ziggy+@andrew.cmu.edu (John Salmento) (03/03/89)
Hi, I have a couple of questions about Mac simms. I removed two 256K simms from my Mac Plus, when I upgraded it to 2.5 MB. Is there a way to tell the speed of these simms by the age of the Mac Plus, or by looking at the simms? Are Mac simms and IBM simms interchangeable as long as the simms are fast enough? Is it possible to use Mac simms in a 512KE, ie. does the 512KE macs have simms slots? Thanks, John Salmento ziggy+@andrew.cmu.edu
venkatap@amelia.nas.nasa.gov (Ethiraj Venkatapathy) (06/16/89)
Will some kind soul on this net explain the following terms:
1) DIP SIMM
2) SOJ SIMM
3) Surface Mount SIMM
Which of these is better and at what speeds (in ns)? I need this
information specifically for a MacII/IIx/IIcx. Please post or
email to me at venkatap@amelia.nas.nasa.gov.
Thanks in advance.dwells@Apple.COM (Dave Wells) (06/16/89)
In article <2289@amelia.nas.nasa.gov> venkatap@amelia.nas.nasa.gov (Ethiraj Venkatapathy) writes: > Will some kind soul on this net explain the following terms: > 1) DIP SIMM > 2) SOJ SIMM > 3) Surface Mount SIMM > Which of these is better and at what speeds (in ns)? I need this > information specifically for a MacII/IIx/IIcx. Please post or DIP = Dual Inline Package SOJ = Small Outline, J-mount lead Surface mount is the technology of mounting components _onto_ a circuit board instead of through. J-mount leads are designed with this purpose in mind. They're placed on the prepared circuit board with the 'J's sitting on contact points and are then attached using various soldering/cementing methods. The idea is simpler automated assembly and board design simplification, etc. Dual Inline Package conponents use the original "drill a hole and poke the pins through" idea. You've probably seen them. It's just a chip, or what- ever component, with a row of pins pointing down from each side. Poke 'em through holes in the circuit board and solder. Their package (case) is larger than that of SOJ components, and this accounts for the restrictions on which machines they work best in. Of course, they're nicer than SOJ components when it comes to wire-wrap! ;-) A Surface Mount SIMM is just a Single Inline Memory Module that uses some form of surface mount technology to attach the RAM. Beware pseudo-surface mount in the form of DIPs with the pins chopped off at the knees! They still use the larger package DIP ICs and won't fit everywhere. You may also encounter SIMMs using PLCC RAM. (that's Plastic Leaded Chip Carrier) They have a slightly smaller package than the DIP, but are essentially the same as far as fitting in Mac's is concerned. For any of the Mac II family you can use any of this RAM so long as it's rated at 120ns or faster (smaller # is faster). The Mac II's have plenty of room so there's really no best _unless_ you plan on moving the RAM to a Plus or SE later. (who knows? When we all use 4MB SIMMs in our II's we'll have to find a use for all those 1MB SIMMs.) If one must be better than the other, real surface mount is generally considered to be better because of its smaller size and the resulting increase in applicability. -Dave -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Dave Wells, Apple Computer, Inc. MS: 37-O (408) 974-5515 Mail: dwells@apple.com or AppleLink d.wells or GEnie D.WELLS These opinions may be nothing more than the ramblings of a fatigued tinkerer -=-=-=-=-=-=-=-=-=-=-=-=- There's one big difference between genius and stupidity. Genius has limits. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
kn0j+@andrew.cmu.edu (Kenneth Blake Nerhood) (11/17/89)
I have an SE with 1MB of memory and a 20MB hard drive. I would like to upgrade my memory. Questions (1) I have read the postings about where to buy chips. When I order the chips, do they come on a board that I install in my mac or do they come loose? If they come loose, do I need to order get a board? Where and what should I get? (2) Once I have the new memory, do I have to have a dealer install it or can I do it easily? If I can do it myself, what is the procedure that I should follow. Thanks in advance for the help. Ken Nerhood Carnegie Mellon
roy@phri.UUCP (Roy Smith) (11/17/89)
