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Mac 128k ~ Plus Analog Board Analysis


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I posted about this prior to the 68kMLA server crash, but since the data was lost I felt it time to review my past work and post an update.

 

As many of you know, I have 3 sets of classic Macintosh analog board photos. The photo that I have of the 661-0462 was acquired from an associate, and until very recently I did not own the latest edition Mac Plus Platinum board. As luck would have it though, I was finally able to acquire a brand new Apple Service board for only $0.99 (plus shipping to Japan) and have made the time to compare its components with that of the other two analog board revision that I own.

 

My updated analog board table is presented in MS Excel format. Since I now have all three board editions, I was able to accurately compare the components among the three. Are there other board editions? I would assume so based on one of my boards having an "E" at the end of its model number. I take it there must have been "A" & "B" & "C" & "D" as well, but without actually seeing such boards it's difficult to say. Apple very well could have just jumped from no letter at all to "E." Nevertheless, the absolute latest edition of this early analog board was the Plus Platinum 661-0462 edition, which sports the latest HF (high frequency) capacitors and high temperature rectifiers.

 

If any of you have examined your own analog boards and would like that data added, I would be happy to do so. Also, there are some parts of the comparison table that I have marked with a question mark because the specification was indiscernible. If you know the correct value and can prove it, I would be happy to add it to the chart.

 

Hopefully this information may be of use to those of you who wish to upgrade or repair your existing analog boards. I have included Digikey part numbers where relevant to aid you in finding the best replacements. Enjoy.

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I have an older compact, I'm not sure if it's a 128 or one of the 512 models, that has a Plus upgrade kit installed. I'm not sure if that board carries a different part number than ones intended for production line assembly, but it might. Unfortunately, I have too many computers apart right now to want to open up another one to take a look.

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003, thank you for providing that link. After examining the content of that page, I'd like to bring your attention to some inaccuracies:

 

1) Scroll down to the part that reads: "There were two basic types of analog boards (630-0102)". Eric Rasmussen is basically splitting the original analog board into two types: one with and the other without the aluminum RFI shield that ran along the top edge of the board. I have no problem with dividing the boards into different categories based on this difference, but the inaccuracy involved is where the author claims the "630-0102" series was the only series for the original Macs. That is not true. There was more than one variant of the 630-0102 analog board and then Apple released the 661-0461 and 661-0462 for the Mac Plus. So in terms of "general model numbers" alone, we have 3 variants, not two. And considering that there was more than one variant of the 630-0102 board, we can safely say that there were at least 4 variations. But by and large, the design of all these original analog boards (in terms of the PCB traces anyway) is exactly the same.

 

2) Scroll down to the section "Macintosh hardware releases" and click the 112162 & 112163 links (which lead you to Apple's technical information articles). When you open the articles on Apple's site, scroll down to the "Software" section, and under that "Mac OS Supported". At the end of the OS version number list you will see the errors that Apple itself has made! The Mac 128k cannot run System 7.0.1, regardless of what this article says! Another funny thing is that Apple claims the Mac 512k will run "up to 6.0.8"! This is funny on two counts: (1) Because Apple says the 128k can run System 7 when the 512k can't (neither can), and (2) even System 6.0.8 won't run on either of these Macs! I have both a 128k and a 512k (original 64k ROMs) and I can attest to this fact! If someone can tell me how to run 6.0.8, please do! But I can tell you for a fact that the Mac 128k lacks the RAM to run System 7, more less the lack of ROM support.

 

Perhaps someone should inform Eric Rasmussen and Apple of these important details (assuming they would even care at this point in time).

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I think the 512ke can run system 6.0.7, I know I've seen that before. But your right about the other stuff I missed that.

 

A few sites report that the Mac 512K (no "e") can run System 6. My own experiments failed; I don't think that you can boot System 6 from an MFS floppy disk. As I write, it occurs to me that you may be able to boot it from an HD20.

 

The 512Ke is essentially a Plus with a fraction of the RAM and no SCSI. It will boot System 6 and there will be enough RAM to run a small app. A stock 512Ke does not have enough RAM for System 7.

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... As I write, it occurs to me that you may be able to boot it from an HD20.

