Synthrotek will always try its best to provide builders with accurate and useful building instructions, however problems and errors are unavoidable due to various reasons. This page is dedicated to helping builders figure out what could be wrong with their circuit or build, and how to hopefully fix it.
Here is a list of the most common issues that we see and please go through this list one-by-one if you are having any problems. Please do this before sending a support email if possible, most likely we will give you the same information. If you find that you are stuck, you can take a look at the ‘returns’ section on our support page for our repair policy. PLEASE DO NOT JUST FOLLOW THE KIT ASSEMBLY PHOTOS ONLY, USE THE BILL OF MATERIALS AND INSPECT YOUR COMPONENTS CAREFULLY BEFORE YOU BEGIN ANY SOLDERING.
Tools you may need:
- Soldering iron and solder
- Solder sucker or solder wick
1. Component Placement Errors
a. Incorrectly Placed Polarized Components (Diodes and LEDs & Electrolytic Capacitors). Components such as diodes and electrolytic capacitors are polarized, which means that they have ‘positive’ and ‘negative’ leads.
The Electrolytic Capacitors found in your kit are all radial and have to leads protruding from one of the ends. These two leads are polarized. One (Longer) Anode is POSITIVE and the (shorter) cathode is NEGATIVE (there is usually a large negative band on the body of the cap to let you know which lead is negative). There is a graphic designator for each capacitor on your PCB, please make sure to insert the Longer POSITIVE lead into the hole that has the “+” designator by it. LEDs are very similar, but you have the additional help of a flat notch on one side which corresponds to the PCB graphic.
Placing these components in a backwards or reversed position can possibly damage the component, damage the other components, and/or may make your circuit function improperly. Diodes particularly will often appear cracked or burned. If you find that have placed a component in backwards, please try to remove it carefully (search for “How to Remove Through-Hole Components from a Circuit Board” on the web) and place it back in properly. You may need a solder-sucker, or braided solder wick, which can be purchased at Radio Shack.
b. Incorrectly Placed ICs, Resistors, Non-Polarized Capacitors, and Transistors
Most ICs or Integrated Circuits are black with multiple legs and have to be properly aligned. The keyed notch on the top side of the IC has to correspond with the graphic notch on the PCB itself. Some ICs have no notch, but do have a circular indicator next to pin #1, which will always be just to the left of the notch, which means that the side of the IC that has the circle is the side that the notch would be on.
Check to make sure that all the IC legs are fully inserted. Sometimes one leg will bend and not insert into the socket properly.
Make sure your ICs are fully seated. You have to push on them a little in order for them to fully seat in their sockets.
Resistors are non-polarized components and can be placed in either direction into the PCB. Some of the resistors we supply may have a beige color (representing 5% tolerance) and some may be blue (representing 1% tolerance). The beige resistors have 4 bands and the blue have 5. Please take a look at the Visual Bill of Materials that came with your kit to find the value of each resistor BEFORE soldering it to the PCB. You can also use our RESISTOR CODE CHART. Don’t refer to our assembly instruction photos for resistor values, use the Visual BOM instead.
Non-Polarized Capacitors are like non-polarized resistors in that it does not matter which way you orient the leads. The graphic on the PCB should NOT have a “+” marking next to these capacitors and is an extra hint not to use electrolytic caps here.
Also note that some ceramic capacitors have a coating that runs down the leg of the capacitor. Make sure when soldering that cap that the coating doesn’t go through the via. You may not get a very good connection if it does.
The transistors in our kits have 3 legs and have to be inserted correctly as well. The 3 legs are the Base, Emitter and Collector. Just pay attention to the key designator on the graphic of the PCB when inserting. Most transistors that we include in our kits have a flat edge, which corresponds to the flat edge on the PCB graphic. Our AC-128 germanium transistors have an extruded metal notch, align this as well with the graphic on the PCB.
NOTE! Voltage regulators can often look like a transistor, this component is not interchangeable, please put them in their respective locations.
