Discussion on:

More IC (Cracking Open the famous Simon)

According to the Simon Story http://www.dieterkoenig.at/ccc/english/se_story_simon.htm
Simon was originally based on a TMS1000. This was a 28-pin IC and since there isn't such a chip in the photos, my guess is that Milton Bradley eventually had a custom chip made to perform the same function. Hence the "MB" in the number.

Whilst it does stand to reason that the MB means Milton-Bradley, there are more than a few PLL ICs manufactured by Fujitsu that have MB as the prefix. The most notable of which is the MB8719. The MB8719 would have been a contemporary of the MB4850 if, indeed it was introduced in 1978. Or, more likely, this idea is utter crap.

--Rob

--more-- added 10 PM EST.

The MB4850 was "replaced" with the MM9009N at some later date and the MM9009N is still available, though for the life of me I cannot find a datasheet.

Best guess is that the 8108 (or whatever) chip controlled the logic of the game, and passes the MB 4850 some n-code, which then (using frequency division, or "stepping") uses a comparator and then controls which light illuminates. Whackily like how a channel selector on a CB radio works, only with the n-code derived at via the 8108. Just a crazy stab at it.

From the position of the chip itself and the speaker wires, is it possible that it is an audio driver of some type?

Still haven't needed to replace a bulb!

I have been looking for a brand new Simon, but can not find them at the local Target or WalMart.
Where can you find them?

The reason why you can't find data on the MB4850 is it is a custom chip for Milton Bradley thus the MBxxxx part number, you didn't think MB was going to give away the secret sauce? Also why didn't you create a schematic for what you could figure out? Us reversors could do the rest!!

Looking at the chip a pretty obvious number is 8108 - surely that was a processor number. My guess is that its a microcontroller chip with rom and cpu, for Simple Simon 4k would probably be enough. The dot H might just be Hitachi or maybe hardwired or hard-coded. MB probably is Milton Bradley - the customer. The central number looks like the actual chip number SCUS -US is the USA branch but offhand I can't remember what SC stands for - I think it was one of the big chip makers.

OR - why I am not a Premium Member paying for this -


LOL -

I added a speaker out jack to mine. It was amazing how much bass was being
produced by Simon.

Drew, that switch is called a platen and is not usually used in a piece of electronics of that nature. You find them more in heavy usage industrial settings because they do not wear out easily. Although that one does look rather flimsy.