 

The 512Ke is essentially a Plus with a fraction of the RAM and no SCSI. It will boot System 6 and there will be enough RAM to run a small app. A stock 512Ke does not have enough RAM for System 7.

 

I can attest that a 512Ke with 2MB of RAM (Dove MacSnap card) and System 6.0.8 on an HD20 boots and runs quite happily, and snappily.

 

de

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A few sites report that the Mac 512K (no "e") can run System 6. My own experiments failed; I don't think that you can boot System 6 from an MFS floppy disk. As I write, it occurs to me that you may be able to boot it from an HD20.

But Apple's own site being in such error! It's shocking! But the fact remains that it is in error!

 

Well, I myself can attest that a 512k with the stock 512k of RAM will not boot System 6.0.8 on an HD20 at all, more less a 128k! And remember that Apple's technical article says that the 128k can run System 7, which is just complete foolishness. Anyone know someone at Apple who can be alerted to this?

 

The best I've been able to do is Finder version 6.0 with a System 4.x or 5.x version. Any newer Finder than this won't work at all. In fact, I think I posted about this in detail on this very site prior to the crash. I'll have to Google for that later today -- it was an extensive report. But again, 6.0.8 will NOT run, even with the HD20.

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  • 3 months later...

Since JDW opened this thread up again in a recent post about cap replacements, I figured I would ad to it.

 

First, congratulations and thanks are in order for JDW's thorough documentation of the Plus analogue board in that Excel spreadsheet. Wow. Nice job!

 

And the pictures JDW took of the Analogue board, incredible. Nice detail. Some of them are worthy of Macintosh marketing "beauty" shots. Reminds me of that ad where the rear bucket is off and the analogue board is backlit in some dolly shots:

about 1:08 into it.

 

Now, in setting up the M0001 Registry database and polling which categories should be included, I have also been assembling the various part numbers of my old Macs. One thing has become clear to me. The part number 630-0102-* is not the best number on the analogue boards to use. In fact it is somewhat ambiguous. Also, JDW, I have no idea where you are getting the part numbers for 661-0461 and 661-0462, They are nowhere to be found on any of my boards or your incredibly detailed pictures. Are they catalogue only numbers ... if so they are of little use in actually identifying the boards in the field. Regardless, the best part number to use is on the solder-side of the analogue board and begins 820-0082-*, you will see as follows:

 

LEGEND: MAC DATE - 630# / 820# COPYRIGHT DATE

Macintosh: 2/84 - 630-0102/820-0082-B 1983

Macintosh: 4/84 - 630-0102/820-0082-B 1983

Mac 512K: 9/84 - 630-0102/820-0082-C 1983-84

Mac 512Ke: 11/86 - 630-0102/820-0082-D 1983-84

MacPlus 1MB: 9/86 - 630-0102/820-0082-D 1983-84

MacPlus 1MB: 11/86 - 630-0102-J/820-0082-D 1983-84

Macintosh Plus: 8/89 - 630-0102 J/820-0082-E 1986

Macintosh Plus: 6/90 - 630-0102 J/820-0082-E 1986

 

So from this you can see that most of the analogue boards do not include a letter after 630-0102 at all. In fact JDW claims 630-0102-E to be a later version of the analogue board, but clearly both of the MacPlus 1MB boards were earlier then "the very latest" and have "J" suffixes. In fact, I happen to own one of the very latest Mac Plus computers ever made in June of 1990, so unless they made a last minute revision in the last 3 months of production, this is specious reasoning at best. This again is why I feel the 630-0102-* is not a good number on which to base revisions and certainly not Apple internal catalogue part numbers, which may well have been the part number for the analogue board since day 1 (according to [urlhttp://www.vintagemacworld.com/part_nos.txt]Charlieman's site[/url] there were at least two) and JDW throwing them into the mix only confuses things further. So, whatever those 630# suffixes were meant to clarify, my guess is it had little to do with the version, at least macro versions, but possibly subtle variations within a major update.

