We have a back-up monitor system in the RV. It haz 7″ black and white monitor built in to the dash fed by three cameras: one in the back, and one on each side of the motorhome. It automatically switches to the appropriate side camera when you flip the turn signal on. So we can keep an eye on the Jeep as it gets towed along behind us as we go down the road, and Richard can check his blind spots when he wants to change lanes. And, as the name suggests, it’s handy when you want to back-up.
But it died. Not a little bit. Completely. The monitor’s power light wouldn’t come on or anything. We checked the fuse panel and all the fuses were good. So we found a new one on line and ordered it. But they sent us an e-mail saying sorry, but we are sold out and the item is discontinued. BLARG!!!
So, against my better judgement I decide to try fixing it. Troubleshooting without a schematic is iffy at best. The first bit of good news was Richard found an in-line fuse blown. 🙂 I suspected a possible power surge had taken it out. I went to the closest auto parts store and bought a pack of fuses. It blew the new fuse right away. 😦
I opened up the monitor’s case and did what I was taught a looooong time ago: the first troublshooting step is to make a thorough visual inspection. Since it had blown the fuse as soon as I had turned it on, I suspected a short circuit and was looking for signs of excessive heat. And I found it! One of a pair of diodes looked like it had gotten very warm. I checked it with an ohmeter and it read a short. I desoldered it and looked it up on the web. It was a rectifier, which made sense, it appeared to be in a power supply. I found a nearby Radio Shack on the web and called them. The girl who answered the phone didn’t even know what a diode was. I had to spell it for her. 😦 I thought that if you worked in an electronics store you should at least know what electronics are. 🙄 I read the part number to her and she said they didn’t have any. I wasn’t real sure I believed her.
Today I went to Radio Shack and found a diode that wasn’t a perfect match, but close. I installed it and VOILA!!! the monitor works again!!! I was so happy!!