LC early boards ?

[bibilit]

i have collected yesterday two LC's.

One of the Logic board has "Apple confidential" stickers on all the Roms while the other has a cuda switch and a big capacitor glued on a chip instead of the surface mount one.

Was wondering if those are rare or just pre-production.

Looking online, the LC prototype board has some of those features.

Will post pictures if required.

 

[slomacuser]

Upload pictures never saw a LC prototype

 

[bibilit]

Hi Janez,

i will do, not sure those are prototypes, probably early boards.

This is the LC proto board:

http://lowendmac.com/hodges/06/0626.html

 

[MJ313]

The one with the big cap is likely an early production board; people bump into them from time to time.  It is funny seeing that huge cap on there.

https://68kmla.org/forums/index.php?/topic/26692-macintosh-lc-cap-question/?hl=cap

https://68kmla.org/forums/index.php?/topic/20134-macintosh-lc-i-oddities-ebay/

Would like to see pic of the Apple Confidential Rom board.

 

[bibilit]

Here are the pics:

 

[bibilit]

No chance here, i recapped the Logic Board and the PSU, the LC give me a bong then the chimes of death just after.

Some traces were bad on the board, will keep it for parts.

Looking at the serial number, this was the 21st built in 3rd week of 1991, so not too early...

 

[Elfen]

Ha! I too have an LC with those stickers on the EPROMs and on my Classic II (early board 4 chips ROM Set) as well.

I would call it a prototype though it is not, perhaps they were used in testing OS and BIOS configurations on these sets and needed to ships them out as fast as possible? Don't know.

 

[CC_333]

I have a Classic II with such chips, and I discovered by accident (by dishwasher) that they have little UV windows for erasing, so that would seem to support Elfen's statement.

The fact that these machines have EPROMs, when the vast majority of machines seem to instead have regular ROMs is interesting in itself. It would seem to be related to where in the production run they were built, as it seems to be mostly the early models that have these chips.

c

 

[unity]

Typically the best way to pick out a proto/pre-prodution is via the machine's serial. As for why EPROM versus ROM. Sometimes the hardware is finalized long before the ROMs. Remember, things were a bit chaotic at Apple back then. So it seems that Apple, in a rush, may have simply ordered EPROMs to stuff into early machines to get them out the door before building the actual silicone for ROM chips. Remember Apple does not do chip-fab in house back then. As for the label, that could be an oversight, etc. Regardless, I still think its a cool variant. And the actual answer as to why they have them might not even be known. The weird thing is how late the board is versus debut of the machine to have these. Are you certain its an LC board and not some later model stuffed in an LC case?

 

[bibilit]

Are you certain its an LC board and not some later model stuffed in an LC case

Well, i can have a look, but the board has the early fan/speaker arrangement with those spring contacts instead of the late connectors ones. 

 

[olePigeon]

The RAM is also in different locations.  It's certainly different.  Is there a possibility it was paired with a TechStep or some other diagnostic hardware/software?  You could change the ROMs out or something.

 

[yuhong]

This also reminds me of the difference between 350mil vs 300mil 4Mbit chips.