 

As for the revision history, the 820-0082-* number provides a much more clear picture of it. As you can see a very early Macintosh 128K (2/84) was already using a Rev.B board. Since the Macintosh was in production as early as December 83 (based on what I recall), there may well have been a Rev. A board in the first couple of months of production. It appears as though the Rev. C board may have corresponded to the 512K introduction. Rev. D would seem to correspond to the introduction of the Macintosh Plus 1MB and the Rev. E likely with the introduction of the Platinum Plus 1MB in roughly 1/87, or a year later with the update that dropped the "1MB" from the name, depending on the changes.

 

This is where the M0001 database is going to prove invaluable ... it should fill in the blanks between the years I have listed above and more. Tell your friends!!

 

Finally I think the criticism JDW lays on Eric Rassmusen's incredibly detailed and painstakingly researched website is completely unwarranted. First Eric only covers the analogue board part numbers under the 128K & 512K hardware section, NOT the 512Ke/MacPlus hardware section, where he only discusses the case identification and ROM revisions. I think the sections are clearly delineated to avoid confusion, but the fact he does not duplicate the same level of interior parts detail as with the 128/512K section might lead to confusion, except he does not list the logic board or disk drive part numbers for the 512Ke/Plus section either. So, you can fault Eric for being incomplete on the 512Ke/Plus section, or not being detailed enough, but not for being incorrect about the revisions on the 128K/512K analogue boards. As near as I can tell from looking at my own models, he's right in the broad sense, as he makes no attempt to detail the part numbers and indeed looking at the 630#, there is no way to differentiate. Clearly from my documented 820#s, there was even a third revision to the 128/512K series and the 512K might have made the jump to the D rev as well (but not likely the 128K, though more info is needed to be sure). However, to the lay person, there would be few noticeable differences and most likely subtle ones even to an electrical engineer. Aside from some obvious flyback transformer improvements, I would be hard pressed to point out many other differences ... even Larry Pina does not discuss variations in the original analogue boards except to document the flyback transformers, for the purposes of determining general age of the board. Either way, I know that Eric's study was made from obtaining a wide variety of Macintosh computers in various packaging at great expense to make these detailed observations. In the case of the analogue boards, he is commenting on the results of looking at original analogue boards contained in a broad sampling of Macintosh, 128K & 512K units.

 

As for the Apple discrepancies ... the Apple tech spec database is notoriously incorrect and has been likely since the original entries were made in the mid-90s. Its been that way for the last 10 years I have have been aware of it. Eric's fantastic website points these discrepancies out in great detail, particularly when it comes to his area of expertise, the system software versions which are a bloody mess on Apple's archives. Anyone who has ever browsed the Apple tech archives knows this. Apple is hardly infallible and people have been debating and commenting on these inconsistencies and fallacies for years on the internet and in forums such as these. There is nothing new about this and given that Apple has not bothered to correct the volumes of discrepancies throughout their Knowledgebase archives during the past 15 odd years, it is unlikely they will start now, especially since most of the information is for products Apple no longer supports in any fashion whatsoever. However, I'm all for an e-mail campaign to force Steve Jobs to change it. I mean it worked for the iPhone rebates! LOL

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...the analogue board is backlit in some dolly shots...

I'd never seen that Apple ad before. Quite stunning. Thanks, Mac128, for bring that to our attention!

 

Now, in setting up the M0001 Registry database... The part number 630-0102-* is not the best number on the analogue boards to use... I have no idea where you are getting the part numbers for 661-0461 and 661-0462

I suppose it could be argued they are not best for identification "in the field" (i.e., when looking at the boards themselves). But they are Apple analog board revision numbers (which I explain with photos later in this post). Yet, let it be known that I am no master of Apple part numbers. My focus was on replacement capacitors and other important components on the boards themselves. Even so, I can tell you what part numbers I can Google up and what part numbers I read in books versus what my own eyes physically see on the 4 different analog boards in my possession, along with an Apple Service box that housed one of my 661-0462 boards. Based on what I've read in combination with what I have seen with my own eyes, the 630-series boards are early editions created for Macs from the 128k through the Plus, while the two 661-series variants were designed and manufactured during the Plus era. And the 661-0462 part number was specifically made for the latter edition "Platinum" plus.

