Rebirth of America, this is my era

Chapter 9 Game Over
When Ethan once again stepped into Evelyn's experimental base, what he saw was an empty table and a clean space. The neatly put away tools and the components piled in the corner seemed to be narrating the hard work of the owner, but the broom and dustpan lying casually were telling of the carelessness of the user.

Ethan bent down and put these things in place, but his obsessive-compulsive behavior made Evelyn shake her head.

"I left it there on purpose, because it's easier to pick up."

"But it's not beautiful." Ethan replied with a smile.

"Oh, fine, as long as you're happy."

Evelin sneered at this waste of time, and she was in a good mood and didn’t bother to argue with her brother.

He patted the table and brought everything back to the point.

"Ethan, circuit boards are actually very simple to make. The first step is to draw a circuit diagram."

"Since you haven't studied this aspect systematically, I will skip explaining this part for now. If you want to learn, I can teach you later. Now, I will use the circuit diagram I designed last night to make the board."

She shook the paper in her hand.

There are dense lines drawn on it.

"After you have the circuit diagram, the second step is to cut the copper clad board so that its size matches the size of the circuit board you want."

Perhaps it was because she had come to the field she was best at. At this moment, Evelin, standing in front of the operating table, looked confident.

She picked up a piece of copper-clad board that Ethan had just bought and said, "You'd better remember everything I'm going to say, because in the future, whenever we make circuit boards for small-scale objects like this, we'll use boards like this one. The board you're looking at now is called phenolic paper-based copper-clad board. It uses phenolic resin as a binder, wood pulp fiber paper as a reinforcing material, and a layer of copper foil on the surface."

As she spoke, she tapped the copper plate with her fingers.

That clear voice sounded like it was saying -

'I'm a good guy.'

"You'd better remember the specific dimensions. The total thickness of this board is 63 mils, and the copper foil thickness is 1.4 mils. This data is a near-perfect small circuit board data that countless engineers have personally measured."

"Because the greater the total thickness of the copper-clad board, the harder it is and the more difficult it is to process. The thinner the thickness, the softer it is and the easier it is to deform. What's more fatal is that at the same time, the heat resistance of the board will also become very poor."

"The thickness of the copper foil layer will affect the conductivity, heat resistance and anti-interference performance of the circuit board. The thicker the copper foil, the better the conductivity. The thinner the copper foil, the worse the conductivity. It is also prone to cracking and breaking."

To be honest, Ethan knew that rubbing the circuit board by hand might be troublesome, but he didn't expect it to be so troublesome.

For a small circuit board, the material selection alone requires careful consideration?

This was an area he had never imagined.

However, the clearer Evelin’s description was, the more assured he felt.

This is because only those who have knowledge dare to explain everything in detail, while those who are half-baked are most afraid of showing their weakness.

This is indeed the case. After Evelyn introduced the various materials for making circuit boards, she began to operate steadily.

First, take out a piece of wax paper and spread it flat on the steel plate on the workbench. Use a pen to carve the pre-designed circuit diagram on the wax paper at a 1:1 ratio. Then, comparing it with the wax paper, cut out a small board from a 41-inch × 49-inch copper-clad board and trim it to the size of the circuit diagram.

After finishing, use double-sided tape to neatly stick the wax paper with the circuit diagram on the cut copper-clad board.

Then, Evelyn asked Ethan to put on a mask for chemical work, open the paint, take out the talcum powder, mix the two into a printing liquid with appropriate viscosity, and then dip a brush in it and apply it evenly on the wax paper in the same direction.

Since this step did not require any technical difficulty, Ethan operated it very quickly.

But at the same time, he also had a problem.

“Why does this thing have to be brushed in one direction?”

"Wouldn't it be more convenient to brush repeatedly?"

"It's simple. Repeated brushing can easily wrinkle and tear the wax paper."

Although Ethan's question was stupid, Evelin didn't mean to laugh at him at this moment. Instead, she explained seriously, "If it's a plastic-sealed model from a factory, you can paint it a little wildly, but you have to be careful when making it by hand, because once the lines on the copper plate overlap, the effect of the board will deteriorate or even be scrapped."

"learn."

