Re: N3101 RAM for Missile Command

I'll put in the LS189, and let you know wether it works or not. The pinout is identical to the N3101 RAM in the schematics, I bet it is the same RAM... Can't harm to try it out.

Thanks,

Mendel

  ----- Original Message -----
  From: Rodger Boots
  To: rasterlist@vectorlist.org
  Sent: Saturday, January 31, 2004 8:46 PM
  Subject: Re: RASTER: N3101 RAM for Missile Command

  It doesn't drive the output resistors, it goes to a latch---the latch drives the resistors. Like I said, no reason it has to be open collector.

  And this game doesn't have a lot of colors, one bit for red, one bit for green, and one bit for blue. The spare bit does nothing.

  John Robertson wrote:

    Open collector is needed when you are driving colour video output resistors. You have to have an output gate that floats when it is not pulling down the output resistor. You should be able to get the same result if you use an isolation diode on each output gate, otherwise all the colours will be the same intensity and you won't get that lovely 16/32/? colours potential of these old timers...just a nine colour palette.

    John :-#)#

    At 01:28 AM 31/01/2004, Rodger Boots wrote:

      The N3101 is a Signetics number (datasheet here) that directly crosses to a 74S289 (datasheet here), and for completeness I'm including the Intel 3101 datasheet here.

      So far we have chips that are all open collector output and are obsolete. That being said, I see no reason why you need open collector outputs, it's probably just what was available when they designed the game. A 74S189 (Jameco has them here) should work fine.

      The 3101 is NOT compatible with the 5101 or 2102 or anything else. It is a very fast, very small RAM. 64 bits arranged as 16 x 4.

      MyPearl wrote:

Hello group,

I found that the COLOR RAM (at L7) of my missile command has litterary
cracked open. Weird thing is it, still works, but becomes unstable now
and
then and triggers the Watchdog.

The partnumber on the chip is 'N3101'

I cannot find a datasheet for this part, nor a source, or a cross to a
replacement on the web...

Does anyone know where I could get this RAM, or equivalent?

Hope someone knows...

Thanks

Mendel Pearl
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Received on Sat Jan 31 15:40:29 2004