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I think I might have just bought an LC prototype


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The machine's missing a model label and the rom chips look like there's APPLE CONFIDENTIAL REX (V8) written on them. The logic board is in a very bad condition but repair may be possible. Do you guys think this could be a prototype LC?

 

Thanks!

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That’s certainly a nice find!  That is indeed a prototype. I have two. 
 

It’s a shame the condition the logic board is in. You need to remove the battery ASAP. 

 

IF you do anything with the board I highly recommend removing the ROM chips to avoid the labels being damaged.  What is the serial number on your logic board?  SG4000 something ?

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Posted (edited)
7 hours ago, MrFahrenheit said:

That’s certainly a nice find!  That is indeed a prototype. I have two. 
 

It’s a shame the condition the logic board is in. You need to remove the battery ASAP. 

 

IF you do anything with the board I highly recommend removing the ROM chips to avoid the labels being damaged.  What is the serial number on your logic board?  SG4000 something ?

I'm still waiting for it to arrive. I didn't ask the seller any questions since they obviously didn't know the LC they were selling was special. The board will definitely need a recap and I'm worried there might be some damaged traces and pads. The Y1 clock crystal is missing completely and there's capacitor and battery gunk all over the board. I'll have to get a donor board most likely. I've actually found a very similar board on Ebay but the seller is from the US so shipping to EU would be a problem.


I don't know the serial number but on the low quality photo I can see SG038 something, I believe.


Edit: black and white SN photo

F0FEEF09-A01B-4D67-B3B4-647C5955910D.jpeg

Edited by kupouzar
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Nice find, although it's odd how many LC prototypes seem to be floating around. I think that board could be saved, but will need extensive work - the legs of the processor don't look too good. Will require a lot of removal of ICs and resoldering.

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10 hours ago, joshc said:

Nice find, although it's odd how many LC prototypes seem to be floating around. I think that board could be saved, but will need extensive work - the legs of the processor don't look too good. Will require a lot of removal of ICs and resoldering.


I agree it’s really strange how many of these there are. I’ve randomly encountered two, plus a IIsi prototype. All from eBay. 
 

I think what happened was support professionals within Apple were sent late stage prototypes for training and then once they were released nobody cared about them and they were taken home by employees. 
 

Two that I purchased came from Minnesota, and from what I’ve gathered there were a lot of Apple employees living in Minnesota. A seller on eBay that recently sold a IIcx prototype had sold me a IIcx prototype last year. He told me he got it from an Apple engineer and that there were a lot of them around that area. 

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On 5/17/2021 at 6:26 PM, MrFahrenheit said:


I agree it’s really strange how many of these there are. I’ve randomly encountered two, plus a IIsi prototype. All from eBay. 
 

I think what happened was support professionals within Apple were sent late stage prototypes for training and then once they were released nobody cared about them and they were taken home by employees. 
 

Two that I purchased came from Minnesota, and from what I’ve gathered there were a lot of Apple employees living in Minnesota. A seller on eBay that recently sold a IIcx prototype had sold me a IIcx prototype last year. He told me he got it from an Apple engineer and that there were a lot of them around that area. 

So I've just received the unit and started cleaning the board. However, there're some missing components and lots of bad capacitors, I'd be glad if you helped me identifying them - maybe one of your boards is similar to mine. I really hope those brown rusty spots aren't damaged traces…

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Wow!  That is some significant damage to the board. 
 

The two LC prototypes I have show serial numbers SG4000 [something].  If they are decoded in the same way the machine numbers are decoded, this is what it means:

 

Manufactured in: SG => Singapore
Year of production: 1990
Week of production: 38
Production number: 089 => 281
Model ID: 03G- => unknown Mac

Your unknown Mac was the 281th Mac manufactured during the 38th week of 1990 in Singapore.

 

I personally don’t have the expertise myself to repair a board that’s damaged that much. I can upload high resolution photos of my two boards and message them to you. I have recapped my boards using tantalum caps (gasp!). You should check that power supply as the board has a massive 2500uf capacitor on it and I’ve successfully replaced with a “standard” 47uf 16v capacitor on the SMD pads there. 
 

Those ROMs are really interesting and you might want to either use a reader and extract them yourself or send them to someone who has a reader. Both of my LC prototypes had Apple Confidential but were GM ROMs (meaning they’re the same as initial batch shipping). 
 

All in all, the rarest things you have there at the moment are the case, the power supply case (I’ve found the prototype power supplies use a different run than production), the contents of the hard drive, and the ROMs. 
 

It may seem too involved to repair that board and it may make more sense to you to source another pre-production board (easy to identify with the large 2500uf cap hanging over a chip), and swap the ROMs. These boards seem very easy to break from corrosion, more so than most others. The condition yours is in makes that a daunting challenge. I see chips with legs eaten. But that part will be up to you. 
 