 

It's also important to keep in mind that many boards were later upgraded with newer parts (especially the flyback transformers) at Apple Service Providers. Because of this, you often come across a very early edition 630-0102 board that looks like a newer 661-0462. And the mention of a "heavy duty upgrade" at the bottom of page 128 in Larry Pina's "Macintosh Repair & Updgrade Secrets" gives evidence that some technically inclined people may have done these upgrades themselves, having been able to purchase the required parts in kit form from various parts vendors.

 

...most of the analogue boards do not include a letter after 630-0102 at all.

The letter in question is not silkscreened to the boards. But there is a white square silked to the top of the circuit board, at the end of that 630-0102, on which is hand-printed (in black felt tip pen) a letter which appears to be a revision to the primary 630-0102 part number. You can see that hand-printed letter in this photo of my board. Keep in mind that some boards don't have a letter at all (like my early 1983 edition board that shipped inside the Mac128 in my possession).

 

At first glance, it appeared to me that the purpose of the letter is to indicate a "minor revision" of the board. For my logic led me to think that if the board was revised in a major way, so should the silkscreened part number. However, Mac128 is correct in pointing out that even the 661-0462 boards don't have "661-0462" silkscreened on the circuit board itself (at least, none that I have seen). But I still would contend that the "661-0462" number is not only an Apple Service p/n but it is also commonly associated with later edition Mac Plus analog boards, when searching on the net for such. Hence my use of it my opening post to this thread and in my Excel file (which is posted above).

 

To make this even more clear to everyone, I uploaded two new photos to my Flickr account this evening, placing them in the 661-0462 photo category. Here is a photo of the Apple Service Box I currently own. And here is a photo of the part number section of the analog board that was housed inside that same Apple Service Box. Note my comments under both photos.

 

This is where the M0001 database is going to prove invaluable...

And I quite agree. Again, I have conducted no "exhaustive research" into these board part numbers. I simply know which part numbers serve to look up particular boards, and I've seen hand-printed letters next to the part numbers on the circuit boards to indicate revisions of some sort. So whatever further light the M0001 Database can shed on the part number issue would certainly be a great benefit to the classic Mac community.

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Based on what I've read in combination with what I have seen with my own eyes, the 630-series boards are early editions created for Macs from the 128k through the Plus, while the two 661-series variants were designed and manufactured during the Plus era. And the 661-0462 part number was specifically made for the latter edition "Platinum" plus.

 

No one is arguing that the board you received was identified by Apple as 661-0462, nor that that part number refers to the latest version of the M0001 analogue board. I would also say that it is highly unlikely the "new" board you received in the original Apple Service Box was replaced by anyone with an older model. The fact that I have a virtually identical analogue board in my June 1990 Macintosh Plus is proof of that.

 

Here's what I've learned about part numbers from the Apple Service Source (HyperCard version as the PDFs leave out a lot of detailed information only available in the stacks). Apple identified the original 128K/512K/Plus analogue board as 661-76153, despite the fact it was silkscreened as 630-0102 (and for the record none of my early boards have any letter in the little white square). The International version was Apple P/N 661-76214 and according to the service source manual, continued to be labeled with that part number after the subsequent new Mac Plus part number introduction. The difference between 661-0641 and 661-0642 seems primarily to do with the difference between the beige and platinum color schemes. In fact, the manual indicated that "the previous service module P/N 661-76153 contained either a beige or platinum [power] switch. This module has been replaced by P/N's 661-0461 and 661-0462 which specify switch color." This seems to indicate that these new numbers came into being sometime after the introduction of the Mac Plus platinum, possibly because of the confusion between the color difference. Note too that these numbers are referenced as Service Module part numbers, not simply part numbers, further indicating a difference between a box containing the current version of the replacement part and not a specific variation. To say this "service module" number indicates a specific analogue revision, is misleading and confusing at best.

 

I am no expert here either, but based on what I have seen with my own eyes and read would indicate that 661-0462 is nothing more than the inventory number of the box containing the current version of the Platinum replacement analogue board and given that at some point Apple stopped making the beige variant altogether (since by the end of the Pluses run, beige was over 4 years old), that box would have contained the latest version of the analogue board, which appears to be the 1986 630-0102 J/820-0082-E. So JDW, you are indeed correct about that, but not entirely for the reasons you assert. In fact, I would suggest that merely obtaining part number 661-0462 does not guarantee it is the very latest revision of the board, particularly if it is not new in the box. Even then, it could contain an earlier revision of the board depending on when it was stored on the shelf.

