The testing of the final assembly will require a short test drive of the K-28, engine and tender, it's hard work but I'm willing to go that extra mile (Oh Yea!).
The photo above is here to talk about a basic, but important point to always check when working on or modifying rolling stock. It is important to check your work to ensure proper stance and/or weight distribution. If you load all the sound components to one side, or shift a stock weight to make way for a component installation or some other modification, you may also be effecting the stance and balance as well. So, it's very important to check stance and weight distribution of the final assembly.
Now its time to take the first test drive, and you don't need the engine yet. The tender itself is placed on a test track and the power is applied. With this initial power-on test, the state of the system's battery is determined. If the startup sound sequence kicks off strong without any choppiness to the sound, then the battery is adequately charged and the testing can proceed. If the battery is determined to be too weak to produce clear, normal sound, then it needs to be charged at this point.
The battery is charged by setting the tender down on the test track and applying between 7 and 13 volts. As a rule of thumb I use the half throttle mark when charging from a standard powered track. The voltage could be more but the internal circuitry of the sound system will cut the excessive voltage anyway; the voltage should not be less because the battery may not charge properly.
With the battery charged, the tender is rolled back-and-forth on the test track, and even over some track magnets. If everything is properly installed and sounding properly, then it is time to get the engine and take a test run.
The points to check are:
Does the loco make the proper startup sound sequences for the direction you have it moving? That is two toots for forward and three toots for backward.
Does the bell sound when running over a left-hand, installed track magnet? Does the whistle sound when over top a right-hand?
Does the rear light glow brighter or even at all when the loco is moving backward?
Is the tender's brake house light able to glow?
Are the chuffs steady and constant when running at a given speed?
If the answer is "No" to any of the above, then more a little troubleshooting and work is needed. But everything checked out, so I decided to take the loco for a short test drive…