Macintosh SE Sad Mac: Bad RAM chip identification possible?

[JDW]

I've been testing my inventory of 1MB RAM SIMMs using my Mac SE Reloaded machine, and with one particular set of SIMMs, I get a Sad Mac at cold boot showing these 2 lines:

00000004 <— "Bank A"
00004000 <— Failed bits...

AABBCCDD​

​

AA = bits 31-24
BB = bits 23-16
CC = bits 15-8
DD = bits 7-0​

Failed SIMM (8 Chips marked SANYO LC321000J-10):





There's another SIMM just like it which tests fine when used with my known good RAM. So it's not a matter of that particular RAM type not working in an SE.

QUESTION: As per the above, can it be determined which IC or ICs are in need of replacement?

 

[JDW]

Hey @JDW, do you think you could replace that particular IC rather than the whole SIMM? I wonder which is more cost-effective - the failed IC or the entire SIMM to replace?

EBAY shows four 1MB SIMMs for a good price until shipping to Japan is added

4x 1MB 30-Pin 80ns Non-Parity FPM Memory SIMMs 4MB Apple Macintosh SE Plus II | eBay

Apple Macintosh SE Plus II.

www.ebay.com

So I don't really know.

 

[retr01]

EBAY shows four 1MB SIMMs for a good price until shipping to Japan is added

So I don't really know.

Well, how about seeing if you can find that IC? Unobtainium?

 

[retr01]

INTRODUCING

THE RAM SIMM TESTER!

 

[JDW]

Well, how about seeing if you can find that IC? Unobtainium?

It might be possible to find. It's just not high priority for me right now since I have other good and working 1MB SIMMs. But I can come back to this at anytime, get a new chip and see if that works.

Pretty amazing animated GIF you made there! That must have taken some serious time to create! But please know that @YMK deserves all the credit. By the way, if you don't already have a MacSD, you ought to give one a try.

 

[retr01]

I can come back to this at anytime, get a new chip and see if that works.

That'd be cool!

Pretty amazing animated GIF you made there! That must have taken some serious time to create! But please know that @YMK deserves all the credit.

Thank you! It does take serious concentration and effort, yes. Sometimes quick. Other times, not. Depends on the circumstances and work involved.

Oh definitely! @YMK deserves all the credit for the fabulous idea and for helping you, @JDW. I want to point out that many things I noticed we do here on TinkerDifferent are a group team effort, too. Everyone contributes in some way.

What do you think, @YMK? Did you like the animation?

By the way, if you don't already have a MacSD, you ought to give one a try.

Yes, @YMK's MacSD is on my list.

 

[YMK]

What do you think, @YMK? Did you like the animation?

It's very amusing, and like JDW said, it looks like you spent a lot of time on it.