Classic II logic board differences

[stevep]

After looking through all the topics in this forum, I don't see that this has come up before; my apologies if it has.

I have two logic boards, both marked as Classic II and dated 1991 - one numbered 820-0401-A with 4 ROM chips, the other numbered 820-0626-B with 2 ROM chips. The first one (4 chips) has the blue wire stuck on it as mentioned in some posts.

Does anyone know what the difference(s) are and when the change happened? One of the machines these came from was made October 1991 (4 chip) and the other October 1992 (2 chip).

Even Larry Pina's "Mac Classic & SE Repair and Upgrade Secrets" does not acknowledge the 2 chip board. It shows board 820-0401-A having 4 ROM chips.

 

[beachycove]

Is the change perhaps associated with when the speaker was moved? That would be easier to pin down to a specific date.

 

[stevep]

Is the change perhaps associated with when the speaker was moved? That would be easier to pin down to a specific date.

In these two, the speakers are located in the same place - front lower edge of the analog board. One has holes in the case bucket for the speaker and the other doesn't. Where did the speakers get relocated to?

 

[Mac128]

Where did the speakers get relocated to?

They didn't. I don't know what he's talking about.

I have heard that the CLassic II had two different ROM configs, but I thought I read that in Pina's book. Guess not. The Apple Service manual makes reference to it that the logic board can have two or four ROMs, and that they are otherwise identical. It also identifies the different logic boards as the same part number. Apple's own Developer Manual specifically lists the 4 ROM chips (see pg. 13).

Aside from manufacture date, were your Classics built in two different locations? There could be some localized reason for the logicboard change by manufacturer. Obviously the two chip ROM and the speaker perforations are in the later Classic II, which obviously coincides with some update in the design. Pina does reference the speaker addition where he provides the perforation template for retrofitting a Classic with the holes. So likely it all occurred at the same time. CORRECTION: Just looked at the Pina book, which is copyrighted 1993. Since your Classic II has a manufacture date of 1992, and Pina's book only mentions the 4 ROM chipped logic board, but also the speaker perforations, the case modification happened before the logic board change, or Pina did not think it significant enough to comment on. I find the SE/Classic book on the whole lacking quite a bit more detail than the original Plus book. So the Classic II came out in late '91. The released as the Performa 200 in September 1992, so that's probably when the speaker grille appeared. The logicboard may have changed then too and Pina simply did not discover it in time to revise the book (not having opened one), though the case perforations would have been pretty obvious. Or it appeared even later in the year.

 

[beachycove]

There were indeed two different Classic II cases, the difference between them being the speaker location. Whether there was a corresponding change in the logic board configuration I do not know.

 

[stevep]

Both built in Singapore, and both boards indicate they were assembled there too.

Pina's book lists the part numbers for the 4 chip ROM board only which is odd as it's dated 1993 which is after these machines were made. Part numbers on the two chip ROMS are 341-0261 and 341-0257 and made by Samsung.

 

[stevep]

There were indeed two different Classic II cases, the difference between them being the speaker location. Whether there was a corresponding change in the logic board configuration I do not know.

I have 4 Classic II's. Only difference I can see is one did not have holes for the sound to pass through. Where was the speaker located in the one you refer to?

 

[Mac128]

There were indeed two different Classic II cases, the difference between them being the speaker location. Whether there was a corresponding change in the logic board configuration I do not know.

Beachycove, there were indeed two cases, one without the speaker grille and one with. There were only two Classic series Analogue boards and the speaker position was the same in both. Therefore, the placement could not have changed in the Classic II. Where are you getting your information?

 

[Mars478]

My Classic two has the speaker grille but the speaker as far as I know has not moved in either iteration of Classic II!

 

[beachycove]

Then the only change was that holes were drilled in the case. I had assumed that the case without holes in the side must have had a speaker grill elsewhere, and so that the speaker had been moved. Mea culpa. I repent in sackcloth and ashes.