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The Mute Audio pupDAC

pupDAC Step-by-Step
1. Solder PCM2706/7 chip anchor points -
Both corners are needed to keep the chip from rotating when soldering. Anchor points are on the top and bottom rows, allowing free soldering for the left and right side pins in Step 2 below. Alternatively, you could solder anchor points on the left and right rows, allowing free soldering for the top and bottom rows. Be sure you solder only one pin pad first, melt it, and while melted, place the chip on the pad with tweezers. If you put solder on both anchor pads initially, you will not be able to place the chip flatly and it will terribly hinder your soldering the rest of the chip to the PCB. Only apply solder the 2nd anchor pad and pin after you've placed the chip.

Warning! Make certain the the chip is oriented to match the locating dot on the PCB silkscreen.


2. Solder PCM2706/7 chip left and right side pins -
Both anchor points are needed to keep the chip from rotating when soldering. Anchor points are on the bottom and top rows, allowing free soldering for the left and right side pins in Step 3 below.

Refer to the SMD soldering page for details on soldering the pins.


3. Solder PCM2706/7 chip top and bottom row pins -
4. Solder PCM1794 DAC chip anchor points -
Both corners are needed to keep the chip from rotating when soldering. Be sure you solder only one pin pad first, melt it, and while melted, place the chip on the pad with tweezers. If you put solder on both anchor pads initially, you will not be able to place the chip flatly and it will terribly hinder your soldering the rest of the chip to the PCB. Only apply solder the 2nd anchor pad and pin after you've placed the chip.

Warning! Make certain the the chip is oriented to match the locating dot on the PCB silkscreen.


5. Solder DAC chip pins -
Refer to the SMD soldering page for details on soldering the pins.


At this point, it would be a good idea to thoroughly, thoroughly check for bridges on both chips. Once you continue on with the soldering of the rest of the PCB, it will become almost impossible to get proper access to the primary chips if something's wrong. How to do this?
  • Hold the PCB up to a strong light. The traces and separation from the ground plane should be clear. Bridges will show up, unless they're under the chips.
  • Use a DMM to check the continuity of the pins with the traces. Do this by applying one probe to a pin next to the body of the chip, not where it touches the trace. Follow the trace to another point or part on the board and place the other probe there. This will check for whether the chip's pin has a good connection to the trace.
  • Similarly, keeping one probe on the same pin, follow the trace from an adjacent pin to another point or part on the board and place the other probe there. Check for resistance of something greater than zero. This will check for whether the chip's pin may have a short (bridge) with the adjacent pin.
The above procedures are easier than they sound. Many of the pins are grounded, so those are repeatable and easy to check.
 
file last changed:Sunday, November 11, 2012 6:00:00 AM
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