2. Soldering Errors – One of the most common build that we run into from customers are a few different soldering errors. Although we are all about cheap and DIY projects, it might be a good idea to invest in a good soldering iron. Most low wattage non-temperature-controlled irons take a long time to heat up to a useable temperature and can damage your PCB. It is actually better to move faster and hotter than slower and colder. This is because the temperature on even a colder soldering iron can damage the vias (holes where you put your components), traces, or components even if your solder is not melting very fast. You want to keep the tip of your iron on your PCB as little as possible. You also do not have to apply pressure to the board when soldering. Excessive pressure can damage vias, traces and soldering iron tips. Old worn out tips can also also cause damage to your traces, because worn out tips often have rough edges can cut your board. Also very large tips and very small tips should be avoided when soldering through-hole projects. We like to use ETP and ETK tips from Weller.
a. Cold Solder Joints are a result of not adequately and evenly heating both the via AND the component lead prior to applying solder. Make sure you touch your iron tip to BOTH the component and via at the same time. Sometimes this is hard to do if you have a large tip, so please find a size where you can heat both easily. A good solder joint should look like a Hershey’s kiss. Here is a photo of some various joints that have been soldered incorrectly. Cold solder joints may not make a good connection in the circuit and can lead to circuit failure. If you would like to learn more about soldering properly, please search the web, as there are so many more and better videos and tutorials then we could ever make here.
b. Damaged Traces or Vias (Accidentally Cut Traces or Vias, Burned Out Traces or Vias, Lifted Vias). Traces and Vias are made up of very thin copper on your PCB. These can be damaged by excessive heat, pressure, cutting, component removal, and when clipping component legs. Since a damaged via or trace can be hard to see at times, it is essential that you use a multi-meter when debugging your project. Check to see if the circuit is making a connection from one point to another. If you are using the ‘continuity’ setting on your meter you may get a ‘beep’ when there is continuity between the points or you may use a ‘diode’ setting that shows you voltage passing. Please also do a web search if you need more information on continuity testing. If a trace is found to be damaged, then you will have to use a small piece of jump wire to connect the points, as they will no longer be connected on the PCB.
Trace 1 (the pink trace) connects two vias directly on the underside of this board. You can check for continuity between these pretty quickly with a multimeter.
Trace 2 (the yellow trace, starting on the left side of the picture) starts on the bottom side of the board, but then goes to the top side of the board through a tiny via. On the top side of the board, a small trace (not pictured here) runs horizontally over to another tiny via, which connects to the bottom side of the board again. The tiny via on the bottom side of the board then finally connects to a solder point (the yellow trace on the right side of the picture).
If you draw an imaginary line between the two tiny vias in trace 2 on the bottom side of the board, that line will be perpendicular to the traces. Once you have checked traces a few times, you might not have to flip the board back and forth much. You will be able to intuit where they connect on the bottom of the board.
c. Solder Bridges. Excessive amounts of solder can connect 2 or more places on your PCB that should not be connected. Be careful not to use so much solder that you cause a bridge. You may need to use a solder sucker or wick to remove this excess solder.
3. Damaged Components
a. Burned Out Components (Too Much Heat From The Soldering Iron). This issue is more rare, but can happen by applying to much heat for too long of a time. Some components, such as polystyrene capacitors, are sensitive to heat and will burn out very quickly.
b. Destroyed Components (Excessive Voltage, Reversed Polarity, Using The AC Adaptor For DC Circuits and Vice Versa). Components can be damaged when they are fed too much voltage, placed incorrectly or backwards or by using the improper amount or polarity of power input. Please be sure to check the polarity on your DC voltage source. The Power Brick that you may use to power your product has a polarity marking which is either Center Positive OR Center Negative. THIS POLARITY IS IMPORTANT, please make sure that you never plug in the wrong polarity. Also, none of our products take AC power directly.
4. Wiring – Many of our kits require wiring. The biggest issues here are correct wiring so that your wires are connecting the wires to the proper holes on the PCB. Also, when stripping wire to insert into the PCB, please strip the wire then ‘tin’ the wires by twisting the strands together then applying a small amount solder to the twisted ends. This will also help eliminate any frayed wires that may spread out onto the circuit board which may connect parts of the circuit that should not be.
Nine times out of ten, following the steps here will fix the problem. If that doesn’t solve it, email us at firstname.lastname@example.org for help.
Thanks for DIYing with Synthrotek!