Differences in Electronics of 2600 & 2600A?

[atwwong]

I was trying out a River Raid cart from South America on my 2600A (four switcher) and my wife's newly re-discovered 2600 (six switcher) from our basement cooler. The cart works fine on the 2600A, but does not with the 2600. Combat works in both, of course!

 

I've looked all over the web, but have not found any mention of electronic differences, i.e., roms or circuitry, concerning the 2600 and 2600A. The 2600A seems more compatible with newer or odd carts than its predecessor; perhaps through a possible upgrade of either the roms or circuitry. Does anyone have any facts or interesting speculation on this subject

[atwwong]

Nevermind, the South American cart wasn't pushed in all the way in the 2600. It has a different design. Still, I wonder if there are differences in the two systems (electronically, not counting the heavy-sixers and the switch designs) ...

[Mindfield]

Frankly, there are virtually no differences in circutry between the two. All the main chips (6507, TIA, RIOT) are identical, they all use the same voltage regulator -- mostly the only differences are cosmetic, with the exception of having moved the difficulty switches to the rear.

 

Possibilities in how one works on one and not the other would include things like making sure the cart's edge connector is clean (isopropyl alcohol and a Q-Tip or a small pencil eraser work well), make sure the 2600's cart slots are clean, and making sure that they all make proper contact with the cart.

 

It's a possibility, for example, that one of the trace lines on the cartrige port has become a little worn. Coupled with a console that may not be making 100% contact with its carts, this may cause that trace line not to make proper contact with the cart port on particular unit.

[atwwong]

Thanks Mindfield, I had to really shove that cart in there... I'm babying the 2600 a lot cuz I'm afraid I'll break it, but after sitting around in the garage and cooler for XX-years, it's probably more sturdy than I give it credit for.

[Mindfield]

In fact, they're built like tanks. They can take a fair amount of punishment, and even when they die they're usually fixable with a few easily salvageable components. :-)