General Building Tips - Sam -III Construction Manual

II. General Building Tips – READ THIS BEFORE STARTING:
 The SAM-III kit is built using conventional electronic construction techniques. All components are
through-hole types except the pushbuttons on the keyboard, which are SMT
 You will need a digital or analog multimeter to properly assemble and test this kit. it must be able to read
resistance up to 500k ohms and voltage up to about 20 Vdc.
 Before starting assembly, perform an inventory of all components – see the file SAM Kit Parts List.xls on
the CD
 Some parts are very small and easy to lose or may become tangled with other parts (for example,
connector contacts), so be careful emptying the reclosable plastic bags and keeping track of the parts
during inventory and during assembly
 As you inventory the parts put them back into their bags so they are not lost
 Resistors supplied with the kit may or may not have color coded stripes to indicate their value. The colors,
if used, may have little contrast and be difficult to read. Confirm all resistor values with an ohmmeter
 Use Sn63Pb37 or Sn60Pb40 solder with a diameter ≤ 0.031 in. (0.8 mm). For surface mount technology
(SMT) use 0.015 in. (0.4 mm). Lead-free solder is not recommended except by builders with considerable
experience using lead-free solder. Lead-fee solder requires more heat and greatly increases the possibility
of PCB and component damage, especially if any components have to be replaced after installation
 Soldering component leads to the grounded pads may require a 60 W or greater soldering iron; only use a
soldering iron with a very fine tip

Use a temperature-controlled soldering iron set to 315 to 350 °C; use the lowest temperature that works
best with the solder and soldering iron tip. Cheap hobby-shop soldering irons are not recommended
 Review online sources for soldering techniques if necessary
 The parts required for construction are listed in a table at the beginning of each section. As each
component or group of components is soldered and trimmed, place a checkmark in the boxes provided
 READ ALL NOTES AND COMMENTS that follow the parts list in each section before assembling or soldering
any components
 To avoid the porcupine effect, install only three or four resistors or capacitors at a time. After soldering
the small group of components, trim the extra lead lengths with a flush cutting wire cutter but leave a
small extension of each lead below the PCB (approximately 1/16" or 1 or 2 mm)
 After completing each section of the construction manual, use a magnifying glass and bright work light to
examine each and every solder joint for inadvertent bridges or cold solder joint. Do not proceed with the
next section until repairs are made
 The leads of some components are taped together. Do not pull the leads out of the tape and then insert
into the PCB. The tape gum may scrape off and make soldering difficult. There is plenty of extra lead so
simply clip the part of the lead contacting the tape
 Dual-inline (DIL) integrated circuits and their sockets will have a dimple or notch on one end and it must
be oriented as indicated on the PCB silkscreen
 Diodes have a bar or stripe on one end and it must be oriented with the bar indicated on the PCB
silkscreen
 Electrolytic capacitors are marked with a bar on one side, indicating the negative lead, and one of the
leads is longer, indicating the positive lead. The positive (longer) lead must be inserted in the hole with a +
symbol indicated on the PCB silkscreen
 Leave all integrated circuits and other semiconductor devices in their anti-static carriers (pad and
aluminum foil) until they are to be installed
 Use anti-static protection whenever installing or handling integrated circuits and other semiconductor
devices
 After integrated circuits and other semiconductor devices are installed on the PCB, use static protection
whenever handling the PCB
See last page for document and copyright information, File: SAM-III Magnetometer Construction.doc, Page 3
SAM-III Construction Manual