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Sad Mac 040002

Quadraman

Well-known member
So I replaced the power board in my 128k and I am now getting Sad Mac 040002 at bootup. From what I can gather there is some bad memory on the motherboard that causes this. Does anyone here know how to replace the chips? I can't test the chips to find which are bad or solder so I need someone who can do it for me.

 

Mac128

Well-known member
The error code theoretically tells you exactly which chips to replace. I don't have the codes handy at the moment but they can be found almost anywhere on the net. I've checked out a few 128K boards and have pinpointed exactly which chips are bad ... it's a place to start in any event, even if it is not 100% accurate as some have suggested.

Simply desolder the chips and replace them with good chips.

Out of curiosity, are these Apple branded chips? I found that almost without exception, the boards with failed RAM (which I attribute to bit-rot), are the Apple chips. Way to go Sculley, cutting those corners to increase that bonus!

 

Nathan

Well-known member
That sounds like a safe bet according to my book (MacWEEK Upgrading and repairing your mac). The tables are a little hard to decipher, but i'm guessing it's a class code 4 (Memory Test - Mod3 Test) which "Identifies bad chips". Possibly: Data Bit 10, Location G7. Sub Code Bits 0400 if that makes any sense to anybody? It looks like an address error (0002 Address Error)? On this page, http://en.wikipedia.org/wiki/Macintosh_128K, there's a motherboard picture for the 128K -> http://en.wikipedia.org/wiki/File:Macintosh-motherboard.jpg. It looks like, from my limited knowledge, you should replace the chip that is located at Column G, Row 7 in the picture. The chip has the labels '8428' and 'MT4264' on it in the picture.

 

johnklos

Well-known member
You might as well remove all the chips and put in some good sockets. You can then choose between having 128k of memory with 64k x 1 chips or 512k with 256k x 1. It was a common upgrade back in the day.

 

Mac128

Well-known member
and a lot more work!

I would definitely put a socket in for any chip I removed, but it's a big job to do it unnecessarily for all of them, and might cause more problems than it's worth.

At this stage of the game I would recommend getting a separate 512K board rather than upgrading a stock 128K given their rarity. In addition to the larger RAM chips you also have to install a mini-mux, which at this point likely has to be fabricated from scratch. Permanent modifications are required to the logic board which are not always successfully reversed. I've inquired about adding a simple toggle switch in the past, to switch the mini-mux in or out of the circuit, but simply haven't had the opportunity to do it. Theoretically you can install 256K chips and they will behave as 128K without the additional decoding circuitry.

 

Quadraman

Well-known member
I've seen stock 512k boards for as low as $50 so for all the work of socketing the chips on a 128k board plus the cost of the sockets and new chips it's better just to buy the whole board. I've actually been thinking of just getting a 512k board and putting that in until I can find someone who knows how to solder who can replace the bad chip on the 128k board. I also didn't want to socket the chips because I intended to resell this if it didn't need a lot of expensive work to get it running and the value would be ruined with sockets added.

 

Mac128

Well-known member
Hmmm. Well if you intend to sell the 128K, then yes for some collectors, sockets upset the authenticity. The reality is, it should have had sockets, but Jobs nixed it. Any one of us on this board would LOVE to get a sockets 128K or 512K. Or hell, any Mac!

Soldering on a 128/512K circuit board is one of the easiest soldering jobs you'll ever see. Get yourself an old circuit board and a soldering iron and learn the basics. Otherwise, owning vintage Macs will eventually cost you a lot in repairs.

 

Mac128

Well-known member
Here's a picture that at least highlights, if not proves my point. An original mid-prodcution 128K logicboard with Apple branded RAM chips. Two of them had to be replaced last year according to the seller. Notice, he's wisely replaced them with sockets. But I have a stack of failed 128K boards all with Apple-branded, Sad Mac RAM error codes in need of replacement. Yet I have never seen a third party OEM RAM chip that's failed. Could just be my experience but I think it is more than coincidence. Apple must have gotten quite the deal on some really cheaply made RAM, allowing them to make even more money on the already overpriced 128K (thank you John Sculley).

lb1g.jpg


 

oldappleguy

Well-known member
I remember a trick that I tried. With the board out of the case, press a memory chip over the chips on the board one at a time

Make sure that the pins only touch the corresponding pins, and orient the chip the same way. Start the Mac. If you get the error code move to another chip until you find the bad one.  

 

Mac128

Well-known member
That's a very good tip. Though it does require constructing an extra long cable between the logic board and analogue board. It also doesn't help identify more than one bad chip at a time. However, I imagine that the error code will change when you find on or more of the bad ones, eventually identifying all the bad chips.

