Pre-Production LC

[agg24]

I was beginning the recapping process on a recently received LC when I noticed printed labels on the LC's ROM chips. In addition, when I initially received the machine, I was struck by some sort of red reset button inside the case, but assumed I wasn't familiar with the LC internals. I did some searching, but found very few mentions of this on the internet, with one user here at 68kMLA mentioning owning one and a Lowendmac article on on older prototype, named "Elsie".

The top ROM (LL) is labeled:

341-0392-LL

1.0GM 10/11/90

Apple

Confidential

(c) Apple 1983-90

The other ROMs simply have the ROM number and (c) Apple 1983-90 in a printed on label.

I assume given the "1.0GM" on the top ROM means this was a very late pre-production machine, likely right before release. Once I finish recapping it I'll turn it on and see if there is anything else unusual about it.

 

[bibilit]

I have got one or two of those myself, including stickers on all Roms.

Apparently pretty common, probably early models where released with the cuda switch, stickers and this big cap.

Later models had lost those features, apart from that, they are just standard units.

 

[agg24]

Interesting. Any idea why so many exist? Seems weird for them to label so many machines with a supposedly GM version of the ROM, along with the cuda switch.

 

[agg24]

A few more mentions of this hardware: https://www.fenestrated.net/mac/MacLC/index.html and the related discussion here, along with screenshots of a board like mine https://ancientelectronics.wordpress.com/2017/09/28/macintosh-lc/.

 

[Franklinstein]

I have one too. It came with a DayStar Value 040 installed.

 

[switch998]

Interesting. Any idea why so many exist? Seems weird for them to label so many machines with a supposedly GM version of the ROM, along with the cuda switch.

The boards are probably from a PVT run, which is essentially the last stage of prototyping where the design is finished and Apple begins testing how the production scales. Depending on how the run goes, they could either scrap the boards or throw them into production units if no revisions need to be made.

It's unusual to find these boards in normal machines but it does happen. I remember when I purchased my White C2D Macbook on launch day directly from Apple, it with "PVT" silkscreened on the board. Most of the time, if the machine is truly a prototype, you'll find EVT/DVT/PVT in the system's SN, but there's no hard and fast rule about that.