If you ever decide to sell the case and ROMs let me know. 
 

It would be interesting if the hard drive works. If you try it on another Mac, be sure to have something prepared so you can back it up immediately. I’ve had these old drives die while using them for the first time after receiving them in the mail. They are old and unreliable. If there was some internal Apple software or tools on there it could give us a hint/peek as to the purpose of all of these LC prototypes in the wild. 
 

A year ago I picked one up and thought I had won the lottery (considering an LC prototype has been on eBay for $10k). I since got another without realizing (it was a surprise, I didn’t notice the lack of badging/labeling) and now you have one, these seem to be quite common but still fairly rare. I don’t really know how a value could be estimated because nobody knows exactly how many exist in the wild. Especially working ones, of which sadly yours is not. 
 

Please let me know if you plan to go the full restoration method and I can take detailed photos of seconds of the boards I have. 

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55 minutes ago, MrFahrenheit said:

Wow!  That is some significant damage to the board. 
 

The two LC prototypes I have show serial numbers SG4000 [something].  If they are decoded in the same way the machine numbers are decoded, this is what it means:

 

Manufactured in: SG => Singapore
Year of production: 1990
Week of production: 38
Production number: 089 => 281
Model ID: 03G- => unknown Mac

Your unknown Mac was the 281th Mac manufactured during the 38th week of 1990 in Singapore.

 

I personally don’t have the expertise myself to repair a board that’s damaged that much. I can upload high resolution photos of my two boards and message them to you. I have recapped my boards using tantalum caps (gasp!). You should check that power supply as the board has a massive 2500uf capacitor on it and I’ve successfully replaced with a “standard” 47uf 16v capacitor on the SMD pads there. 
 

Those ROMs are really interesting and you might want to either use a reader and extract them yourself or send them to someone who has a reader. Both of my LC prototypes had Apple Confidential but were GM ROMs (meaning they’re the same as initial batch shipping). 
 

All in all, the rarest things you have there at the moment are the case, the power supply case (I’ve found the prototype power supplies use a different run than production), the contents of the hard drive, and the ROMs. 
 

It may seem too involved to repair that board and it may make more sense to you to source another pre-production board (easy to identify with the large 2500uf cap hanging over a chip), and swap the ROMs. These boards seem very easy to break from corrosion, more so than most others. The condition yours is in makes that a daunting challenge. I see chips with legs eaten. But that part will be up to you. 
 

If you ever decide to sell the case and ROMs let me know. 
 

It would be interesting if the hard drive works. If you try it on another Mac, be sure to have something prepared so you can back it up immediately. I’ve had these old drives die while using them for the first time after receiving them in the mail. They are old and unreliable. If there was some internal Apple software or tools on there it could give us a hint/peek as to the purpose of all of these LC prototypes in the wild. 
 

A year ago I picked one up and thought I had won the lottery (considering an LC prototype has been on eBay for $10k). I since got another without realizing (it was a surprise, I didn’t notice the lack of badging/labeling) and now you have one, these seem to be quite common but still fairly rare. I don’t really know how a value could be estimated because nobody knows exactly how many exist in the wild. Especially working ones, of which sadly yours is not. 
 

Please let me know if you plan to go the full restoration method and I can take detailed photos of seconds of the boards I have. 

Wow, what a long message, thanks for all the information!

I'd definitely love to repair this thing as I still think it is actually possible. Haven't found any damaged traces so far.

I put the HDD into my precious Classic II and to my surprise it still works like a charm but I haven't found anything interesting on it yet.

I'm not planning to sell it but I'll notify you when I decide to.

I'd like to try the full restoration method so the high quality photos would be a great help! If the repair won't be successful, I'll try to get some board off ebay - there're few for sale right now.


Here's an Imgur link with some more photos after more cleaning:

https://imgur.com/a/KODIk3B

 


 

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The Logic Baord is in pretty rough shape, will need a good clean first.

 

Can be wrong but is one of the CPU's leg broken ? also the Egret chip is pretty contaminated...

 

Hope you can have it repaired.

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5 hours ago, bibilit said:

The Logic Baord is in pretty rough shape, will need a good clean first.

 

Can be wrong but is one of the CPU's leg broken ? also the Egret chip is pretty contaminated...

 

Hope you can have it repaired.

Yeah, there are 3 broken legs on the CPU unfortunately. But there still are smaller pieces of the legs sticking out of the chip so it should be possible to solder them back. Also one of the legs is an NC pin. I've cleaned the egret chip even more and it looks right so there still is a good chance it will work again :-).

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