A Question about 128k ROM Compatibility

[davidmays]

Hello, I am trying to restore a 128k Macintosh. The issue is that its logic board came with Macintosh Plus roms, and all I get is black vertical lines from the video. I understand 512k roms will work in the 128k, so I was wondering if Macintosh Plus roms will as well.

If they are supposed work without modification, it will indicate an issue I will have to resolve before I look into making replacement 128k roms.

 

[SuperToaster]

Plus ROMs will not work in the 128k. However, you can upgrade it with a Plus motherboard. However, there is an upgrade called Mac Rescue which you can use the Plus ROM with.

 

[uniserver]

I put plus rom's in an original 128 before.   A 128ke is a little funny though.  Ads native support for BMOW's new HD20 emu!!!

 

[davidmays]

I put plus rom's in an original 128 before.

So were you successful? Can you drop a mac plus rom directly into a 128k logic board and it work? I'm getting conflicting answers.

Again I'm not trying to upgrade, I'm trying to restore my 128k to its original functionality. I'm trying to see if my logic board works with the limited resources I have (Set of mac plus roms, 128k logic board and chassis, functional and seperate macintosh plus)

 

[uniserver]

Can you drop a mac plus rom directly into a 128k logic board and it work?

yes.

 

[davidmays]

I see, thanks for the information. It seems I likely have a RAM issue that will need to be resolved first.

 

[uniserver]

Yup pretty typical for those 128k's

The Apple Logo'd Micron Ram is the worst.

I do offer ram replacments for those.  I also have New Ram for those as well. (Quality Samsung)

All 16 Chips should be replaced, then its done and over with. 

 

[Elfen]

The Mac Plus ROMS are the same ROMs used in the 512Ke. The ROMs on the 128K are the same used on the 512K. Since both ROM sets work on the 512K motherboard, they will work on a 128K motherboard. You just have to line the pins up right on the sockets and the high/low ROMs in their respective sockets when you put them in.

As for that bright line on the video - that is an analog board problem. There are many threads on the forum about analog board fixes or start one here. Have a picture of it?

 

[uniserver]

Elfen, I think you are mixing this thread and another one in your thought process there.

Vertical Line's is probably ram,  not to say there isn't also some issue with the A/B.

A bright horizontal line in the middle is usually the A/B yes with the 128k, 512k, Plus.  

With the SE/30, a bright horizontal line, or no video is usually an issue with cap goo rotted UE8 on the MB.

 

[Elfen]

Oh, you're right. I misread "Black" vertical line as "Bright" vertical line, the first being a RAM issue as you stated and the second being a Analog Board issue.

Sorry about that.