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Troubleshooting - Eggtimer Rocketry Rev A4a Assembly And User's Manual

Wifi switch

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Troubleshooting

If your Eggtimer WiFi Switch doesn't work after assembly and testing, take a deep breath, get
out a beverage to clear you mind, and start troubleshooting...
Check Your Solder Joints
The very first thing you should do is to check out all of the solder joints under a lighted
magnifier, or with a 10x jeweler's loupe or magnifier. The most common reason for things not
working are solder bridges, i.e. putting too much solder on the pads and shorting two adjacent
pads together. You can also get into problems by bridging pads with "vias" on the board, the
smaller holes that don't have any components soldered to them. Most of the holes and the pads
are very small, so it doesn't take much solder to get a nice "tented" solder joint. If you get a
solder bridge, heat it up and use a solder wick or a vacuum bulb to remove the excess;
afterwards, we recommend resoldering the joints. Note: NEVER use "canned air" or
compressed air to "blow away" excess solder. The resulting solder splatter will almost always
cause more damage than the original solder bridge.
Another thing to look out for is "cold" solder joints, they look dull and blobby compared to a
nice shiny "tented" solder joint. Cold solder joints won't conduct well; at the low power that
the WiFi Switch uses this could easily keep things from working. If you have a cold solder
joint, heat it up and put just a little bit of solder on it, the main idea is to get a little more flux
on the joint. If there's too much solder, use a fine solder wick or (preferably) a vacuum bulb to
remove the excess, then heat it up and resolder the joint.
Check Your Component Polarity
Most of the small components aren't polarized, with some notable exceptions. The outline of
the parts is silk-screened on the board, so you should be able to see readily if you have a
component soldered in backwards. Some of the components are not symmetrical (i.e. the
voltage regulators) so they would be difficult to install backwards, too.
In particular, you need to check the LEDs, the side with the long lead should be inserted into
the holes marked "+". Unfortunately, once you've soldered them in and clipped the leads it
will be difficult to tell, so make sure you get it right the first time.
If you inserted a component incorrectly, you will have to carefully unsolder it, clear any solder
residue from the holes, and resolder it. If you find that a component was soldered incorrectly,
you will have to use a vacuum bulb or vacuum desoldering tool to unsolder it. We cannot
stress enough that you need to check the orientation of the parts before you solder them. The
Eggtimer WiFi Switch Limited Warranty does not cover damage to a component while
attempting to unsolder it, so make take your time and make sure you get it right before you
solder.

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