 

Without further information, I think it is safe to say that there were 4 variants of analogue board Service Module Part Numbers (i.e. the boxes sitting on the shelves in the Apple Warehouse NOT the technical revisions of the actual boards):

 

1) 661-76153 covering all Revisions of the 120V analogue board used in the 128K through the early Plus change to Platinum

2) 661-76214 covering all Revisions of the 240V analogue board used in the 128K through Plus*

3) 661-0461 covering all Revisions of the 120V analogue board used in the beige M0001 Macintosh (replacing 661-76153)

4) 661-0462 covering all Revisions of the 120V analogue board used in the platinum Plus (replacing 661-76153) and eventually all M0001 models as beige was discontinued. *possibly also covered revisions of the 240V version

 

Going back to my original list I think we safely can say that 630-0102 identifies the primary design of the M0001 analogue board unchanged from 1983 to 1991 of which there were at least three major revisions corresponding to copyright date: 1983, 1983-84 and 1986.

 

In addition there are 4 distinct letter variations corresponding to the outer 820#s embedded within the board itself indicating at least 4 major revisions overall. The 820-0082-B (1983), C & D (83-84) and E (1986) numbers seems to indicate the specific revisions to the primary design number (630-0102). What the differences entail exactly is unknown, but it is clear these are indisputable physical changes to the boards themselves.

 

Since the revision numbers are only important for support and troubleshooting, there would be no reason to differentiate them in new product inventory boxes. In fact this would only serve to make the part distribution warehouse more complicated than it need be. I think this is mostly true of and an intrinsic part of any manufacturing and distribution business operation. Also, Apple uses 661#s for things like RAM, which as we all know is supplied by many vendors to Apple and not tied to a particular revision. A quick look at this list clarifies that the RAM is not differentiated by manufacturer but by type only, meaning you request the RAM and you get whatever matching specifications from whatever vendor is currently supplying them. Perhaps a better, more direct example is the 128K Logicboard. It is identified on the board as 630-0101 (with a silk-screened white box next to it) as well as 820-0086-C on the reverse. However, the Apple inventory part number for it is 661-96152. Likewise the 512K is part number 661-96236. However, the 128K later becomes the same logic board, listing both 630-0101 & 630-0118 next to each other. Now here's where we may actually get to the meat of the matter: the dual function board only has one 820# – 820-0141-A. In fact I took that number from a late model 512Ke (11/86) which I'm pretty sure is up there with the last of 'em and seriously doubt Apple had a flurry of last minute revisions introducing a 661-series of logicboards. So it would appear that the main board design and revision number to be concerned with is the 820#. The 630- number appears to be a subset of the board's function. This seems to confirm it: http://www.digibarn.com/collections/diagrams/mac-512klogicboard/index.html

 

Once this is taken into account I think it becomes clear that the 661- numbers have no bearing on identifying the revision version of a particular analogue board and in fact should not be used in trying to identify them except in a very broad sense. (FYI, the SE analogue board puts the 820# and the 630# on the same side & location as the 630#s on the M0001 boards. But there is NO 661# anywhere on it.)

 

Oh and JDW, I think the letter hand written onto your board is a "J" much the same as appears on all but one of my Plus era boards (mine are not silkscreened either). What it means is totally speculation at this point.

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I also have one of these in the Apple Service box I bought via eBay. Label on the box is just like the picture you provide, JDW.

 

The board has 630-0108 silkscreened on it, no hand written bits. Copyright shows as "1983 - 84 - 86".

 

It was sold as being new etc, but it's been a while since I got it so I honestly can't say for sure if it was it's original tape on the box although the bag was sealed. I didn't use the board for the 128K I bought it for as I had a Plus that had a dead logic board among other issues so I used it's analog board instead and saved the "new"one for a spare.

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The board has 630-0108 silkscreened on it, no hand written bits. Copyright shows as "1983 - 84 - 86".

