Path: utzoo!utgpu!watserv1!watmath!att!mcdchg!laidbak!ism.isc.com!uunet!snorkelwacker!usc!ucsd!dog.ee.lbl.gov!nosc!crash!alen From: alen@crash.cts.com (Alen Shapiro) Newsgroups: comp.sys.mac.hardware Subject: Re: Memory upgrade for Mac Plus (how-to reply) Keywords: references wanted Message-ID: <5143@crash.cts.com> Date: 19 Oct 90 14:58:01 GMT References: Organization: Crash TimeSharing, El Cajon, CA Lines: 69 In article masticol@lento.rutgers.edu (Steve Masticola) writes: > >Does anyone have a reference (in one of the Mac magazines or books, >perhaps) on how to upgrade the memory of a Plus? I need to know both >the procedure and what type of SIMMs to buy. > >Thanks, >- Steve (masticol@athos.rutgers.edu) I buy 100ns by 8 (or faster) from the chip merchant in San Diego, the plus does not use the parity (9th) bit so *8s should be ok. (tel: 619-268-4774) here's an old posting of mine, reposted in case there are others interested - the only addition I've been advised to put in is a warning to BEWARE OF THE TUBE...try not to break it or to accidentally force a screwdriver into the rubber protection while earthed (boy - some accident :-() 1) buy an earth strap (folklore but who dares go against that!!), a long handled allen-key of the type that will fit into the "star" screws on the mac (apple will sell you a "star" key for about $50 - the allen key can be bought for about $5) and a case cracker (the case cracker can be done without if you dare to face the mac on its screen and shake it as you pull up on the case with ALL 5 (yes 5) screws undone (2 screws under the handle, 2 in plain sight and 1 UNDER the battery flap (crafty apple)). 2) undo screws 3) pry off programmer buttons (they will crease the mother-board protector paper). 4) pull case from rear of machine with screen face down (case cracker comes in useful here) the plastic/foil mother board protector may fall off at this point - take it off anyway and save for reassembly. 5) mother board is the board nearest the base of the machine. Pull off 2 cables attached to mother board (1 = floppy 2 = power - note which way they should go back on (no harm in being careful)) 6) carefully slide out mother board towards the rear of the machine (NOTE if you have an accelerator board you won't want to slide this board anywhere since it will probably scrape off the add-on board (not much clearance)). 7) with the board chips up and the external plugs nearest you (rear of the board), the simms are far away from you mounted at an angle to the horizontal with side-catch fasteners. Remove the 2 simms nearest you (the 2 nearest the center of the board) 8) replace these with new simms (chip side up, board notch same as all the other simms). 9) locate and remove the resistor jumper marked 256kbit which will be towards the right side of the board if the previous orientation (back towards you) is maintained. The jumper is about 1/4 of the board length away from you. 10)All done - slide mother board back in, replace plastic/foil protector, connect 2 leads, slide case back on (careful - no force is necessary here if it seems to stick then find out why and correct), replace screws (you should still have 5!!), replace programmer switch and power-up. NOTES: 1) do not be alarmed if 10-15 secs go by before the grey screen becomes the smiley face - testing 2.5Mbytes take a while 2) simms must be fitted in like pairs - start with 4*256k = 1M, upgrade to 2*1M + 2*256k = 2.5M or 4*1M ( = 4M). I don't believe any other combinations are legal. 3) replacing memory is fun - it'll take 10 mins or less when you've had some practise. 4) if the smiley face is bordered by a black screen then you forgot to remove the resistor jumper (or snipped the wrong one - woops). (the former should not cause any damage, the latter is anyone's guess). 5) I replaced my memory while wearing an earth strap I suggest you do the same just in case the folklore is soundly based. DISCLAIMER - (guess what comes here). Sorry if I got it wrong guys - I don't believe I did - I've done it a load of times now with no problems but I won't be responsible for problems due to following these instructions which are given in good faith etc etc.