Problem with 5200 video

[tep392]

Hi,

 

I just received this 5200 motherboard with bad video output, so i'm trying to figure out what is wrong and get it working again. The digital section seems to be working ok as the game starts up and runs fine. But the video is showing some white "blob" that comes and goes and will sometimes cause the screen to get completely scrambled. The display will also shift to the left and partially off the screen. The linked video shows it some of the symptoms.

 

Any idea's what could be going on? Could this be an issue with the RF modulator? Or maybe an adjustment?

 

https://www.youtube.com/watch?v=fn72kGqQxVI

[+DamonicFury]

Very odd! Have you tried it with a different TV? Perhaps a CRT if you have one?

[tep392]

The previous owner had the same problem, so I'm guessing it is not the display. I'll try it on a CRT anyway to see how it behaves.

[+Mitch]

Do you have a 5200 diag cart?

 

Mitch

[tep392]

No, but if the ROM is available, I could make one. Is there a test you have in mind?

[MIKE5200]

No, but if the ROM is available, I could make one. Is there a test you have in mind?

Should be in the ROM area..Try it

[+Mitch]

No, but if the ROM is available, I could make one. Is there a test you have in mind?

 

It's been awhile since I messed with it but I think there is a RAM test, that is a possible culprit. Though it could be several different things. I would grab the 5200 service manual and go through the flow chart.

 

Mitch