In <cZMlnuG00WB404Z0cv@andrew.cmu.edu> kn0j+@andrew.cmu.edu (Kenneth Blake Nerhood) writes: > When I order the chips, do they come on a board that I install in my mac > or do they come loose? If you order chips, you get loose chips. If you order SIMMs, you get chips mounted on a little PC board that you just plug in. I'm not 100% what SIMM stands for, but I assume it's Single Inline Memory Module, by analogy to DIP (Dual Inline Package). The vast majority, if not all, of the ads you see in MacWeek and the like are for SIMMs. > do I have to have a dealer install it or can I do it easily? I'll only address the technical issues -- there are also problems of warranty violations and the like of which I know little. Plugging in a SIMM is pretty trivial -- if you can plug in a PC board, you should be able to plug in a SIMM. You put the edge with the contacts into the socket and then gently push it over to one side until the plastic clips engage the holes in the SIMM PC board. If you need to remove a SIMM (for example, to replace a 256k module with a 1 Meg module) that's a little bit more complicated. You have to be careful to release the plastic clips built into the socket without breaking them. I use a small flat bladed screwdriver to pry up the clip on one side and use a finger to rotate that end of the SIMM out of the socket enough so that when I release the clip it won't snap back. Then I do the other end. If I'm removing a whole bank of SIMMs, I find it more convenient to do one end of all the modules then go back and do the other end of all the modules than to do both ends of one module before moving on to the next. None of this will make any sense until you actually have a SIMM socket in front of you and see what it looks like. Another complication is getting the case open. If you have a II series machine, it's easy; the lid is designed to come off by just releasing a couple of clips and maybe a phillips head screw. Note: on the plain II, it is normal for it to sound like something is breaking when you take the lid off! On the II-Cx, it's a somewhat better design which doesn't make as much noise. On a Plus or SE, you have to remove 4 or 5 screws. These screws have TORX heads requiring a possibly-hard-to-find TORX screwdriver. Even worse, two of the screws are hidden under the handle and require a longer-than-normal shaft TORX driver to get at them. Two are in obvious places and I think one is hidden under the battery cover. Once you have unscrewed it, you are still faced with prying the tightly-fitting body halves apart. Probably your best bet is to ask your memory supplier if they can also sell you a special "Mac Opener" which is a combination long-shaft TORX driver of the appropriate size and a sort of Mac-specific crowbar. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 {att,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@alanine.phri.nyu.edu "The connector is the network"
wilkins@jarthur.Claremont.EDU (Mark Wilkins) (11/18/89)
In article <4129@phri.UUCP> roy@phri.UUCP (Roy Smith) writes: >In <cZMlnuG00WB404Z0cv@andrew.cmu.edu> kn0j+@andrew.cmu.edu (Kenneth Blake >Nerhood) writes: > >> do I have to have a dealer install it or can I do it easily? > > I'll only address the technical issues -- there are also problems >of warranty violations and the like of which I know little. Plugging in a >SIMM is pretty trivial -- if you can plug in a PC board, you should be able >to plug in a SIMM. You put the edge with the contacts into the socket and >then gently push it over to one side until the plastic clips engage the >holes in the SIMM PC board. If you decide to install your own SIMMs, PLEASE, PLEASE use proper static protection. The circuitry is extremely sensitive to static discharges which you may never notice until you boot your machine and get a sad mac, and this applies to the Mac internals as well as the RAM. The solution to this problem is either to wear a static bracelet, usually an elastic bracelet with a metal piece at the wrist, which has a wire which you connect to the case of the machine so that your wrist is grounded, or to touch the power supply's metal case with your working hand and hold onto it with the other hand while you work. Sound like a hassle? It is. It's the main reason that doing this will void your warranty. And this sort of care is what you pay for when you get a dealer to do it. If you routinely do this sort of work or you know someone who does, then go for it. I just installed 4 megs of RAM yesterday. If you feel even a little uncomfortable, then consider that it might be better to pay someone $50 and be safe rather than lose $500 worth of memory or $5000 worth of computer. -- Mark Wilkins wilkins@jarthur.claremont.edu P.S. Followups to comp.sys.mac.hardware