Microwave oven repair. Microwave oven keypad modification and repair. This video is about the repair of the Daewoo microwave oven front panel keypad repair and modification. The model is KOR-6L6BDSL This could from any company and manufacturer. Now a days the Chinese manufactured such items have a very bad service life. They become defective with an year. Problem with these units is their keypad go defective and then they refuse to do any function. I repaired a unit before also and the video is there on my other channel Learningzone. The link for that video I will include in the description section below. You must have to watch that video if you have intention to learn this job or work. In this video I will provide some necessary information but not all due to length limitation of the video. I am encouraging you to repair such a problem yourself. Anyhow if you can’t do such a job yourself, I am offering my services to do it for you. You would need to open two cable plugs and one screw to detach it from your microwave oven. First we would have to disconnect the control PCB from this front assembly by opening three screws. This unit had been sent to me by Mr. Nasar Ullah from Mardan. Then you should have to open the key pad connector and remove the keypad ribbon from the main PCB. We will detach this keypad connector and will solder pins instead of this connector. The owner had tried to repair it by soldering the joints but failed as this was not a dry solder or loose soldering job. Instead it was a keypad defect. I will test the board in the end of this video and then will send it back to the owner after testing and confirming. Then detach the front panel plastic sheet as it glued to the front panel. The keypad is glued to the front panel plastic sheet. The keypad is of very odd make. You can see it is made in two plastic layers and circuit on them. Next we will mark all key positions and center of keys using a sharp object like a needle, a knife or anything similar. Now grab your drill machine and fix an appropriate size drill on it. Then drill holes for the micro switched. The drill size should match the micro switches size. Now drill holes for all micro switches on the marked positions. During drilling you should have to hold the panel otherwise it can be rotated as you watched in the video. We will do all holes in this manner. Also the holes we will clean latter on before fixation of switches. Now we will take a ZD board and will cut it according to the size of the panel and holes for switches. Then we will make holes for all switches and other items in the board. We will populate the 12 switches on the board and then will interconnect them according to circuit. I made all 12 holes in the front panel for switches. The ZD board is also populated with micro switches according to the holes created. This board will be fixes on the front panel as shown in the video. When everything will be fixed and the front plastic sheet also, the front panel will look like the original. There will be no modification seen from outside. The main control board we will fix on the same place as it was. Then latter on will fix all screws to fix the main board in. The way will be the underneath will be the keypad board and on the top of that will be the main control board. And the cables from the switches will be interconnected on the main board connector. The switches wiring and interconnection is a very big process and very time consuming to solder all switches in a sequence. I will not record that to reduce time. Now the circuit had been populated and the wiring with the switches had been done. Now the importance thing is I would have to show you is the connection between two boards. The wiring seems to be very complex but it is not that complex. If you understand once, it is easy. This is the wiring connector circuit diagram. I will post this schematic diagram on my blog post. This diagram is needed to the owner of the machine. So I will ship this schematic also along with the front panel after testing. Now we will test this circuit for proper function. The owner didn’t sent the whole machine but the front panel only. So we will test it for function. We would have to solder two wires for Line and Neutral which is mentioned on the PCB and also one can understand that these two connections are going to the power supply on the board. The third wire is relayed power to the cooling fan of the unit. Which we are not connecting at the moment. Now we are supplying 220V home AC power to the unit by plugging it in the line. The important item is a jumper must be fixed on the DOM door interlock. This is important to short the door interlock terminals with a small jumper wire to make this circuit to work. We are temporarily soldering a small jumper wire to complete this interlock. Latter on we will disconnect and remove this jumper after testing. Take care of yourself from line power. As we will connect the circuit with electricity to test it. Now we are powering up the circuit. Now the system is on. We will test our created keypad by applying some commands to it. We will see commands on the front panel sheet and will press the corresponding switch. As we have tested the system and found it working. The relay is also clicking in the circuit showing everything is ok and the circuit is ready to be fixed on the microwave oven. For further details must read the blog post on this video. I will mention its address in the description as well as in the comment section.