Anyone know what this mod is?

[Bryan]

eBay Auction -- Item Number: 331881959148

 

This is a RAM module with some extra chips added. Anyone know what they're for? It looks pretty simple and my first thought was it might be a copy protection dongle for something.

[+DrVenkman]

Interesting that the chip markings on the add-on perfboard there are obscured.

[Rybags]

My guess would be a write protect switch which would allow uncracked contiguous 16K cartridge copies to be run.

 

The white wire goes to Pin 13 which corresponds to R/W.

It's hard to tell though if the extra board has a physical switch on it. If it doesn't then logically the write protect would be engaged by a write to the $D5xx area.

 

 

Removed chip markings... yeah, something that was seemingly common in the day for what's effectively a very cheap to make device, as in a few bucks which was probably then sold for 10 times or more that amount.

Edited June 21, 2016 by Rybags

[1050]

And back then they had no idea that today we can use a $40 USB programmer to detect what each

logic chip is with ground off numbers anyway. Kinda silly and cute to see such efforts.

 

Black object at top of perf board is two DIP switches I believe and I'm thinking it's a rom

emulator on the order of a home rolled Pill. Two switches may allow for 8K/16K

selection as well. The green wire underneath does connect to pin 3, R/W, of 4116.

Copy protection dongle it is. I don't recall seeing any others like it though.

[Rybags]

8/16K makes sense if you want to use programming language carts and maximize available memory.

For games, doesn't really matter. Most games run with 16K Ram, probably all the ones that need 40K or more are banked carts anyway.