Defender/Stargate chip compatability

modessitt

Volunteer: Encyclopedia Submission Moderator
Joined
Mar 22, 2007
Messages
33,414
Reaction score
325
Location
Austin, Texas
I have a Defender that works fine except for an all red background. It has been narrowed down to the CPU and is NOT a monitor issue.

I want to replace the SN7489N at 2C on the Defender CPU to see if it fixes my red issue. However, I don't have one handy, nor another Defender CPU.

I do have a Stargate CPU with some corrosion issues around the battery area. Will the 74S189N at 2C on the Stargate board work on the Defender board in the same location?
 
Probably not. The power consideration between the two chips usually lead to bad results when you go from a 74xxx to a 74LSxxx. The L standing for Low Power. Going the other way doesn't seem to cause the same kind of issues from what I was told.

If you need one, let me check my chip pile, that number sounds familiar. I probably have a couple of them.

ken
 
Yes, it'll work fine... but I'd suspect the transistors before the 7489.

I checked the transistor there between 7489 and the red output pin, and it was fine, unless you mean something on one of the 2C input traces...
 
Back
Top Bottom