Dual Tualatin Processors on
the AMI MegaDual Board
The Problem
Since the MegaDual board is made to use Slot 1 processors, you need a
Slot 1 to Socket 370 adpater to use any PPGA/FC-PGA/FC-PGA2 procesor.
These adapters are often called "Slotkets" or "Slockets". The only
Slotkets that will work on this board are the "Super Slocket III", and
the FTK-370SPC (sometimes just 370SPC). These are fairly old models,
designed originally for use originally with PPGA Celeron processors
(the earliest Socket 370 processor). The problem is that the PPGA
Celerons use a different pin for the Bus Request 1 (BR1) signal than
the newer Coppermine and Tualatin Pentium III processors. This is one
of the signals required for dual processor mode.
Using a Single Socket 370 Processor
To use a single Socket 370 processor on the MegaDual board, you can use
either a Super Slocket III or a 370SPC without any modification. The
Super Slocket III must be jumpered for the Front Side Bus speed of your
processor (FSB speed), with the other jumpers on pins 1-2. The 370SPC
must be jumpered with all jumpers on pins 1-2. If you are using a
Tualatin core processor (such as the Pentium III-S), you must plug a
Lin-Lin "Celeron III" Tualatin adapter into the Slotket, and then plug
the processor into the Lin-Lin adapter. The Lin-Lin must be jumpered
for the core voltage and FSB speed of your processor. And on the 370SPC
socket, you need to break off pin AN15 of the Lin-Lin (more on that
later). Here is a guide
for jumpering the Lin-Lin adapter:
Jumper Settings for the Lin-Lin Socket
370 Adapter
Voltage Configuration
|
|
No Jumpers a1
through b3
|
1.30V
|
a8-a9
|
1.35V
|
a2-a3
|
1.40V
|
a2-a3 a8-a9
|
1.45V
|
a5-a6
|
1.50V
|
a5-a6 a8-a9
|
1.55V
|
a2-a3 a5-a6
|
1.60V
|
a2-a3 a5-a6 a8-a9
|
1.65V
|
b2-b3
|
1.70V
|
a8-a9 b2-b3
|
1.75V
|
a2-a3 b2-b3
|
1.80V
|
a2-a3 a8-a9 b2-b3
|
1.85V
|
a4-a5 b2-b3
|
1.90V
|
a8-a9 b2-b3
|
1.95V
|
a2-a3 a5-a6 b2-b3
|
2.00V
|
a2-a3 a5-a6 a8-a9
b2-b3
|
2.05V
|
FSB Configuration
|
|
b5-b6 b8-b9
|
66MHz
|
b8-b9
|
100MHz
|
No Jumpers b4
through b9
|
133MHz
|
If you have a processor requiring 1.475 volts, jumper the Lin-Lin for
1.50 volts. This is within the tolerance range of the processor, and
will not harm it.
Dual Processor Modifications
To use two Socket 370 Pentium III processors in the MegaDual board, you
need a 370SPC for the first CPU slot, and a Super Slocket III for the
second CPU slot. Both of them must be modified so that the correct pin
for BR1 is used. The Lin-Lin adapters must be modified as well, to
remove pins that are not used.
Modifying the 370SPC
Note: Before beginning any modifications, test your Slotket in the
single processor mode. It wouldn't be good to work on a Slotket that
was no good in the first place.
Note: These modifications are for Tualatin core processors only.
Coppermine processors requre a pull-up resistor on the X2 pin that is
not required by Tualatin processors. If you want to use Coppermine
processors, you will need to add a 68 ohm resistor from pin X2 to one
of the VTT pins.
To modify the 370SPC, position it so that the back side is up, and
locate pin B75 (the Slot 1 BR1 signal) on the edge connector. Follow
the trace coming from it until it ends at a feed-through hole. Using
small guage wire-wrap wire, solder a jumper from this feed through hole
to pin X2 (the BR1 signal) on the Socket 370. Refer to the
illustrations below. Now, turn the board over and locate the
feed-through hole to which you soldered the jumper wire. Cut the trace
coming from the hole. This completes the modification.
370SPC with the jumper wire in place.
Detail of the jumper wire connecting Slot 1 pin B75 to Socket 370 pin
X2.
Detail of the top side of the 370SPC, showing the feed-though hole with
the jumper soldered on the other side of it. The trace should be cut
right next to this feed-through hole.
Modifying the Super Slocket III
The modification required on the Super Slocket III is identical to the
370SPC modification, except that the trace coming from pin B75 takes a
slightly different path, so the location of the feed-through hole where
you must connect the jumper wire is different. Here are the
illustrations
Super Slocket III with jumper wire in place
Detail of the jumper wire connecting Slot 1 pin B75 to Socket 370 pin
X2.
Detail of the top side of the Super Slocket III, showing the
feed-though hole with
the jumper soldered on the other side of it. The trace should be cut a
short distance from this feed-through hole.
Modifying the Lin-Lin adapters
On the Lin-Lin adapters, you must break off pins AN-15 and N33.
The easiest way to do this is to bend the pin over with the blade of a
jewelers screw driver and straighten it up again. Repeat this until it
breaks off. (Picture coming soon).
Cooling Your CPU's
You can use a standard heat sink and fan on the processor in the second
CPU slot, but for the CPU in the first slot, you will need a low
profile heat sink and fan. The best kind to use is a copper "1U" heat
sink with a side blower, as seen in the illustration below.
