Here is a little write up of my latest engi-nerd episode.\u00a0 Well my 2004 Nissan Murano car remote decided to stop working a few months ago.\u00a0 It was in my soccer back while it was raining (the same day of the LA marathon) and it seems to have gotten wet.\u00a0 Well I broke down and bought a new one from the dealer.\u00a0 I should have done my homework and bought one online as you can find them 60% than the Nissan deal.\u00a0 What a scam!\u00a0 So now that I have a good remote I’m determined to fix my old one.\u00a0 I figure I’m an EE, I should be able to fix this.<\/p>\n
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So first thing get my BK Precision 2707A digital multimeter<\/a> (DMM) and some things out of the garage.\u00a0 I come inside sit down to get going and the DMM won’t turn on.\u00a0 Ah, dead battery right?\u00a0 To change the battery you have to unscrew the back off.\u00a0 So I get a screw driver and replace the battery…nothing. \u00a0 I take it out and put it back in make sure that there is a good connection and again nothing.\u00a0 Next, I put it on the Connective Mode where is gives off an annoying sound if the two leads touch.\u00a0 Schreeze!!!! Well that’s interesting it appears to be on, but the screen doesn’t work. \u00a0 I love how all projects have scope creep.\u00a0 Well I fidget around with this and do some online searching to see if there are any similar issues. No luck.\u00a0\u00a0 I found out that the version of my DMM has been discontinued and the company will give me a $30 discount on a new one if I turn mine in.\u00a0 I figure I might as well tear into this to see if I can figure out what is wrong before I bite the bullet and guy a new one.\u00a0 It unscrews pretty easily and is a pretty simple board.\u00a0\u00a0 The interesting thing is the screen isn’t soldered onto the board.\u00a0 It has this funny silicon-metallic stand that the screen fits on.\u00a0 A plastic cover snaps on to the PWB and holds the screen and stand in place.\u00a0 After sliding this stand around I can see the screen display characters which means the problem is likely the stand to PWB connection was just off (I may have dropped the DMM a while back).\u00a0 So I snapped the screen cover on and using a small screw driver adjusted the silicon stand in place.\u00a0 Wa La! the screen works.<\/p>\n Now back to the real project.\u00a0 I did a quick check to ensure the battery is connected to PWB and nothing.\u00a0 Interestingly, the buttons don’t pass a connectivity check when I put the probes directly on it.\u00a0 So I then placed the PWB into the good remote to make sure that it wasn’t the little buttons.\u00a0 nothing.\u00a0 (not really sure how the little buttons work at this point, but I’ll try to stay focused).\u00a0 Now that the first couple of easy ideas have failed I think I’m onto more work.\u00a0 I’m going to take a picture of the PWB and mark all the connections and then check to see if it matches the good remote.\u00a0\u00a0 I’ll report back with an update after that is done.<\/p>\n Final Update:<\/em><\/p>\n Well I went through probing the PWB and drawing out all the connection points. Which actually didn’t take too long.<\/p>\n After going through it I realized that the Vcc (power) didn’t connect to the switches any longer.\u00a0 The two red circles should be connected, but they weren’t.\u00a0 The little holes are there to connect the traces on this side of the PWB to the other side.\u00a0\u00a0\u00a0 For some reason the connection from one side to the other wasn’t working.\u00a0 So that is an easy fix.\u00a0 I turned on my soldering iron and place two wires through the holes then soldered each side to the PWB.\u00a0 My soldering job is actually a pretty horrible job and think the tip on my soldering iron may need to be replaced.\u00a0 I think I’ll save that project for another time.<\/p>\n After I soldered in each wire I checked the connectivity again and it all seemed to check out.\u00a0 I then went out to my car and reprogrammed the car following these directions (found on this forum<\/a>):<\/p>\n![\"\"](\"https:\/\/bt.beerprojects.com\/wordpress\/wp-content\/uploads\/2011\/05\/Solder-Point-300x179.jpg\" "\\"Solder")
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