NorthStar HORIZON Manual page 48

F7. Insert and solder the crystal at location l5A. Bend the
leads so that the crystal will lie parallel with the PC
board. In addition to the two leads, the crystal should be
strapped to the PC board with a piece of clipped resistor
lead which is soldered to the pads on either side of the
crystal case.
F8. Install each of the two heat sinks and 5 volt regulators at
locations lC and lD as follows. Bend down the three leads
of the 5 volt regulator 90 degrees such that the leads go
into the correct holes while the machine screw holes line
up. Don"t solder yet. Fasten the heat sink and regulator
to the PC board so that the following sequence results from
bottom to top: 6-32 machine screw head, PC board, heat sink,
regulator, lock washer, and nut. Tighten the machine screw.
Now solder the regulator leads.
NOTE: Heat sink grease may be used though it is not
generally needed. Don"t tighten the machine screw too tight
or you will crack the PC board.
F9. Install the 12 volt 78L12 regulator (Q3) near location 28,
orienting the regulator so that the flat edge corresponds to
the flat edge indicated on the layout legend.
FlO. Install and solder the 34-pin cable connector header (J2).
The right angle bent pins should be inserted into the PC
board and the straight ends of the pins should be pointing
toward the top of the board.
Fll. Be sure the power is off and then plug the disk controller
board into a computer motherboard 100-pin connector. Be
sure the board is properly seated in the connector and then
turn on the power. Check for +5 volts ±5% (with reference
to the ground plane at the left of the board) at 3C pin 16
and at 2C pin 14. Check for +12 volts ±5% at location lA at
pin 7 of both the LF356 and the 3080. Turn off the power
and remove the disk controller from the motherboard. If the
voltage was not as indicated, locate and correct the problem
before going on.
North Star HORIZON Computer 48