User:Kmashaye5220/enes100/myWork2

Write problem/project Goal
1.Repairing an ATX power supply, which is already converted to a LAB one, but it does not work

My First Task
I am going to consider all possibilities that caused the power supply to be broken. I plugged in the power supply and observed that its fan does not work. I checked binding posts output voltage by a multimeter, but I saw that voltage of all binding posts are zero. There is no output. I took a video and explained the issue.

The video of the broken power supply

Possible issues:

1. one of the stripped wires, has touched the case, other wires, other connections or parts of the power supply, so the system goes to protection mode.

2. One wires has damaged in somewhere and has touched the case or other parts.

3. One of the original parts of the power supply, such as Capacitors, resistors, transformer,etc, has burned up.

Possible solutions:

1 & 2. Opening up the power; finding the stripped wire or the damaged part of a wire which has touched other parts of the power; disconnect it from that part; connect it to its proper connection and cover it by electrical tape or heating shrink.

3. I hope that none of the power supply's parts has burned up, because finding and replacing the burned part is so difficult and, it is not economically valuable. If the power supply is burned up, the best solution is to buy another power supply!

Summary of actual work over first weekend
My teammate and I opened up the power supply. I tested output voltages of the wires. The did not have any voltage. I checked the connection of the green and black wire. That was okay. We realized the the issue is bigger than we thought before. We tried to trace the input voltage and to figure out where the voltage is leaking, but it was so complicated and finally we gave up.

We got to convert more ATX power supply to LAB ones, so I took a power supply from a computer. I opened it up. I drilled 5 holes for binding posts. Then, I took anything I needed home. At home, I connected a red and a black wire to a 5 ohm power resistor. I connected all same color wires to each other, and I connected the green wire and a black wire to the switch. I attached binding posts to the holes. I connected all wires to their binding posts. Finally, I tested the power supply.

Week1 Narrative
In Class- My teammate and I opened up the power supply. I tested all output wires' voltages, red, orange, and yellow, but they did not have any voltage. I was skeptical about their wires, so I tested their voltage from the points that they were connected to the power's board. The result was same. I, also, checked the connection of the green and the black wire. The connection was perfect. Finally, we realized that the issue is more complicated than we thought it is. We started to trace the input voltage. we tested the voltage that comes to the power and then to its switch by multimeter. the voltage was 120 volt. Then, we followed the wires from switch to the board. I measured the voltage again. It was 120 volt. No voltage leak. After that, we tried to follow the voltage trace again, but it goes to something that I guess it is a transformer. We are not familiar with a transformer structure, so ,actually, we gave up. Troubleshooting a complicated ATX power supply needs lots of information and skills.

My Second Task
I should solder all connection and cover all stripped wires and connections by shrink tube. And the power supply will be ready!

Also, I guess I should convert another power supply.

Summary of actual work over second weekend
I labeled binding posts with their output voltage. After that, I soldered all binding posts to wires. Then, I covered them be electrical tape. After that, I soldered the green and the black wire to the switch and taped them tightly. Next, I placed the switch into its hole and closed the power supply carefully. Finally, I tested the power supply. It works perfectly.

Also,I got to make a test protocol for the power supply. For doing so, I made a simple circuit with the power supply, a 1.5 ohm power resistor, and a multimeter. And I measured currents with different voltages of the power supply. The results follows the formula V=R.I. I made a table of results.

In addition, I got to test a manufactured power supply which has been recently purchased for the class. I made a circuit same as above. And, I changed the voltage and observed how current relatively changed. Also, I realized that the power resistor got too hot when the current increased.

Week2 Narrative
I typed and printed voltage labels and stuck them below their proper binding posts.

Here is a video which shows how current increases when voltage increases. This video was taken a few minutes after running the circuit, so the resistor had gotten even hotter; therefore, as shown, the maximum current had decreased compared to a few moments before.

The Manufactured LAB Power Supply

My Third task
I should make two LAB power supply with these two boards:

Summary of actual work over third weekend
I measured the output voltage of the board #1, the smaller board, and I saw that it produced 27 volt and 5 volt. Also, I realized that when I unplugged that had still voltage, so I connected a power resistor to the white wire, 5 volt, and a black wire in order to discharge capacitors, but a small parts of the board- I guess a resistor- started to making smokes, so I unplugged it quickly. After that, when I plugged it again, I figured out the board does not produce power. It was burned up. Therefore, I cut off its power cable for using in the other board. I connected the power cable to the board #2 and measured its output voltage. It produces 5 and 1.2 volt. I need to make a box for it.

Week3 Narrative
First, I stripped all wires of the board #1. I has 8 wires; 2 blacks, 2 reds, and 4 whites. Then, I plugged it in and measured the output voltages. As usual, blacks are ground. I found out that reds have 27 volt. Also, the 3 white wires next to reds have 27 volt and the last white has 5 volt. Because I had already gotten 27 volt, I cut off those white wires which produced 27 volt. Therefore, I have 2 black wires, 2 red wires and a white wire.

Finally, I plugged in the circuit and tested the output voltages again. This board produces 1.2 and 5 volt. It was written on the board that it can produces 15, 24, and 5 volt, but in fact it does not. Probably, some parts of the board had been damaged, so it is not efficient as it has to be.

My Fourth task
I am going to make a box for the board, so it will be usable in LAB as a power supply.

Summary of actual work over fourth weekend
I got a spaghetti carton, and I put thick pieces of cardboard inside it to support its sides and make them stronger. I fixed the board on a cardboard and fixed it into the carton. I made holes for power cable, switch, and 3 binding posts. I placed them into their holes. Finally, I wrapped the carton by Aluminum foil and tested the binding posts voltages. They perfectly work. After that, I wrapped the carton by clear tape because Aluminum foil can easily be torn apart. Then, I printed and attached labels, which show the voltage of each binding posts, below them.

Week4 Narrative
I found a spaghetti carton. I put 4 pieces of cardboard parallel to each side of the carton and glued them in order to make the carton stronger. On one of those pieces of cardboard I screwed the board.