English: 2.2 Inital startup - WLANThermo/WLANThermo_Hardware GitHub Wiki

Prerequisits

  • mounted and soldered PCB as described
  • ICs not set
  • Raspberry not connected
  • Sensors not connected
  • 5V Micro-USB Powersupply ready, not connected
  • PCB is lying on a non conducting, clean surface

Measuring

  • A functional Multimeter must be available (ideal digital type)
  • Voltage range up for 5V. Usually it's the 20V range then.
  • Measuring always agains GND. GND can be found at the rings around screwholes. Connext black cable of multimeter with GND.
  • Measuring is done from the top of the PCB with the red cable. Multimeter in Voltage-mode.

Where are the measuring points on the PCB

measuringpoints mini PCB

Startup

I know it's boring to check everything again but its better than ending up with a fried Raspberry (might taste nice but...) or a non working PCB. Especially when you are not trained in soldering PCBs. This description is adressing electronics-rookies with litlle or no experience and those seeking help in the forum. If you go thru the checklists and check every item, you can be sure that you have checked everything that's relevant.

Optical inspections of the soldering

  • Check every solderingspot on the lower side of the PCB for good soldering. Use magnifying glass and/or at least ensure good lighting-conditions!
  • If in doubt, resolder!
  • remove short circuits (solder-beads)
  • remove soldering residues with alcohol.

check of polarity-relevant components

  1. IC-socket "MAX604CPA": notch up
  2. IC-socket "MCP3208-CI/P": notch left
  3. IC-socket "TLC72ACP": notch up
  4. Diode D1: ring up
  5. Diode D2: ring up
  6. capacitor C16: - marking right
  7. capacitor C14: - marking left
  8. capacitor C1: - marking down
  9. capacitor C13: - marking left
  10. Tantalcapacitor C12: + marking left
  11. Tantalcapacitor C11: + marking down
  12. Transistor BC337-25: flat side left
  13. Transistor BD131-16: cooling surface down
  14. Beeper: cutoff corner up right

DC Power

  1. connect 5V to "+5V In"
  2. Check point A - expected result: 4.8 - 5.5V
  3. disconnect 5V

Referencevoltage Analog

  1. put in IC "MAX604CPA" notch up
  2. connect 5V to "+5V In"
  3. Check point A - expected result: 4.8 - 5.5V
  4. Check point B - expected result: 3.15 - 3.45V
  5. Check point C1 - expected result: 3.15 - 3.45V (more exactly like point B)
  6. Check point C2 - expected result: 3.15 - 3.45V (more exactly like point B)
  7. Check point C3 - expected result: 3.15 - 3.45V (more exactly like point B)
  8. Check point C4 - expected result: 3.15 - 3.45V (more exactly like point B)
  9. Check point C5 - expected result: 3.15 - 3.45V (more exactly like point B)
  10. Check point C6 - expected result: 3.15 - 3.45V (more exactly like point B)
  11. Check point C7 - expected result: 3.15 - 3.45V (more exactly like point B)
  12. Check point C8 - expected result: 3.15 - 3.45V (more exactly like point B)
  13. disconnect 5V

Outputvoltage Step-Up

  1. solder in IC LM2577-ADJ
  2. check solderpoints
  3. check distance of the pins on the upper side of PCB - no short circuits!
  4. connect 5V to "+5V In"
  5. Check point A - expected result: 4.8 - 5.5V
  6. Check point D - expected result: 11.5V - 12.5V
  7. disconnect 5V
  8. Mount IC TLC272ACP
  9. connect 5V to "+5V In"
  10. Check point A - expected result: 4.8 - 5.5V
  11. Check point D - expected result: 11.5V - 12.5V
  12. disconnect 5V

mount remaining parts

  1. mount MCP3208-CI/P
  2. mount Raspberry Pi Zero with configured SD-card
  3. connect monitor to HDMI-Port
  4. connect keyboard to USB-Port
  5. connect 5V to "+5V In"
  6. Expected result: see RasPi booting on screen

Continue with softwareinstallation according to description.