A/V input”. Daunted, but not defeated, I carried the unit back to the shop to see if I could figure out a way to wire an output. On the bench, I took the bottom cover off and there on the inside cover was a label, indicating that there WAS an output, or at least there was supposed to be an output.


















There was no 5-Pin Harness to be seen anywhere, but there were several 5-pin sockets where a 5-Pin harness might plug in. And a couple of them were white! Could one of them be CN1?



















I hooked up the monitor on my test bench and played a DVD while I poked around the white 5-pin sockets with my oscilloscope. Before long I had located the correct pins in the correct socket to derive the audio output. To each of the output pins I soldered the center lead of a short coax terminated with an RCA jack. To the ground pin I soldered a short wire …


















Next I soldered the wire to the coax shields …


















And after that, covered the ground connection with electrical tape …


















Lastly, to prevent undue stress on the wires I’d added, I hot-glued the assembly to the circuit board.


















I connected an RCA cable to my finished assembly, long enough to reach the back of the radio, and remounted the monitor overhead. When I played a DVD, the sweet, clear sound came through the vehicle’s speakers, just like I had planned. Success!


No Comments

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a comment

Security Code: