Today I disassembled a CD player and gave a brief introduction to its brand: KENWOOD, model: KDC-C717.
As for this brand, I took a quick look online. It is both a British and Japanese brand. If it is kitchen appliances, it tends to be British, and if it is audio and communications, it tends to be Japanese, so I will just treat this as a Japanese brand.
Speaking of CD players, when I was young, around 2000, I had seen home CD players, portable ones, and three-disc CD players, but I had never seen one with 10 discs like this.
I just happened to pick up this thing at the garbage station. I couldn't tell what device it was at the time. I only saw a CD. There weren't many interfaces, just one interface, and there were brackets at both ends to fix the device.
Next, let's take a look at the entire disassembly. This article has about 60 photos, and tries to introduce the entire disassembly process in as much detail as possible.
The most important thing is to see how he implements the disc switching function.
Let's look at the appearance first. There is a sliding window on the front, which opens to the CD compartment. There is only one button. I don't have a power supply, so I can't test it. When I picked it up, there was also a bag of power cords, but I didn't take them. This was what I asked Xiao Hei for, so I didn't take any other accessories.
I did a quick search on the internet about the model of this CD and found out that it is for car use, the device that was used to play movies in turns on buses in those years. So I think the shockproof performance of this machine should be very good, after all, it is always shaking on the bus.
The CD compartment is quite thick and can hold 10 CDs at a time. There is a switch next to it, but its function is unclear. I don't know if it is for turning on the computer. There are no other buttons that can be operated.
There is a bracket on the left side of the device. I took it off because I had to pack it in my bag and take it back to disassemble it. The bracket can adjust the angle. There is also a picture of the screws on the left side. It is understood that the maximum screw cannot exceed 8 mm, otherwise it may damage the internal components.
There is also a bracket on the right side with an extra interface. This interface is responsible for power, video cable, audio, and function adjustment. It has 13 ports. There are Bluetooth accessories online. Just plug it in to realize the Bluetooth function.
On the back of the device, there is a label saying 12V power supply, but I don’t understand the rest. On the right side, there is a yellow label saying Class 1 laser product.
There is also a black label next to it, Made in Malaysia.
I'm not sure which one of the labels is the production period, it's definitely not Y22, this thing is antique level, at least ten or twenty years old. The one with 10705636, I don't know if it's from 2010.
The brand logo is right above.
Next, open the top cover, and you'll see a board that takes up half the space, two ribbon cables, an interface board on the right, and a CD driver board underneath.
One motor is soldered directly onto the board.
The whole is divided into three PCBs, and the rest is a mechanical structure. The mechanical structure should consist of two parts, one is responsible for pushing the CD compartment out, and the other is responsible for switching the CD.
Let’s look at the first chip first. The brand is NEC Electronics. NEC merged with Renesas Technology on April 1, 2010 to become the current Renesas Electronics of Japan. So this chip should be a product before 2010. It has the silkscreen D784214GC098. No information can be found. It should be a processor responsible for processing video signal output and motor control.
This is also from NEC, the D63711AGC, and it is the industry's first RF amplifier for CD players.
The CD player market is mature (in fact, saturated) in the home audio and portable sectors. However, this is not the case in the automotive sector, which is expected to grow at a rate of about 10% per year. The latest player systems need to provide high cost performance and save space by reducing the number of components. In the automotive field in particular, the CD player needs to be as small as possible because it must coexist with other devices such as mini disc players and car TVs in a limited space. The CD single-chip LSI D63710 was developed to meet these requirements. The D63710 integrates the functions required for a CD player on a single chip, and in addition to the existing product specifications, it also includes an RF amplifier and its peripheral components to increase system integration. As a result, this LSI can reduce the number of external components, helping to create a small and cost-effective system.
This LA 6576 brand is SANYO Semiconductor, and is a monolithic linear integrated circuit 5CH optical disc drive.
LA6576 has VREF fine-tuning function
This Sanyo LC3564RT-70 is a RAM. The LC3564RT is an 8192 word X 8-bit, asynchronous, silicon gate, low-voltage CMOS SRAM LSI. They operate at 2.0 to 3.6V, making them ideal for handheld battery-powered devices. They are fully CMOS devices that use 2-layer A1 wiring for high-speed access, low operating current consumption, and very low standby current. They combine control signal inputs; OE for high-speed memory access. And 2 chip enables CE1 and CE2 for power-down and device selection. They are ideal for systems that require high speed, low power consumption, and battery backup or easy memory expansion. The extremely low standby current means that backup can also be achieved using capacitors.
Let's look at the interface. The interface plug is a 13-pin, connected to the motherboard through the PCB cable, without other components. It is just a transition interface.
There are two flexible cables, and there are multiple SMD transistors at the interface.
Remove the interface board and the connected cable together.