 

630-0108!? Really? With that exact copyright date? That would imply yet another MAJOR variant of the M0001 analogue board and since it is the only one that does not use the 630-0102 part number I've ever heard of, there's no way to know where it came in sequence. It is either the last revision of the board or an intermediate step before the board with simply the 1986 copyright date. In fact that 630-0108 is downright surprising as it implies more than a revision to the analogue board, but an entirely different product. For example the 630-0101 is the 128K logicboard. 630-0102 is the M0001 analogue board.

 

What is the 820- number and copyright date on the center of the solder side next to the speaker grille? That should help place it. Pictures would help too.

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The board has 630-0108 silkscreened on it, no hand written bits. Copyright shows as "1983 - 84 - 86".

 

630-0108!? Really? With that exact copyright date? That would imply yet another MAJOR variant of the M0001 analogue board and since it is the only one that does not use the 630-0102 part number I've ever heard of, there's no way to know where it came in sequence. It is either the last revision of the board or an intermediate step before the board with simply the 1986 copyright date.

 

What is the 820- number and copyright date on the center of the solder side next to the speaker grille? That should help place it. Pictures would help too.

 

Yes, really! And the date is exactly like I wrote. The back of the board has nothing in the area you indicate. See http://www.flickr.com/photos/16539524@N00/1781846445/ for a pic of the front. This board in marked "INTERNATIONAL" on the top edge by the flyback transformer, and has instrucctions to allow 240 Volt use by removing a jumper wire described as W12.

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I found the other number you referred to Mac128....

 

On the back side, directly under the area shown in the photo link in my previous post: 802-0107-D. The dates are identical to those showing on the front.

 

I didn't see it before due to the plastic shield that covers the back side.

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Sorry, I actually thought the "0108" was a typo. I think the International labeling has something to do with it then.

 

Without an actual international analogue board to look at, all I have to go on is the inventory part number 661-0462 (previously 661-76214). That number on your box further suggests that at some point Apple used that inventory number exclusively to reference all versions of the M0001 analogue board, the specific model supplied however depended on the territory. It makes sense that the International analogue board would have had a different part number (ie -0108) as it IS a completely different product than the domestic single voltage model, and further debunks JDWs interpretation of the 661-series numbers. I had totally forgotten about it when trying to fit your copyright dates into my collection. That's fantastic, even the 820# is different, which makes sense. But a whole different configuration than all the other Apple numbers: 802-0107-D, no less, implying at least two if not three other revisions of the international analogue board. I wonder if all of the international only part numbers began 802- instead of 820. Interesting.

 

I look forward to 240V international M0001 owners cracking open their cases and offering the details.

 

YUP! I just looked in Larry Pina's "Macintosh Repair & Upgrade Secrets" (page 57) and there is a picture of an early International Analogue Board with the 630-0108- part number (with a "B" hand written in the white silk-screened box) copyright 1983-84. Sadly he does not show the reverse to look for an 820-number (one of which does not appear on the component side).

 

Thanks stevep for clearing that up!

 

This actually opens up another question about part number 661-0462. The SE has an auto switching power supply. It makes me wonder if Apple eventually dropped the separate 120/240V versions and just went with the international version. If they were already putting auto switching power supplies in the SE, it would be far cheaper to produce just one, especially if they were simply producing replacement parts. In fact it makes perfect sense. One inventory stock number would represent a board that could be configured for either computer. The only question remaining is if it were ever installed in very late Mac Pluses sold in the US, or only a replacement part in the US. Though APple seems to clarify this: http://docs.info.apple.com/article.html?artnum=4336

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  • 2 weeks later...
  • 4 weeks later...

Mac128, on my Mac Plus Platinum analog board. removing the white cover reveals the following:

 

820-0082-E

©1986

 

I've updated the description on my associated Flickr photo accordingly.

 

I also checked the original Mac 128k analog board I removed from one of my 512k machines (which was installed prior to the 512k logic board upgrade, and which shipped with the 128k in 1984). Lifting the gray paper cover (which pre-dates the white vinyl) reveals the following:

 

820-0082-B

©1983

 

I've updated the description on my associated Flickr photo accordingly.

