Jump to content

Recommended Posts

Hello, I recently bought a 128k Mac (non-functioning) and the seller told me that he thought that the 74F253 Ram Multiplexers were bad. But after replacing them with new Motorola ones, the screen still has the same issue. Here is a photo:IMG_1379.thumb.jpg.365241eda5b122a9c4308a9410be89cc.jpg

I have no idea where to got from this point and a google search came up inconclusive. Please Help!!

Share this post


Link to post
Share on other sites

Did you swap just the ROMS or the entire board. I would have swapped the board, a lot easier and would rule out bad RAM.

Share this post


Link to post
Share on other sites

You yourself socketed and replace the RAM?

Does not matter about board fit, its compatible for testing. You dont have to put the rear bucket on.

Edited by unity

Share this post


Link to post
Share on other sites

If the ROM is good, and the RAM is good, then one of the GALs/PALs could be at fault. 

 

OR there is the rare possibility that this mac had a memory upgrade and someone removed it trying to get it original but didnt undo the mods required to the board. 

Edited by techknight

Share this post


Link to post
Share on other sites
19 hours ago, beachycove said:

I guess there are the best looking and the friendliest. You might want to take one out!

Wish I could upvote this post :) 

 

But yeah lets get a good picture of the motherboard, I'd say.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×