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Gen7 Board-ARM 2.0 Assembly

This page is about how to solder a Gen7 Board-ARM v2.0. Everything lying around, in bags or single parts? Fine. Let's heat up the soldering iron.

General Notes on Assembly

  • Especially as a beginner, prefer leaded solder. Much easier to handle.
  • No expensive iron needed, but it should have a (simple) temperature regulation. Unregulated irons overheat, too much heat makes the solder flux vapouring away too quickly, leading to bad solder joints.
  • A solder sucker is cheap and well invested money.
  • To find out which components to put where, have the layout on your PC screen available.
  • PCBs fabricated with Voronoi paths need more heat, so raise your soldering iron's temperature by about 20 deg Celsius.
  • When soldering parts with many pins, like the ATmega socket, it's good practice to start with the four corner pins, recheck the fit, then soldering every other pin first, before completing the remaining ones. This keeps heat and strain to a minimum.
  • Start with the flattest parts, usually wire bridges or resistors. This way, components won't fall out when you lay the PCB on it's front for soldering. Then continue with parts of raising height.
  • The parts lists are sorted with that in mind, simply start at the top and assemble towards the bottom.
  • To ease soldering parts which fall out easily anyways, a small drop of glue onto the component side before inserting them helps.

Assembly in Detail

Caution: Don't solder MOSFETs or insert the LPC1114 until after the Voltage Measurements.

Click on the pictures to view them larger.

This is the layout, seen from the component side. If you're unsure, always refer to this picture of the layout. The designators match those in the [[Gen7 Board-ARM 2.0#Parts Lists|parts list]].

This is the layout, seen from the component side. If you're unsure, always refer to this picture of the layout. The designators match those in the parts list.

This is the layout, seen from the back. Note the MCP2200 on this side.

This is the layout, seen from the back. Note the MCP2200 on this side.

Start by marking the center line and the corner pins of the MCP2200. This is helpful for placing the chip.

Start by marking the center line and the corner pins of the MCP2200. This is helpful for placing the chip.

Such cranked pliers dub nicely as a weight for holding down the chip during soldering. Note the marking on the chip in the lower right corner, this has to be there and //not// top-left.

Such cranked pliers dub nicely as a weight for holding down the chip during soldering. Note the marking on the chip in the lower right corner, this has to be there and not top-left.

Soldering can be done even with a fat iron. If bridges appear, suck away excess solder, add more flux, and heat again.

Soldering can be done even with a fat iron. If bridges appear, suck away excess solder, add more flux, and heat again.

Start on the component side with the 9 wire bridges. They're the matte green tracks in the layout graphics.

Start on the component side with the 9 wire bridges. They're the matte green tracks in the layout graphics.

R11 and R12 have 10\_Ω, so they're color-coded **brown-black-black**.

R11 and R12 have 10 Ω, so they're color-coded brown-black-black.

R14, R19 and R22 have 560\_Ω, color code **green-blue-brown**.

R14, R19 and R22 have 560 Ω, color code green-blue-brown.

R2, R4, R6, R8, R10, R16 and RT1 (7 each) have 1\_kΩ, color code **brown-black-red**.

R2, R4, R6, R8, R10, R16 and RT1 (7 each) have 1 kΩ, color code brown-black-red.

The other thermistor comparison resistor, RT2, has 4.7\_kΩ, or **yellow-violet-red**.

The other thermistor comparison resistor, RT2, has 4.7 kΩ, or yellow-violet-red.

R1, R3 and R30 are 10\_kΩ, coded **brown-black-orange**.

R1, R3 and R30 are 10 kΩ, coded brown-black-orange.

The last 3 resistors, R1, R3 and R30 have 1\_MΩ, color code **brown-black-green**.

The last 3 resistors, R1, R3 and R30 have 1 MΩ, color code brown-black-green.

D1 and D2 are diodes, so you have to take care of polarity for the first time. Diodes have a white ring on the housing, which must end up closer to the bottom of the board.

D1 and D2 are diodes, so you have to take care of polarity for the first time. Diodes have a white ring on the housing, which must end up closer to the bottom of the board.

L1 looks like a thick resistor, but is actually a coil. Inserting direction doesn't matter here. Color code is **brown-black-black**.

L1 looks like a thick resistor, but is actually a coil. Inserting direction doesn't matter here. Color code is brown-black-black.

U6 is the crystal generating MCP2200's clock. Insert it in either direction.

U6 is the crystal generating MCP2200's clock. Insert it in either direction.

Now it's a good time to insert all the 10 noise canceling capacitors, C8...C17 and C19. Again, direction doesn't matter.

Now it's a good time to insert all the 10 noise canceling capacitors, C8…C17 and C19. Again, direction doesn't matter.

C3 and C4 make the clock crystal swing, insertion direction doesn't matter.

C3 and C4 make the clock crystal swing, insertion direction doesn't matter.

gen7_board-arm_2.0_assembly.1457014795.txt.gz · Last modified: 2018/05/27 16:10 (external edit)