LC 1 vs 2 vs 3

[David Goodson]

Apologies if this is mentioned elsewhere.

Am I correct in thinking that you can put an LC II motherboard in an LC I case (& vice versa) but you can’t do that with an LC III?

 

[jessenator]

The LC uses the edge connector for fan and/or speaker, IIRC. The LCII moved to pin headers, so you'd need to swap other LC II components to get everything connected (i.e. you can't use LC speaker and fan with an LCII board, or maybe you can since the edge connector is still there???) Other than that, the board dimensions are as near as makes no difference close enough, so the case swap should be no-problem doable.

The LCIII board moved components around, making the dimensions slightly different, so the fan placement might be different… Not sure on that one. Moving an LCIII board into an older case might prove problematic, based on photos of the boards.

Maybe relying on Cunninham's law might draw in a complete/correct answer here

 

[Nathan]

I swapped an LCIII board into a LCII case several years ago and I don't recall there being any problems with that. FWIW I want to say there's enough spare room that the board's shorter clearance to the fan isn't a physical issue (the fan is held in by clips to the left and right relative to the above pictures). Presumable the other direction (LCII board -> LCIII case) is also amenable, given that the boards are essentially the same in dimensions and components as well as the side notches. You know excepting the spacing difference near the fan which shouldn't be an issue as the LCIII case has space for the fan and the LCII boards leaves more room, not less.

you can see the extra space near the fan here:

https://ancientelectronics.wordpress.com/2017/10/12/macintosh-lc-ii/

My guess would be that you could probably migrate a Macintosh LC board forwards with some caveats relative to hooking up various components and a LCII might fit into the LC chassis. It does look like from the below page that the LC had a larger fan+surround design that might not permit fitting the LCIII board, though and the total lack of the edge connectors might be a problem.

https://ancientelectronics.wordpress.com/2017/09/28/macintosh-lc/  

P.S.  

It's also worth noting that the PSU connector moved from the LCII board to the LCIII version IMHO it's a bit of a tight stretch, but plugging the LCII's PSU worked okay.

 

[Elfen]

LOL! I have an LC case with an LC II Logic Board in it, and a LC II with a LC Logic board in it. I managed to get these systems separately and months apart, so they were not from the same seller. It just happened to happen that way. I could switch the boards around to get them into their appropriate cases but for now I have not.

But as stated, the LC Logic board need that plastic piece with the fan and speaker on it, and it is there inside the LC II Case.

 

[David Goodson]

Thanks for the feedback. Very helpful.

 

[Scott Baret]

It's very easy to swap between the II, III, and 475 boards. In fact, where I went to school, we swapped several of our IIs for IIIs just in board. (We also had to buy hard drives because we we bought the stripped-down LC II without them and the III, of course, requires 7.1).

Speaking of which...if you upgrade, be aware the LC and LC II run fine with System 6.0.6+ and 7.0/7.0.1, as well as 7.1 with no enabler...but the III and 475 both require 7.1 with an appropriate enabler. It's 003 for the LCIII (easy to remember, put 3 and III together!) and 065 for the 475 (also easy to remember, rearrange and you have 605, which is the Quadra equivalent).

The LC II actually has the contacts for the LC I speaker assembly. Look up the board. The III lacks this. I think I actually have a II board with the speaker assembly from the I in one of my LCs...

One other word of caution: the RAM is different between the I/II and III/475.