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From: info-mac@uw-beaver
Newsgroups: fa.info-mac
Subject: Re: DIY Mac Fattening: DDJ Jan 84
Message-ID: <315@uw-beaver>
Date: Sun, 30-Dec-84 19:17:52 EST
Article-I.D.: uw-beave.315
Posted: Sun Dec 30 19:17:52 1984
Date-Received: Mon, 31-Dec-84 03:18:44 EST
Sender: daemon@uw-beaver
Organization: U of Washington Computer Science
Lines: 43

From: dlc@LANL (Dale Carstensen)

> - Has anyone tried this upgrade yet?  Did it go smoothly?
Yes.  Mostly.  The first hard part was getting a Torx T-15 screwdriver with a
long enough shaft.  I took a Master Mechanic magnetic-interchangeable-tip model,
modified the T-15 tip with part of a magnetic extender and part of a 1/4-inch
bolt with a welder to make the T-15 tip about 4 inches long.
The second hard part was discovering (I had read it earlier, I'm sure, but
forgotten) the fifth screw is in the battery case.
The third hard part was getting a cutter that will go between the pins on the
64K memory chips.  I did some grinding on a cutter I had, but good precision
diagonal cutters would be better.
I had some strip socket pins I put in, so I was able to get by without taking
all the old pins out, but if I did it again, I would do it the DDJ way.
I also had the A.P.P.L.E. instuctions, and the logic is the same, but the DDJ
method of modifying a socket to piggy-back the current 74AS253 is better, I
believe (my opinion).  I also installed a slide switch over the "tosh" silk-
screening by the reset switch so I can switch back to 128K (good thing, the
September Softworks C doesn't work with 512K).  It's an SPST switch with
common to E3-2, 128K side to E3-1, and 512K side to the 47K ohm resistor to
F3-7.
A 74LS253 worked where a 74AS253 or 74F253 was recommended, by the way.
There is an error in the DDJ article, but you will notice it because it is
inconsistent with the illustrations -- p. 20, first bullet after (9), it says
"bend out all the pins except 2, 7, 14, and 16."  The "7" should be "8".
This single article saved me about 15 years' worth of DDJ subscription cost!
Of course, Apple is partly to blame, and I don't get MacDraw and MacProject.
If they are as buggy as MacWrite and MacPaint, I'm not sure I'd want them.
> - Where is the cheapest place to get 256K bit DRAMS?
Microprocessors Unlimited, 24000 S. Peoria Av., Beggs OK 74421 (Tulsa suburb)
(918) 267-4961  open 6 1/2 days a week
They gave me terrific service.  A sheet included with the shipment stated
they would soon add 3% to credit card orders, with an alternative of the
customer sending a check the same day the order is made, also providing a
credit card, and mu P infinity (don't have Greek letters or lazy 8 in ASCII)
would turn in the credit card charge with the 3% added if the check didn't
show up in 7 days.  They prefer telephone orders to mail, so they can discuss
alternate vendors if your preference is out of stock.
About a month ago 150 ns. 256K RAMs were $14.47, when I ordered two weeks ago,
they were back up to $14.99 (Fujitsu).  120 ns. and Hitachi were a little
higher.  I don't think they stock the 74AS253 necessary for the Rev. C board,
but you could ask.  Note the Rev. F board does not require any chip, and the
modification description is on p. 4 of the January DDJ.