At the bottom is the CD drive, the part with the laser head that reads the disc.
The whole machine's shockproof function is held in place by two springs, this is the spring on the right.
This is the spring on the left side.
With these four pad-like things, the shockproof effect of the whole machine is greatly improved. The whole device can be suspended on the casing.
Remove the mechanical structure of the back cover. It consists of three parts. The two 45-degree inclined ones control which CD the CD player reads, and the two horizontal ones are used to fix it.
There are also two 45-degree guide rails on the front to adjust the position of the CD player synchronously.
Remove the mechanical part of the housing.
The CD compartment can be removed, and the entire internal structure of the CD player can be seen.
There are ten CD compartments, each with a buckle to put it back in place.
There are two track grooves at the bottom. The long middle one is used to pop out the CD compartment, and the short one is responsible for positioning and fixing.
Push it in manually and the mechanical card will fall down and lock the CD compartment.
The cylindrical one will also get stuck in that short track slot.
There are two sensor switches, one for detecting the door in and the other for detecting the CD in which compartment.
Turn the main board over and pull the motor soldering wire off directly.
The motor is responsible for opening the door. The whole system uses 4 nylon wheels to drive the spring-loaded iron sheet at the bottom to open the door. When pushed in, the spring has an elastic force, and it should be easy to push the door out. Combined with the tension of the black spring in the middle.
There is a C02 next to it, and the four pins on the left are linked together, it seems to be a power management chip.
The long strip on the upper left is a Japanese ALPS RDC10 resistive position sensor with a 32mm stroke and a 5mm shaft length. It is responsible for detecting which CD is currently in use. It has a long sliding space.
In the gear part, the motor drives the spiral gear, which drives the other three gears to drive the mechanical structure at the bottom to push out or push in the door.
Japan ALPS Alps RDC10 resistive position sensor.
The button to open the door. The function of the switch next to it is unclear.
Now that you understand how to open and close the door, let’s learn the key point: how to switch the CD, and then continue disassembling.
Remove the cable. Only the CD player is left.
Remove the part on top of the motor, which has 4 gears. This should be the mechanical structure used to switch the CD.
The power is transmitted to this bevel gear, which then drives the blue nylon part.
By putting on the original gear, you can see the entire mechanical structure. The blue horizontal tooth part is used to adjust the up and down position.
The drive comes from the main motor power of the CD. When the motor goes up, it drives the reading of the CD, and when it falls down, it drives the gear to change the CD.
When the motor is turned up, it disengages the four gears and spins at high speed to read the CD. The gap in the middle is just enough for a disc.
Let's look at this part of the structure. The rotation of the gear can confirm which CD needs to be read according to the signal given by the potentiometer. Then the CD motor reaches the specified height according to the signal given by the mechanical position. The drive motor first retracts the inside, and then moves to the required position to extract the CD.
The spring has a lot of force and needs to be pushed. The force generated by the two springs drives the disc replacement.
This mechanical structure is similar to the structure of tape recorders in those years, but the tape recorder structure has more gears than this, but there is only one driving motor, and different gears can be switched by adjusting buttons.
There are two motors, the longer one drives the laser head to read the position.
The laser head driver board is removed. The motor is from the Japanese Mabuchi brand, model FF-050SK-13130, a disk drive motor.
The motor drives the laser head to position and read the CD.
Remove the ribbon cable.
The optical drive laser head is fixed with a whole piece of aluminum alloy.
I took off the laser head. After so many years, the lubrication is still so sticky.
The laser head is fixed by two springs and can be shaken up and down and left and right.
Remove the cover, the shaking part should be electrically adjusted with a coil.
Remove the laser head, and you'll find the core component, which can read CD files.
Internal structure.
Tray motor.
Model RF-300C-13300, same brand as the previous motor, made in Vietnam, production date uncertain.
This is the overall disassembly, revealing a bunch of mechanical structures.
There were also a bunch of small parts. Finally, they were all packed up and thrown into the trash.
This is the reading lens part of the laser head, and there is a prismatic structure inside that reflects light.
Roughly speaking, the whole machine has three motors in total, with a mechanical structure to realize the opening and closing of the door, switching CDs, reading CDs, and transmitting the video signal to the screen through the 13PIN interface. The device should have the function of automatically reading and switching to the next CD, without human intervention, and can automatically loop playback.
The overall disassembly is so simple. The production date is unclear, but I would guess it is before 2004. MP3 appeared later and this thing was gradually eliminated.
Ok, that’s it. The disassembly of a really useful device is finished. Friends are welcome to discuss it together. If you have any additions, you can discuss it together.
I will continue to update older digital junk next time. Or see if I can pick up other Digimon in the near future.
This content is originally created by EEWORLD forum user Zhang Xinyun. If you want to reprint or use it for commercial purposes, you must obtain the author's consent and indicate the source
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