I think my 128K was upgraded :(

[Mike Richardson]

I think the Mac 128K that I got the other day was upgraded

The floppy drive, as far as I can tell, is an 800K model.

Additionally, the ROM chips have an "83 - 86" (1986) copyright on them.

Therefore, I think that I do not have a real 128K but some bastard upgraded model to 512ke

The floppy drive seems to have problems, for example it won't eject disks. I have not gotten it to boot yet so I can't look in the about window or anything to verify my theories. It would really suck though if this is an upgraded 128K and not a real one.

 

[Unknown_K]

I would think most 128K are upgraded because 128K RAM is about useless.

 

[Mike Richardson]

I would think most 128K are upgraded because 128K RAM is about useless.

Practically it makes sense, but for collectors purposes it really sucks. It makes the TRUE 128Ks even more rare.

 

[Quadraman]

It happens. I have an older model that was upgraded to a Plus, unfortunately the person who did the upgrading didn't leave behind any clues as to what model it was before as they changed the back half of the case when they did it.

 

[phreakout]

Maybe the previous owner (or the owner previous to that) had swapped logic boards. This was about the most cost effective way to upgrade the computer, short of trading it in for a 512K/512Ke. You would have to be an elite hardware technician to know how to mod a 128K to handle 800K drives, more RAM and any other additional features like SCSI.

73s 8)

 

[equill]

It happens. I have an older model that was upgraded to a Plus, unfortunately the person who did the upgrading didn't leave behind any clues as to what model it was before as they changed the back half of the case when they did it.

A new case bucket was part of (at least some) Apple upgrades.

de

 

[Mike Richardson]

Luckily the case is all original 128K. I can't tell if the motherboard is a 128K or a 512Ke. It does not have SCSI so it is not a Plus.

It has an 800K drive and the ROMs say "83 - 86" so I am assuming it is a 512Ke motherboard. The board just says "Macintosh" and it has "apple computer" written with that old font.

 

[Unknown_K]

Can you just replace the ROM and a socketed chip to use 800K drives on a 128k?

 

[Mike Richardson]

Can you just replace the ROM and a socketed chip to use 800K drives on a 128k?

I'm not sure. The board looks awfully like it might be the original 128K board. The ROMs are on sockets so that's certainly possible. I'm still trying to get it to boot but all of my 800K disks are failing so I can't make a boot disk.

 

[Quadraman]

Can you just replace the ROM and a socketed chip to use 800K drives on a 128k?

I'm not sure. The board looks awfully like it might be the original 128K board. The ROMs are on sockets so that's certainly possible. I'm still trying to get it to boot but all of my 800K disks are failing so I can't make a boot disk.

Were the RAM chips soldered on the original 512? I know they were on the 128.

 

[macdownunder]

Were the RAM chips soldered on the original 512? I know they were on the 128.

Yes they were.

I haven't had my 128 or 512s powered up for a while but I seem to recall that the 64K ROMs provides a slightly different boot screen (ie more traditional MacOS 6.x double line boarders vs shadowed box on the 32K ROMS).

I also have a vague memory of the About Mac window displaying the amount of RAM available on early MacOS versions (Bottom right corner? My memory is quite vague here).

I have a number of 128 boards that have been upgraded to 512 by hand. The easiest way to tell (on mine) is to look at the solder pads (ie not uniform as expected from an automated assembly line).

Remembering the cost of the 512 upgrade board back then, it was cost effective to get a technician to do a RAM chip upgrade on an existing board (at least in Australia back in the 80's).

Regards,

Macdownunder

 

[iamdigitalman]

my Macintosh Plus is an upgraded 128k/512k. The way I can tell is because it does not say macintosh plus on the front, and the apple logo is the rased version, sitting in the lower left hand corner, not in line with the floppy drive. plus the serial number ran through a generator does not give a 1986-1990 build date.

-digital

 

[Charlieman]

You would have to be an elite hardware technician to know how to mod a 128K to handle 800K drives, more RAM and any other additional features like SCSI.

I could do that easily and I am lousy at "real world" electronics. The procedures are well recorded (thanks, Tom Lee and Larry Pina) for the simple stuff. For the more complicated SCSI stuff, do a search for "John Bass" & Mac & SCSI.

One of my non-elite technicians (but personable, communicative and an organisational asset) is on leave today (partially) to fix his VCR. Upgrading a 128 or 512K Mac is a much easier project.