D100 RF Noise
The D100 has an issue, it's quite diffcult to read discs.It always needs a while to read TOC and begins to count on the screen. Even if it reads the disc, we can only hear severe noise from earphone (via both line out and eraphone out) with a little music mixed in. Since it can read TOC and play discs, I guess it might have something wrong with its DSP/DAC/Digital filter part. When I increased the laser power, the noise decreased a little bit and the music became cleaner. Therefore, I'm sure the electrical circuit is working well. The issue comes from its laser part.I checked its RF pattern and found it's level was 0.6Vp-p on CDR. So I adjusted the RF to 0.8Vp-p, also the TB and FB. It still works like it used to be. I tuned the VCO, nothing happened. I found something wrong. Ordinary, if we have a clean RF wave and we count the grid on the oscilloscope's screen, we can have the level of the RF wave like 1.0Vp-p. But the oscilloscope will give a value with a little bigger number like 1.1Vp-p. It means the RF wave has some "burr". Although it's not the real RF signal, the oscilloscope counts it along with the real RF signal. The cleaner the RF sinal is, the smaller the difference will be.
In this situation, we can count the grids to know the available RF level is 0.8Vp-p; however, the oscilloscope says it's 1.77Vp-p! Why the D10 has so huge "burr"? I checked the screw connecting the PCB ground and metal frame, it's good.So, I might replace its laser for last try. When I flipped over the laser assembly, I found the cable conncting the laser upper metal cover with the PCB ground is already broken! When I soldered it with the ground, the player come back to life!
Top up! Really is a master, this problem has been found by you!!! 顾老师，我有个D100不能开机，CPU的尾数编号为003，56和26脚供电电压正常，第30脚P-CON脚为高电平，29脚reset为低电平，当我按下播放键CPU的第9脚会从高电平变为0，但是CPU无反应，屏无显示。如果我把第30脚直接接地，Q407会导通，主轴电机会动作，正负4.5的电压也正常。请问是哪里出了问题呢？？第29脚的电平是不是有问题，我该检查哪里？？？ static/image/common/user_online.gif 爱人332681713 static/image/common/clock.gif 2016-12-28 07:30
顾老师，我有个D100不能开机，CPU的尾数编号为003，56和26脚供电电压正常，第30脚P-CON脚为高电平，29脚res ...
D100 CPU CXP5806-003:
Pin 26, 58: VDD, +5V
Pin62: /RST
Pin60,61: Crystal 3.58MHz
Pin30: /P-con 多谢顾老师解答，原来62脚才是RST，我查了下电压，为5.8V，不正常，应该是5.0V才对的，立刻把D814拆除，电压为5.0V，这时按开机键屏就可以显示了，而且整个机器电源，动作全正常，按手册调整VOC，TB，FB，读碟很好，再次感谢！但是我想知道不要D814应该不会有什么问题吧？
static/image/common/user_online.gif 爱人332681713 static/image/common/clock.gif 2017-01-03 08:24
多谢顾老师解答，原来62脚才是RST，我查了下电压，为5.8V，不正常，应该是5.0V才对的，立刻把D814拆除，电 ...
You'll have to keep the D814. For the losing segments of the LCD, pls re-solder the whole CPU. It might help. :lol,thank you ,kaosun Hi master Gu, I have 2 units of D100 with noise issue. The first unit can hear minor noise with music. Second unit output totally noise.
I'll check the grounding wire as you mentioned above.
which part shall I check for second unit issue?
Thanks
For the 1st D100, it's better you replace the whole laser unit. Aging laser usually generates noise but still reads discs well.
For the 2nd D100, if it reads discs well, I believe something wrong with the digital audio part. Pls check digital filter, DAC, negative 5V DC-DC circuit. static/image/common/user_online.gif kaosun static/image/common/clock.gif 2018-03-14 15:39
For the 1st D100, it's better you replace the whole laser unit. Aging laser usually generates noise...
For the first D100 with minor noise, I checked ground connection even replaced laser unit, the noise was unable to eliminate. But when I opened the top PCB and play disk, there was no noise. Once I fixed back top PCB the noise came back.
Any suggestion, please.
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