"J.S. Garrison" ha escrito: > Or the motherboard from an SE FDHD. It has both the 1.4 and 800k available > slots.
This reminds me another thing... According to the Apple //c Reference Manual, the original IWM chip is a DIP chip with two rows of 14 pins each (28 in total), simmilar to the 23xx ROM chips. Inside Macintosh says that the same chip is used in the 400/800 Kb Macintoshes (128, 512/e, Plus, SE, II...). On the other hand, the three Macitoshes I own (a Classic, a Classic II and a PowerMac 6100/60) use the SWIM chip, in a surface mount square package (I'm sorry - I don't know its name) with 11 pins per side (a total of 44 pins). Well, it seems that there is a third disk controller chip - a SWIM but in the 28-pin DIP package of the IWM. Evidence of this is the "drop in" Superdrive upgrade for the original SE: if you can just remove the old IWM and put a SWIM in place, there must be phisicaly and electrical compatibility between them. It seems that later, as Jeff says, when Apple decided to switch to the newer package for the SWIM chip, it modified the SE FDHD motherboard in order to accept both kinds of disk controller chips. Of course, I don't know for sure (the Mac SE service manual I own does not cover the FDHD), but taking all the clues I have at hand and doing a few guesses, I come to this. Greetings, Antonio Rodr�guez (Grijan) <ftp://grijan.cjb.net:21000/> -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
