That moment when...

pocketscience

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... you've spent a good few hours preparing to record something for work featuring your 128K Mac... and then...
Screen Shot 2022-08-03 at 9.07.53 pm.png


...the DRAM chip at G8 goes and takes a dive...

I don't have a handy supply of 64K bit DRAM chips floating around unfortunately... well, apart from a few restored C64's.. hmm... 🧐
 
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Patrick

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i had a sad mac error on my 128k that didn't match any of the errors.

...

it took me way too long for me to admit that it meant that it was reporting 2 bad ram chips. .. and i only realized that when i watched a Branchus video where he fixed a mac 128k with like 2 or 3 bad chips.
 
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pocketscience

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And I found a comprehensive book on Sad Mac errors and other errors that happen on the Mac. Has anyone seen or read this book?

Hardly comprehensive. I hadn't read that one before, but these few snippets from looking up Sad Mac codes in it hardly inspire confidence in solving a real problem... (underlines are mine)

Sad Mac codes decoded If you already read Chapter 4, which discusses system errors, you know that I don't recommend wasting much time trying to interpret the system- error ID messages. The same is true for the string of letters and numbers that you find below the Sad Mac icon
Right, so ignore the error and press on. Got it..

The most common hardware cause for the appearance of the Sad Mac icon is a problem with memory chips (SIMMs or DIMMs), especially if the Sad Mac first appeared soon after you added memory to your machine. Some error codes specifically indicate a memory-module problem. In some cases, they even suggest the slot in which the problem memory module is located (though I won't be going into this level of detail here).
So here's a book that literally has the words "Sad Macs" in the title, but the author can't be bothered going into the details. Sweet... 🤦‍♂️
 

retr01

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Hardly comprehensive. I hadn't read that one before, but these few snippets from looking up Sad Mac codes in it hardly inspire confidence in solving a real problem... (underlines are mine)

Ah. So, it's just a dumb reference book with a lot of fluff, then?

Right, so ignore the error and press on. Got it..

It sounds like the author doesn't encourage critical thinking.

So here's a book that literally has the words "Sad Macs" in the title, but the author can't be bothered going into the details. Sweet... 🤦‍♂️

Maybe it's because the author doesn't want to waste time other than fluffing the reference book up? :sneaky:

Hey @pocketscience, thank you for pointing it out. :)
 

Patrick

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i have this book!

and yes. its not that great. it is BIG and it is written in a very laymen style. example is exactly right. it will tell you what sadmac error code means bad memory. but it doesn't tell you how to decode the address of the bad memory.

I'm also not sure which type of mac it assumes you have. but its soo generic i guess it could mean any mac.
 
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retr01

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written in a very laymen style. example is exactly right. it will tell you what sadmac error code means bad memory. but it doesn't tell you how to decode the address of the bad memory.

I'm also not sure which type of mac it assumes you have. but its soo generic i guess it could mean any mac.

That makes sense. So, there are probably not that many written books that go further than layman and surface stuff?
 

Crutch

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Well … there are! But they would be books for developers. If you want to know what you should do when you see a system error ID = 02, the real answer is almost always “debug your code”. The books to teach you how to do that are programming and Toolbox how-tos, mainly, but there’s almost never a quick fix to someone else’s code for a user/tinkerer no matter how savvy. So this author isn’t wrong (though his title is very misleading).

For Macs that won’t boot, the Larry Pina books are the best answer most of the time.
 
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retr01

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Well … there are! But they would be books for developers. If you want to know what you should do when you see a system error ID = 02, the real answer is almost always “debug your code”. The books to teach you how to do that are programming and Toolbox how-tos, mainly, but there’s almost never a quick fix to someone else’s code for a user/tinkerer no matter how savvy. So this author isn’t wrong (though his title is very misleading).

Got it. :)

For Macs that won’t boot, the Larry Pina books are the best answer most of the time.

Awesome! :)
 

Patrick

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For Macs that won’t boot, the Larry Pina books are the best answer most of the time.
i really like his books. they are of the correct size. (not giant and useless) and what they tell you is very helpful.

His compact mac book even talks about useful upgrades as well as actual knowledge of how to fix things. Born out of years of somebody fixing the macs. I highly suggest people trying to get their collection of retro macs working to get his books.

..

i still find online resources to be more helpful tho in a lot of cases. and i hope we as a community can build up our resources tab with stuff.
 
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JDW

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... you've spent a good few hours preparing to record something for work featuring your 128K Mac... and then...
View attachment 7326

...the DRAM chip at G8 goes and takes a dive...

I don't have a handy supply of 64K bit DRAM chips floating around unfortunately... well, apart from a few restored C64's.. hmm... 🧐
I take it you have the RAM chips with the Apple logo printed on them? Those seem to be the worst in terms of reliability for some reason.
 

retr01

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Speaking of worse quality in terms of ICs, I find it interesting that today, Apple has dramatically improved the quality of the Apple Silicon chips they designed in-house and partnered with TSMC in Taiwan to manufacture those M1 and M2 chips. Back then, Apple squandered and came up with questionable quality ICs aside from Japan's ICs, which were much better. Now that Apple is a $3+ trillion company makes its dark manufacturing history laughable that on the consumer side, back then, people were wowed as engineers on the other side facepalmed. Who messed up? The executives. Steve Jobs was right - the executives, particularly John Sculley, flopped.

On the bright side, playing on those vintage Apple computers is more fun now. I know there are challenges, but imagine if we reverse engineered RAM chips and have those made with better quality? The day will come when we can do that in the comfort of our homes with PCB and 3D printing technology and continue to have fun with those old Apple computers.

Let's not have those lousy executives, including Jean Louis Gassee. He screamed and yelled at some Engineers and demanded certain things that, in turn, compromised the quality and put a dampener on our vintage Apple fun.

Oh, sorry, I was mumbling nonsensically. :oops:

Anyway, yeah, I think reliability is subjective. I mean, it depends on age and other factors, right? I saw a YouTube video where one person tried to save an Atari computer in vain. It was restored, running fine, until one day some of the chips started to fail. That person realized that some vintage computers reach a point where it's better to retire them.

That makes me wonder, can we have RAM and other necessary chips "reloaded" like reloaded mobos?
 

pocketscience

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I take it you have the RAM chips with the Apple logo printed on them? Those seem to be the worst in terms of reliability for some reason.
Yup, original DRAM chips.. 35+ years of reliability then *poof* - outrageous! :) Anyway, here's the culprit. I struggled to get him out (ground plane!) so ended up snipping the GND leg and removed rest with flux and wick.
IMG_2277.jpeg

Put a socket in and a replacement NEC brand 64Kbit 150nS chip that I found in my piles of C64 stuff. Powered straight up without issues. Yay.
 
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retr01

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Yup, original DRAM chips.. 35+ years of reliability then *poof* - outrageous! :) Anyway, here's the culprit. I struggled to get him out (ground plane!) so ended up snipping the GND leg and removed rest with flux and wick.

Put a socket in and a replacement NEC brand 64Kbit 150nS chip that I found in my piles of C64 stuff. Powered straight up without issues. Yay.

Awesome, @pocketscience! :D(y)

Is the middle chip "HM4864P-3" the replacement NEC brand or the original? If the NEC brand RAM chip is not pictured, can you please take a picture of that? 🤓