This board pictured is typical of the error codes I've seen which almost always specify more than one chip. In this case, I'll bet both of those chips had both failed from the time it was last used to the time he fired it up again.

 
Notice, he's wisely replaced them with sockets. But I have a stack of failed 128K boards all with Apple-branded, Sad Mac RAM error codes in need of replacement. Yet I have never seen a third party OEM RAM chip that's failed. Could just be my experience but I think it is more than coincidence. Apple must have gotten quite the deal on some really cheaply made RAM,
Thanks 128, I'm the one who did the repair, I traded my brother for a Bad Lisa board:) He's pretty good at that stuff but he had fried his new chips because he refuses to use sockets (just a little heat over a 15w iron destroys those things), in fact I have the board back because after you would start it 7 or 8 times (and that is almost to a T) you get an error code for those chip locations, I believe it is because of the different chip speed, this has happened on probably a dozen of the boards I have repaired? In theory the RAM will only operate as fast as the slowest chip, HOWEVER, when I have used the correct 200ns 4264 equivalents I get no error codes(And this is in probably over 30 boards)? the error codes go away after a restart on the the boards where I used the 100ns and 150ns chips, and they would once in a very great while generate a system error when using MacPaint, but not with the other programs. The chips I had been using were 100ns and 150ns, the 150ns seem to generate less error codes than the 100ns (probably 10 to 15 starts). As far as Apple cutting corners I would have to disagree, I have seen Apple branded chips from three manufactures, I believe Apple simply screen sprayed these chips when they received them, I have seen at least two logicboards with 200ns chips from two different manufacturers (MT4264 and 3764) that are Apple branded? One last thing about the 040002 code, MAC128 is right .........for some reason every time I have an error code there or at G7, the F7 or G8 chips are kaput? As far as the test using chips piggybacked onto "supposedly" failed chips, I have heard this from many techs as far back as 1983, but in my experience it does not work. if you sandpaper the legs of the chip in question and the chip you piggyback, and squeeze them really tight, you might get a connection that will suffice for data transfer (and yes I know what folks will say about the clip on memory upgrades) , BUT, again in my experience it simply does not work, I had numerous chip failures only to go through all the banks and find that the chips I had been using for testing were bad, OR, the chips I had been using were good, but not making a good connection, sockets are the only way to go. I also believe that even if you piggyback the chip in question, it is still cycling data through (the old chip) and will still show the same error? I have ran into this before.

 

H3NRY

Well-known member
There used to be arguments among memory upgraders about whether to use sockets or not. There are some 128K boards which just don't have enough juice to drive the extra capacitance sockets add across address lines (about double that of a chip soldered directly to the board). Generally, I like socketed chips for ease of repair, but I found too many early Mac boards simply got flaky, so I quit using sockets. Desoldering & removing all the sockets you've just installed will discourage you fairly quickly. I also found the NEC ceramic chips I preferred for upgrades and repairs simply never failed, and were quite safe to solder in place.

One upgrader claimed that his boards using socketed chips would be upgradeable to 2MB using 1 Mbit chips when they became available. Those of us who could count to 16 pointed out to him that with 16 pins, the max size chip you could have was 256K, but he never understood, and was very surprised when 1Mb chips turned out to have 18 pins, and didn't fit his sockets. xx(

 

QuicksilverMac2001

Well-known member
Hm. I have a post September 10th 128k-model board in my Macintosh 128k (but with an original Macintosh rear bucket), Apple branded RAM chips, stock 128k amount even, not a single chip ever replaced,(if I felt like opening it up I would and will if you really need proof) but it's gotten a steady stream of use from all of it's owners, and so with a significant amount of reinforcement from God, it still chimes, gives a Happy Mac, and finishes booting up almost every time (corrupted software on one particular boot floppy that later went sour being the only exception, indeed the Sad Mac code was the much more benign 0F starting sequence even.) Switched to my other boot floppy options, been once again back to chimes, Happy Mac showings, proper boot ups, and proper operation from desktop to disk ejection (using System 1.1 Finder 1.1g) and shutdown.

My 128k must be the only stock one (or at most one of a pathetically small number) with all matching Apple logo RAM chips and proper operation. I invested in 4 major peripherals for it from evilBay I was so thrilled with it's continued "just working".

I wonder, given the horrible reliability rates of stock 128k boards with Apple branded RAM chips, if that makes my 128k worth more than one with a pre-September 10th logic board with failed or replaced non-original RAM chips.

It does have screen burn-in, and some minor scratching, but this topic has put some really wild thoughts in my head that I want to make sure are wild.

 
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