TROUBLESHOOTING INSTRUCTIONS
Since this circuit contains relatively few components, problems are usually due to mental errors rather than component failures. The most common errors are in assembly, especially with the IC chips. Check for solder bridges or splashes. Check your parts placement, “Hmmm... is that resistor in the correct holes?” Have the electrolytic capacitors been installed the right way? Check also for “cold” (dull or “bumpy” looking ) solder connections.
If you have looked it all over and cannot find the problem, another idea is to have a friend check it as well. We’ve all looked at a board with an obvious problem but seemed to have a “mental block” when we looked at our error over and over.
If you own some test equipment (such as a VOM or oscilloscope) use some good, logical trouble-shooting methods. Verify that the voltage regulator is working correctly and that power is supplied to all the power “busses” shown on the schematic. A scope can be used to trace the audio signals through the forward and reverse paths of the circuit. Loop the audio through the SS- 70A, having it scramble and unscramble, compare to see where a problem lies.
It’s maddening to us all to have a kit not work initially. Please understand that, unfortunately, it is nearly impossible to troubleshoot over the phone, and the best solution is to work the step-by-step assembly instructions backwards to verify parts placement. This method usually solves the problem.
WHAT IF I CAN’T DESCRAMBLE SOMETHING I HEAR?
Although the SS-70A utilizes the most common form of scrambling, it won’t be able to decode all styles of scrambling. Let’s look at it realistically, do you really think an expensive, truly secure communications link would be so easily decoded - by a $50 kit no less? Communications is scrambled for a reason, and that’s to keep other folks from listening in! In many cases, simple speech inversion (as used in the SS-70A) provides enough security to keep things private. When National security is at risk, only the most complex and expensive schemes will do. Your local police department may fall somewhere in between.