I have a (cyberhome ch-dvd 300) dvd pla...

I wish I could find the website that gave all the repair hints for this DVD player, but I downloaded the info, and can no longer find the site. Here is what it says with regard to your symptoms. I hope this helps. I have done all the mods the site suggested, but continue to have difficulty with the remote, tray opening, etc. I have 2 machines and used to love them, but frustration has taken it's toll. Recovering from a condition with no TV picture
Accidentally switching to PAL and getting a rolling black & white picture happens all the time to baffle users, especially on models with a System or P/N key on the remote. To get back your color and sound just switch to the proper system in the menu or put in a movie of the correct type and it can switch automatically or try the procedure below for resetting to the defaults.
Sometimes owners will accidentally switch to Progressive Scan in the menu then get no picture at all. You can fix the no picture condition on the CH-300 by resetting the defaults to interlaced as mentioned in the users manual:

"To reset the VIDEO OUTPUT, turn Off the player, turn back On, open the disc tray and press and hold the Stop button on the player for 10 seconds to reset the scan mode."
The Reset procedure doesn't seem to work on all versions but you can sometimes get a usable B&W picture allowing you to get to the menu and change the settings by connecting the composite video input of your display to the Red Pr/Cr or Green Y component output jacks on the rear of the cabinet.
You can also go into the Menu and set it blind with the following key presses on the Remote:
1. With the unit Stopped, press Setup.
2. Press Enter.
3. Press the Down Arrow 3 times.
4. Press the Right Arrow Once.
5. Press Enter.
On 300Z & 300ZS models if the video is set to Progressive Scan and you can't get a viewable picture on the Red or Green jacks try going into the Menu blind and changing it back with the following key presses on the Remote:
1. With the unit stopped, press Setup on the remote.
2. Press the Right Arrow Once.
3. Press Enter.
4. Press the Down Arrow 2 times.
5. Press Enter.
6. Press the Up Arrow 2 Times.
7. Press Enter. This should switch it back to Interlaced scan with S-Video and Composite output.
To change the Parental Control setting on the CH-300 use the factory password of 3351. For the CH-400 use 1379.