Ethan felt that he had learned something.

After the circuit was printed, Evelyn asked Ethan to place it in a ventilated place to dry.

This process requires waiting, so the two of them took this opportunity to go to the kitchen and make some food.

Ethan made a fried egg sandwich, but unfortunately he didn't control the heat well and it was burnt on one side.

But that’s not important, right?

At this moment, their minds were all on the production of circuit boards. After filling their stomachs, they returned to the garage.

As the board dried, the next step became very important, because they needed to peel off the non-circuit parts and use etching liquid to etch away the unused copper surface. This step was performed by Evelyn. She carefully took out the potassium chlorate that Ethan bought, weighed out 1 dram with an ounce scale, and then prepared 8 teaspoons of 15% hydrochloric acid and mixed them together.

Next, apply the circuit board very carefully.

Although the chemical protective mask was not comfortable to wear, Evelyn's steady movements made Ethan feel at ease.

During this process, she also said, "Ethan, actually, there is a wild way to operate this step. Some people like to prepare a ferric chloride solution, which is 40% ferric chloride plus 60% water, and then directly rinse the circuit board. If you do that, the corrosion will be completed quickly, but I don't like it because I can't control it well and often splash the solution everywhere."

Ethan laughed at the honest words.

"It doesn't matter. The worst thing about doing things is being impatient, right? We're not competing. We're not in a hurry."

Ethan only replied with one sentence and then closed his mouth. He didn't want to distract Evelin.

Evelin didn’t say anything else, concentrating on her work.

After she had corroded away the excess copper layer, she asked Ethan to bring the clean water that had been prepared in advance to rinse the plates.

After making sure there was no residue, she bent over and worked for half a day and asked Ethan to open the banana water and wipe off the paint on the circuit.

As Ethan moved, a board with a green background and a copper core appeared.

At this point, the matter is not over yet.

Next, Evelyn punched holes in the board while Ethan, under her guidance, mixed the rosin and acetone.

"What you are mixing now is called flux. Applying it on the circuit board can remove oxides and oil stains, prevent re-oxidation, and increase the welding area. It is very helpful for welding."

Meanwhile, Evelyn had already applied flux to the board.

Then, the whole garage was filled with smoke.

Because solder wire contains a certain amount of lead, Evelyn still wears protective gear. In this case, Ethan can't see her face at all, but sitting next to her, he can feel the seriousness under the mask.

I don’t know how long it took, but when the word "OK" came out, Ethan came back to his senses.

"Are you done?" Ethan asked in surprise.

The next second, he also glanced at the clock on the wall.

The direction of midnight made him quickly say, "Thank you for your hard work."

"Oh Ethan, this is the first time I heard this from your mouth. Before, you always said thank you sister."

Evelin took off her protective gear and said with a smile, “But I like the feeling now.”

"When you said thank you before, it was just perfunctory."

After teasing Ethan, Evelyn held up the circuit board again and said, "I don't make a lot of this kind of thing, and I don't know if there's any problem with the solder joints, so why not give it a try?"

This suggestion made Ethan very happy, and he took out the TV used for yesterday's demonstration.

Evelin smiled in silence at his anxious look.

She connected the prepared circuit board to the TV and then powered it up.

After a flash, countless snowflakes appeared on the TV screen.

This scene made Evelin frown slightly, and then she knocked on the table hard.

There was a crisp "clang" sound, and the steel plate on the table made a mournful sound. The TV on the table shook suddenly. The next second, the snowflakes on the screen disappeared instantly, and were replaced by a black world.

This world is framed by white lines.

In the middle of the box, there is a pixel strip that is half the length of a finger.

After it appeared, it stayed in place for three seconds, and then bravely moved forward to the right.

It took about five seconds to complete the horizontal path of the NTSC standard TV, covering about three hundred pixels.

Then, it ran into the white border.

Then, the screen vibrated.

A huge word appeared in the center of the screen——

Game Over.

Note: ① According to the recollections of Apple founder Steve Wozniak, in the 70s, the process of making video games was similar, taking about 4 days to 1 week. What people lacked at that time was not technology, but inspiration. ② NTSC: National Standards Committee of the United States.



(End of this chapter)