Weird Snafu Glitch - Troubleshooting

[Ignorama]

Snafu does weird stuff on my Sears System. As you can see on the picture, there are four snakes (thats normal) and four aditional obstacles. But this is Game Mode 1, it should be without any obstacles. Its not just a graphic glitch, if you crash into them you die. The number of the dots and the placement seems kind off random, but there are some combinations more common then others

 

First I thought may my cart is broken, but I downloaded a ROM and used my LTO Flash and it does exactly the same thing. Has anyone an Idea what happens there and more important: How I can fix it?

 

Edited May 22, 2022 by Ignorama

[IntyFanMatt]

[Zendocon]

From having worked in Colored Squares Mode, I can tell you the binary difference between displaying obstacles and displaying Colored Squares.

 

I saw something similar on a Twitch livestream a few months ago, where somebody was playing Intellivision on original hardware, and one of the background cards was displaying a wrong color consistently.

 

There are two possibilities here.  Either those background cards are loused up in the STIC, or the Executive ROM in your SSVA has a faulty bit in the routine that SNAFU is using to initialize the playfield.

 

If you have an LTO Flash, try downloading the MTE-201 Test Cart ROM and running it.  You can also try the FW Diagnostic ROM for a second opinion.

[+-^CrossBow^-]

4 hours ago, Zendocon said:

If you have an LTO Flash, try downloading the MTE-201 Test Cart ROM and running it.  You can also try the FW Diagnostic ROM for a second opinion.

You will need a version that I believe is 1.4 as the previous versions do NOT know what a Sears SVA is and will give errors on two of the ROM chips as a result. You will also show a couple of letter errors that come up just after the STIC test.

 

The FW Diagnostic is able to account for the Sears version without issue.