🚀 go-pugleaf

Someone asked for the key items of DDJ's article on upgrading
your own mac to 512k, so here they are--or at least some
of them.  If you actually plan to do the upgrade, I suggest
very strongly that you actually get a copy of the article
for warnings, pictures, etc.

Apparently there are two common board revisions, and there are
different instructions for the two different boards.  I'll give the
instructions for the newer board; the older one is similar but a 
little more complicated.

Parts needed:
	- a low-temperature (700 degree) soldering iron
	  Weller WTCPN recommended for its magnetised tip
	- solder sucker
	- Xcelite XTD-10 Torx screwdriver, 6" shaft

	- 2, 2.2k 1/4w resistors
	- 1, 47-ohm 1/4w resistor
	- 1, .1uf cap
	- 1, SN74AS253N ic (or 74F253N)
	- 16 41256-200 200ns memory chips (NEC tested, but others
	  should work)
	- 17 16-pin ic sockets

Instructions:
	- take apart mac; remove motherboard
	- remove memory chips by cutting them off as close to the body
	  of the chip as possible
	  Remove the pins by desoldering them and pulling them out
	  with the magnetic soldering iron
	- Clean the holes of solder with a solder sucker
	- install ic sockets
	- install memory chips
	- test the mac (at this point it should still function as
	  a 128k mac)
	- cut jumper w1 (marked 128k only)
	- install 2, 2.2k resistors at r40 & r41
	- install 47-ohm resistor at r42
	- install .1uf cap at c51
	- install 74AS253N in the socket in g13
	- look for solder splashes, broken etch, etc
	- clean board with alcolol
	- test your 512k mac.

It's as easy as that!  The article, of course, gives more detailed
instructions, pictures, and so on.

Bear in mind, if you consider doing this, as I am, that If YOU break
you mac doing it, I don't want to be responsible, so I can't recommend
that you do it yourself.

By the way, anyone know where to get a Torx T-10 screwdriver with a 6"
shaft?  How 'bout a 74AS253N?  would 74LS...... work equally well?

				Harry Plantinga
				{seismo,inhp4}!uwvax!planting
				planting@wisc-rsch.arpa