Friday, August 4, 2017

E470i LED Back-lit TV Repair

I picked up a 47 inch LCD TV with LED back-light that was no longer working.  I discovered that these LED back-lit TVs have the LED's wired in series and that eventually one opens up and the lights go out.

To dissemble the TV start by removing the back cover.  Then remove the metal cover in the foreground of the next picture it covers the LCD Connectors.

The cables need to be un-taped before they can be disconnected.  There is a black lock that flips out to release the cables.
Then remove the front bezel.  Besides lots of screws on all four sides there are some tabs across the bottom as can be seen in the front center of this picture.

Then there are several catches that will need to be unhooked.

The screen lifts out, being careful about the ribbon cables that are still connected to it.  Then there are four metal strips that hold the back-light filters in place.  There is a solid plastic filter and three flexible filters that will fall out if you are not careful.  Be careful to keep them in the right order but set them somewhere out of the way.
 Next is to remove the last layer covering the LED strips.  You will need to remove the pins that hold the plastic back and control the spacing to the front.  Two of them are under the power supply board.
 They are removed by pinching them with needle nose pliers on the back side.

Now to remove and test the LED strips.  They can be carefully pealed up with a flat blade screwdriver.  I used my fingernails to get underneath them to start the process.  Each strip has 4 or 5 three volt LED's (12 to 15 volts).  You can use two old 9 volt batteries to test them.  There should be a 100 ohm resistor in series with the batteries.  The end strips are tested by applying power to the test points near the connector.  The middle strips are tested the same way but you will need to short out the opposite end connector.

You will likely find 2 dead strips and maybe some dead LED's as well.  I actually broke one LED strip in the process of removing it.
Once you have the LED strips replacements you can test them out by removing the power distribution bad and testing them out like in the following picture before reassembling everything.  Remember that there are two sets of LED strips.

Here is a video on testing LED strops with 9 volt batteries:

HHR Head Gasket Repair

Update - After two months the car lost 2 quarts of antifreeze so I am trying another solution.  To be honest I did not follow the K&W directions completely.  Like you cannot leave the thermostat out of an HHR or it will leak badly.  See

My HHR overheated at a red light.  With the heat on I was able to get the temperature down to 235 degrees.  I added a gallon of water but two days later it needed more water.  Then I noticed that it was leaving puddles of water in the driveway under the exhaust pipe and spraying water 2 feet out from the tail pipe.  Then I saw the water bubbling in the radiator cap.  Is that absolute proof that the head gasket is blown?  After some praying and searching I used K&W Head Gasket Repair and now it is running fine again.

The directions require that you drain the radiator first and fill it with water.  Finding he drain in the HHR is next to impossible.  You cannot see it from above or below.  If you pull back the radiator plastic cover on the left side you might see one white plastic ear.  It is barely reachable but it can be removed.  

This video shows the bubbling.

The thermostat is also next to impossible to reach.  You will need a 10 mm socket and several extensions to get to the bolts.  You cannot leave the thermostat out as it will leak.  The seal is part of the thermostat.  But opening it up makes it easier to flush the cooling system.

After running the car for a while you once again drain everything and refill the cooling system. I did not think it was fixed because it was still running over 210 degrees.  However the radiator cap now had a seal when you try to open it.  Over the next few days of running the temperature slowly came back down to normal 196 degrees.

These cars run hotter than normal because the thermostat is on the return line from the radiator.  If the radiator offers 16 degrees of cooling then a 180 degree thermostat will allow the water to run at 196 degrees.  It gets even hotter while sitting still because the radiator fan does not come on until it reaches about 220 degrees.

Wednesday, August 2, 2017

FlameWheel F-450 with KK5.5 Controller one ESC went up in smoke!

I was flying my F-450 this time with a KK5.5 Flight Controller and one of the ESC's went up in smoke.  This is what the guts of the ESC looked like afterwards.

Here is the video.  I am still learning how to fly this thing.  It takes lots of practice (and crashes).