This is an ascii file created on a word processor, which used
a width larger than 80 columns.

The outside dimensions of the board are 11.275 x 12.500 inches. There is a fiducial
200 mils above and to the right of the lower left corner, and layer 1 has the board
outline on it.

The board is 5 mil traces on 5 mil spacing, with a signal impedance of 65 ohms.

Each of the 10 signal and plane layers is labeled with a string "layer   n"
in the upper right hand side of the board, along with a copyright
notice. The numbers are written so that they fall in a sequence, however
the actual board is going to use a different stack up than the one suggested
by these labels.

Layer Label strings     name		function	direction	files
Layer 1					SIG1		Top Sig		Hor			art01.pho/rep
Layer  2				GND									pgp02.pho/rep
Layer   3				SIG3		Signal 3	Vert		art03.pho/rep
Layer    4				2V									pgp04.pho/rep
Layer     5				3V									pgp05.pho/rep
Layer      6			SIG6		Signal 6	Hor			art06.pho/rep
Layer       7			5V									pgp07.pho/rep
Layer        8			SIG8		Signal 8	Vert		art08.pho/rep
Layer         9			SIG9		Signal 9	Hor			art09.pho/rep
Layer          10		SIG10		Bot Sig		Vert		art10.pho/rep

The solder mask layers have been labeled 21 and 28 in the upper right corner.

						files
Layer  21	SMTOP		sm21.pho/rep
Layer  28	SMBOT		sm28.pho/rep

The original DEC board had 8 layers, this design has two new signal layers.
Since many of the highest speed signals are confined to the signal layers
labeled SIG3 and SIG6, we will get the best quality signals on these layers
when they are closest to the ground plane, which we have placed between
them. To reduce EMI emissions, we have placed the 5V layer between SIG3
and SIG1, which doesn't provide very much shielding. We have also moved
the plane layer labeled 3V into the number 9 position, again to improve
EMI shielding.

Actual stack up is



Stack up Order	Layer "Labels"  type		function	direction
1					Layer 1		TOP			SIG1		Hor
2					Layer 7		Plane		5V
3					Layer 3		Sig			SIG3		Vert
4					Layer 2		Plane		GND
5					Layer 6		Sig			SIG6		Hor
6					Layer 8		Sig			SIG8		Vert
7					Layer 4		Plane		2V
8					Layer 9		Sig			SIG9		Hor
9					Layer 5		Plane		3V
10					Layer 10	BOT			SIG10		Vert




We want to stay with the same thermals used by DEC. There appear to be 10
D codes devoted to thermals in our design. DEC uses a total of 5 horizontal
lines to replace these 10 D codes. We examined the orignal DEC board and 
found the relationship between round thermals and the horizontals used by DEC.
One of the five thermal types is a "null thermal," which is to say, nothing at
all. To switch, all we need to do is replace D105, D107, D108, D109, and D111
with a single D Code that uses a rectangle that is 70x12 mils, D codes D110 and D113
with a single D code that is 150x16 mils,  D112 with a D Code that is 45x6 and D114 
with a D code that is 35x7. I am not sure how to represent a null thermal, but one 
could always chose a round that is 1 mil in diameter. 



Use			D-Code	  Therm Dim		DEC Thermal
JMP/PCI/ISA	D105		60/45		70/12
Via1		D106		5/3.8		0/0 (null thermal)
DIMM Sock	D107		53/40		70/12
Electrolyt	D108		62/46		70/12
SROM Sock	D109		58/43		70/12
KB/Mouse	D110		120/90		150/16
Via2		D111		55/41		70/12
U40			D112		43/32		45/8
Power Conn	D113		100/75		150/16
StandVia	D114		35/26		35/7


Drill Information

We emited a pair of NC excellon drill files, and a single drill drawing.
These files all start with drl01.*, drl02.* and dd0124.*.

Mechanical Drawing,

We combined the top layer, a board outline and part outlines to create a 
mechanical drawing. The outer dimensions of the board are given, along with
the coordindates of 4 non-plated through holes which get used to mount the
board (and presumably could be used for tooling) and 4 surface fiducials. The
coordinates of these points were computed relative to the lower left corner.  



Silkscreens

The silkscreens were generated Using Orcad and use the RS274X format
These files are each labeled new75.sst and new75.ssb. The aperture list
is a part of the file, and the report on the aperature list that was
used follows. Note that we relabeled these files, from nmb_71aa_pd to
max75, which was the lablel we used for our main PADS .pcb file.


Post Processor Report
OrCAD FILE: C:\LX_REF\NMB_71AA_PD.MAX
Fri May 22 16:30:44 1998

*********************************************************

Output file: C:\LX_REF\NMB_71AA_PD.SST

Aperture totals for NMB_71AA_PD.SST:
---------------------------------------------------------
D40:  0.4200 SQUARE --       0 Draws,       4 Flashes
D41:  0.1500 x 0.0600 RECTANGLE -----       6 Flashes
D42:  0.0600 x 0.1500 RECTANGLE -----       2 Flashes
D52:  0.0120 ROUND  --     140 Draws,       0 Flashes
D81:  0.0080 ROUND  --    2457 Draws,       0 Flashes
D82:  0.0100 ROUND  --    1252 Draws,       0 Flashes
D83:  0.0010 ROUND  --     112 Draws,       0 Flashes
D84:  0.0060 ROUND  --   21225 Draws,       0 Flashes
D85:  0.0030 ROUND  --     864 Draws,       0 Flashes
D86:  0.0040 ROUND  --     359 Draws,       0 Flashes
---------------------------------------------------------
 10 D-Codes      -----   26409 Draws,      12 Flashes

*********************************************************

Output file: C:\LX_REF\NMB_71AA_PD.SSB

Aperture totals for NMB_71AA_PD.SSB:
---------------------------------------------------------
D81:  0.0080 ROUND  --     271 Draws,       0 Flashes
D82:  0.0100 ROUND  --     214 Draws,       0 Flashes
D83:  0.0010 ROUND  --      13 Draws,       0 Flashes
D84:  0.0060 ROUND  --    9212 Draws,       0 Flashes
D85:  0.0030 ROUND  --     566 Draws,       0 Flashes
D86:  0.0040 ROUND  --     276 Draws,       0 Flashes
---------------------------------------------------------
  6 D-Codes      -----   10552 Draws,       0 Flashes


*********************************************************

Aperture totals for entire project:
---------------------------------------------------------
D40:  0.4200 SQUARE --       0 Draws,       4 Flashes
D41:  0.1500 x 0.0600 RECTANGLE -----       6 Flashes
D42:  0.0600 x 0.1500 RECTANGLE -----       2 Flashes
D52:  0.0120 ROUND  --     140 Draws,       0 Flashes
D81:  0.0080 ROUND  --    2728 Draws,       0 Flashes
D82:  0.0100 ROUND  --    1466 Draws,       0 Flashes
D83:  0.0010 ROUND  --     125 Draws,       0 Flashes
D84:  0.0060 ROUND  --   30437 Draws,       0 Flashes
D85:  0.0030 ROUND  --    1430 Draws,       0 Flashes
D86:  0.0040 ROUND  --     635 Draws,       0 Flashes
---------------------------------------------------------
 10 D-Codes      -----   36961 Draws,      12 Flashes


No warnings or errors.
