allbery@NCoast.ORG (Brandon S. Allbery) (12/25/89)
Having finally bitten the bullet and purchased 4MB RAM for my lowly Mac SE, I read Tech Note 179 and then opened the case (not nearly as hard as some have claimed, BTW) to verify. But something is still slightly unclear. TN#179 never came out and clearly stated the meanings of the two (one, in my SE) marked resistors. Reasoning from logic, it would appear that one cuts the resistor marked "256K" to install 1MB SIMMs, and cuts the resistor marked "1ROW" if both SIMM banks are occupied. (This resistor is shown in the Tech Note but is not present in my Mac, which would make sense because it came with 4 256K SIMMs.) While this seems reasonable, I'm quite aware that if I missed something -- and, again, the TN never came out and explicitly stated the meanings of the resistors -- I could end up with a $3000 paperweight; I hope my unwillingness to perform surgery on the inside of my Mac before making sure I know what's going on inside it is understandable. So, would someone please verify that I've figured out what's going on *before* I take wire-cutters to the inside of my Mac? I'd appreciate it no end. Many thanks in advance. ++Brandon -- Brandon S. Allbery allbery@NCoast.ORG, BALLBERY (MCI Mail), ALLBERY (Delphi) uunet!hal.cwru.edu!ncoast!allbery ncoast!allbery@hal.cwru.edu bsa@telotech.uucp *(comp.sources.misc mail to comp-sources-misc[-request]@backbone.site, please)* *Third party vote-collection service: send mail to allbery@uunet.uu.net (ONLY)* expnet.all: Experiments in *net management and organization. Mail me for info.
jdhill@bbn.com (Jack D. Hill) (01/11/90)
In article <1989Dec24.204916.442@NCoast.ORG> allbery@NCoast.ORG (Brandon S. Allbery) writes: >Having finally bitten the bullet and purchased 4MB RAM for my lowly Mac SE, I >... >SE) marked resistors. Reasoning from logic, it would appear that one cuts the >resistor marked "256K" to install 1MB SIMMs, and cuts the resistor marked >"1ROW" if both SIMM banks are occupied. (This resistor is shown in the Tech >Note but is not present in my Mac, which would make sense because it came with >4 256K SIMMs.) You are correct. Cut out the resistor marked "256K". It should be left in only when ALL the SIMMs installed are of the 256K variety. And for anyone who is interested, if you want to upgrade to 2.5 Meg, cut the resistor and swap 1 Meg SIMMs for the 256K SIMMs in sockets marked "SIMM 1" and "SIMM 2" (leaving in the 2 - 256K SIMMs in sockets 3 & 4). This goes for both the SE and the PLUS; despite the fact that the SIMM sockets are positioned differently. Jack
briand@tekig5.PEN.TEK.COM (Brian Diehm) (01/11/90)
>Reasoning from logic, it would appear that one cuts the resistor marked "256K" >to install 1MB SIMMs, and cuts the resistor marked "1ROW" if both SIMM banks >are occupied. See why you should NEVER use logic? >I could end up with a $3000 paperweight; I hope my unwillingness to perform >surgery on the inside of my Mac before making sure I know what's going on >inside it is understandable. Uh, well, if you insist... Cut ONLY the resistor marked 256K. DO NOT cut any other. (However, if you DID cut too many, send me the useless $3000 paperweight - I would LOVE to solder back a resistor and get a free SE... ;-} ) This is true whether you replace only two banks or all four. If you replace only two banks, put the 1Meg parts into the back two SIMM slots. Simple as that. Hint: Cut only one end of the resistor and angle the body about 45 degrees. This way, if you ever change your mind, it takes only seconds to solder the resistor back. -- -Brian Diehm Tektronix, Inc. (503) 627-3437 briand@tekig5.PEN.TEK.COM P.O. Box 500, M/S 39-383 Beaverton, OR 97077 (SDA - Standard Disclaimers Apply)
kaufman@Neon.Stanford.EDU (Marc T. Kaufman) (01/11/90)
In article <1989Dec24.204916.442@NCoast.ORG> allbery@NCoast.ORG (Brandon S. Allbery) writes:
-Having finally bitten the bullet and purchased 4MB RAM for my lowly Mac SE, I
-read Tech Note 179 and then opened the case (not nearly as hard as some have
-claimed, BTW) to verify. But something is still slightly unclear.
- ...So, would someone please
-verify that I've figured out what's going on *before* I take wire-cutters to
-the inside of my Mac? I'd appreciate it no end.
The first rule is to (almost) never do anything irreversible. To "remove" a
resistor -- cut ONE END lead, in the middle. Then you can tack-solder it back
together if you change your mind.
Marc Kaufman (kaufman@Neon.stanford.edu)