Need some help trouble shooting an intellivision

So im new here on the forums ive had an intellivision for about 12 years now which still works great but my boss was cleaning out an attic and found his old one which he gave to me with 3 games it was working fine when i got it and now all i get is a green screen for a few seconds then a pink one and one time a glitched looking black and pink one im not to familiar with fixing intellivisions and before anyone asks i checked the ribbon cable its fine and i cant check the chips the the rf shield is soldered to the bottom half and i dont have a soldering iron atm to remove it
Any help would be greatly welcomed i was hopping to give this one to my dad as a gift

Unfortunately, I'm not a technical person for this kind of stuff. Hopefully, someone can help you out.

When you say you checked the ribbon cable, is that the ribbon cable supplying power to the main board. Did you check the volatages coming out of the ribbon cable. You can find the service manual and documentation for the voltage tests here. console5.com/wiki/Intellivision