Caple C871i Manual do Utilizador descarregar pdf (Página 302)

100

101

Apple II Computer Info

connecting to the right places. Have a picture or drawing showing the

pin-out for a Slot and have it oriented so that the pin#26/pin#25 end

matches positioning of the MB. Then, since you are working on the bottom

side, remember that left-right is switched.

So: with the MB back facing you, the Slots will be closest to you. Flip

the board over left-right to view the bottom.. On each Slot, The Slot pins

closest to you will be #26 (left) and #25 (right). #26 (left) is GND; #25

(right) is +5V. The PS connector is just to the left of Slot 1.

Bottom View

________________Front__End________________

| SLOT 1

| +12 (50) O O (1)

| PS Connector

| O GND

| O +5

| O +12

| O -12

| O -5 GND (26) O O (25) +5

|___________Back End ____(viewed from bottom)___

Use an Ohm meter to verify the above. Check resistance between PS

Connector GND and Pin 26 at each Slot. The resistance should be close to

zero in each case. (The meter may show close to 1 Ohm.) Mark GND for

Slots 1, 3, and 7 using whiteout or a marker.

Check resistance between PS Connector +5 and Pin 25 on each Slot.

Check resistance between PS Connector +12 and Pin 50 on each Slot. As

above, resistances should be very low.

NOTE: An Ohm meter passes a small current through the circuit being

measured. If you want to check R from, say, Slot Pin 1 to PS Connector +12

(to verify that Pin 1 is _not_ the +12 pin), then set the meter for X100.

This reduces the measurement current. By the way, there will be _some_

detectable connection between most circuit points and any of the PS

Connector points. The measured resistances will usually be fairly high.

Depending upon meter lead polarity, the measured resistance from a +5

point to GND may be fairly low; but, it will be significantly different

from zero. In general, avoid doing R measurements on the motherboard

except where you are verifying a likely direct connection.

Check out the empty case. You will get some idea of where supports

crop up to hold the motherboard. When connecting wires from the PS

connector to Slots 3 and 7, remember to leave enough slack to route around

the supports.

Apple II Computer Technical Information : Apple II Family Hardware Info

ftp://ground.ecn.uiowa.edu/2/apple2/miscinfo/hardware : May 2001 : 302 of 572

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Caple C871i Manual do Utilizador Página 302

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