 

 

When I get a spare moment (I only had "spare seconds" this evening) I will disassemble my two Mac 512's and check their analog board, solder-side data as well.

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Great. I thought it would be. And this is your 820-0082-C board:

 

630-0102-E: Trace Side of Board.jpg

 

So that confirms when I have some time, I need to photograph my 820-0082-D board for you to add to your detailed analysis of components.

 

Once we get a few more detailed entries on the M0001 Registry, a few more differences are going to emerge for documentation. Specifically with respect to eh 630-0102- numbers. As you pointed out in the above flickr entry, this is possibly an "E" rev. As you noted on your 820-E board, there is what appears to me as a "J" hand-written in the white square next to the 630-0102 which corresponds to all of my late model boards. I agree with you on your 820-C board that the 630-E suffix probably delineates some revision which I suspect is to the components used, versus the design configuration. My operating theory is this: based on the 512K logic board which has a single P/N 820-0141-A, but does double duty as 630-0101- (128K) and 630-0118- (512K), I believe the 820 number refers to the same board which has specific traces and architecture common to either the 128K or 512K. The 630 numbers by contrast use the same board but use different component RAM chips and the 512K board adds some extra resistors and an IC, but is otherwise identical component configuration as the 128K board. I call these macro component changes warranting completely different part numbers (0101 v. 0118). By adding a rev. latter to the 630 macro number, one can account for minor changes to the actual components. In the case of the analogue board, a sturdier flyback transformer, etc. for instance. With that in mind, I suspect that since the 630 number remained the same throughout the analogue board design changes, that the rev. letters refer to the consecutive component changes, meaning there are at least 4 production boards: "B, C, D & E" and between those four major changes, the component list remained substantially the same, though sported as many as 10 minor revisions ("A,B,C,D,E,F,G,H,I & J"). So we may be looking for subtle variations in individual components accounting for up to 10 different revisions across the four revised boards. (i.e. the 820-C board design revision may have added a new resistor or removed one, but the type of resistors used from the first 820-B board to the last 820-E board were accounted for cumulatively by the 630 number revisions whether a resistor was or was not present on the previous or future boards – meaning the 820 design number dictated what was on the board and the 630 component number dictated what the component specifications actually were)

 

Anyway, that's my story until proven otherwise. Then we will have accounted for all of the 120V US domestic boards in excruciating detail and can then start documenting the 220V European boards!

 

Come on guys! Many of you own 220V Macs! Crack em' open!

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Mac128, many thanks for reminding me of that particular photo. I've updated the photo description accordingly. I completely forgot that board is now being used in my Mac512 (the 512 without the HyperDrive). That means I only need to crack open my one HyperDrive 512 to check it's analog board data.

 

I also very much like your theory as to the meaning of the board numbers, and I stand beside you calling on all our friends here at 68kMLA to crack open those Macs and report their numbers!

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I haven't been following this closely and I'm not up to date on the evidence evaluated, also my memory is leaky, so this may be slightly inaccurate or at least wildly incorrect. But...

 

My understanding of the 8xx versus 6xx numbering system was that the 8xx number refers to a circuit board design while the 6xx part number is a functional part number. By circuit board design, I mean, just the board art, not any of the components which may be on it.

 

So, e.g., if you had one circuit board which could be populated differently to make two different functional parts, that circuit board would have a single 8xx number, and a different 6xx number for each way that it might be populated and for each way that it might be sold.

 

I believe that Apple actually did this with the 7500/8500 motherboard. It's the same circuit number and (I think) it has the same 8xx part number in both machines. But it has different 6xx numbers depending on whether the extra video chips for the 8500 are soldered down.

 

Also, if you had two different circuit boards which could serve the same purpose, they'd have different 8xx numbers (different board artwork) but might have the same 6xx number if they were meant to be used for the same function in the same machines.

 

So you can have multiple 8xx boards with the same 6xx number and multiple 6xx numbers being assigned to the same 8xx board. But the distinction (IIRC) is that the 8xx refers to the actual physical instantiation, while the 6xx is a functional part number indicating where that assembly is meant to go.

 

Or I may be full of horse pucky. But that's what I remember, for what it's worth.

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