Two 5200s - Two Problems (Audio, Video)

[ChrisB]

I recently brought an old 5200 out of storage, and purchased one on Ebay as well. One of the units has video issues: fuzzy display with weird static-like shapes on the screen. The other unit has a crystal-clear picture, but only static for sound. I've opened them both and switched RF cables to see if that was the cause, but they both have the same problems with the cables switched. I've cleaned the cartridge slot of the video-problem unit several times using a CC and alcohol, and have done the same on all the games, but the video issue persists.  

 

Anyone know what might be causing it, and if there's a way I can Frankenstein the two units into one unit with working video and sound? I will attach a photo of the screen issue. 

 

(Ignore the large diagonal band in the photo, which only appears due to my camera. The problem is evident in the circled areas.)

 

Thanks in advance. 

[+-^CrossBow^-]

Well the fuzzy like picture looks pretty normal for RF to me even on a CRT in most cases. Unless it looks much worse in actuality vs what the picture shows?

 

The one with the static sound is likely the polystyrene caps and or adjustment of the audio coil to tune in the audio. 

[ChrisB]

The picture is not normal. It's hard to capture it in a photo. It's got fuzzy lines and grid looking things that sort of float. The other one doesn't have that (the one with no sound). I'll see if I can figure out the audio fixes you suggested. Thank you. 

[+-^CrossBow^-]

From your last description that is likely some noise interference affecting the image output. There is a similar adjustment that can be made to the RF modulator, from the side of the box. Similar to the audio is has an adjustment coil to tune in the picture to dial it in more. Aside from that it could just be an issue within the RF modulator itself.

 

 

[0078265317]

Ot maybe take a quick video.  Video might show better than a photo.

[ChrisB]

Can you explain which is the RF modulator? I can try to do that with the unit open and connected. Also, is there one for video as well? Can I assume that this video issue is not caused by dirt on the cartridge slot? I've done everything but using sandpaper. Thank you. 

[+DrVenkman]

13 minutes ago, ChrisB said:

Can you explain which is the RF modulator?

Here's a pic of my two-port. The 4-port is very similar. The RF modulator is the metal-shielded box on the right edge of the PCB toward the rear.

 

 

[+-^CrossBow^-]

Using @DrVenkman's picture above. There are two holes one on either side of that metal box. Those are the access holes to adjust the video. If you look where those holes are and go straight left across the mainboard, you will see a red plastic coil that stands up. That is the one for adjusting the audio itself. Both of these adjustments use a ferrite core that is turned using a small plastic hex wrench tool. You can use metal ones, but as these cores are 40 years old they tend to crack and break easily using metal tools so it is advised NOT to do so. Also, using a metal tool will alter the tuning adjustment. Meaning once you have it set and it is good, then you remove the hex wrench and it goes south on you because the tool was affecting the adjustment in the process.

 

Adjusting these can be done without removing the large RF shield that covers most of the board. There is an opening on the top right side of the shield for the audio tuning to be accessed and the RF modulator box further right can be accessed from the sides as stated before.