| Multimeter. The multimeter needed to do these | | | | fuse simultaneously. If the deflection reading is |
| tests is an inexpensive ($10) handheld analog one | | | | zero for each fuse, they are okay. If not, replace |
| having a needle-deflection readout, and run by an | | | | the ones not having continuity; they can be found |
| AA-battery. Although multimeters can make | | | | in hardware stores. It might be easier to do this |
| several electronic measurements, the only two | | | | test by removing the fuses first, and then testing |
| needed here will be the 150-VAC (volts alternating | | | | each one outside the male plug. |
| current) and the resistance (ohms) ones. | | | | Step 3. Test the circuitry wires for continuity |
| Otherwise, a multimeter is kept in the off setting | | | | (unplugged). If the fuses are okay at this point, |
| to save the battery. | | | | insert one multimeter probe (still set to |
| For mini-lights, a multimeter can be used to test | | | | resistance) into one of the female plug sockets |
| the following issues. | | | | while the string is still unplugged. Touch the other |
| | | | probe to one of the male plug-in leads at the |
| 1. The circuitry voltage (120-VAC) while plugged | | | | other end of the string. If no reading occurs, |
| into an outlet. These two wires work | | | | touch the other male lead instead. One of these |
| independently from the bulb wire attached to | | | | two male leads should yield a zero reading for a |
| them in a three-wire string. | | | | good (continuous, unbroken) wire at this time. |
| 2. The continuity of the two 3-amp buss fuses in | | | | Perform the same test from the second |
| the male plug if the circuitry was not working | | | | female-plug socket. |
| when tested while plugged in. | | | | If both wires do not give a zero continuity |
| 3. The continuity of each circuitry wire (hot | | | | reading, something is wrong with the circuit wiring. |
| & cold) if the circuitry was not working when | | | | Visually check these wires for damage. Repair any |
| tested. | | | | damage, if found, and retest them. If the circuit |
| 4. The continuity of individual bulbs (i.e., for | | | | wires now show continuity, and the bulbs are still |
| non-working filaments and bypass shunts, and for | | | | out, move to the next step. |
| slightly corroded lead wires). | | | | Step 4. Test the individual bulbs for continuity |
| Safety. Since 120-volts of electricity pass through | | | | (unplugged). Because the bulbs in question must |
| most mini-light strings, basic safety and correct | | | | be removed for this test, this process is much |
| procedures are paramount in testing them. | | | | slower than by examining them with a magnifier |
| Persons who know nothing about electricity, nor | | | | and background light. Still, surprisingly, a few bulbs |
| how-to-use a multimeter, should at least read-up | | | | that look okay with the magnifier might not test |
| on these subjects. Better yet, get professional | | | | okay with the multimeter. |
| hands-on training on them. Otherwise, the string | | | | Thus, the multimeter's probes must make good |
| and multimeter could be damaged, not to mention | | | | contact with each of the bulb's lead wires for a |
| the tester him or herself. | | | | successful test. That kind of contact can be |
| Step 1. Test the circuitry. Plug the non-working | | | | assured by scratching the bulb's wire leads with a |
| string into a working outlet. Set the multimeter | | | | sharp-edged tool until shiny before testing them. |
| to150-VAC. Insert one multimeter probe into each | | | | Replace any bulbs testing bad (no continuity). |
| of two female-plug sockets. (Most mini-light plugs | | | | Conclusion. Experts indicate the lifetime of the |
| are two prong.) The readout should be about | | | | incandescent mini-light bulb is 3-to-5 years, |
| 120-VAC, which means the circuitry is okay. If no | | | | depending on its amount of usage. After |
| reading occurs, double check the probe contacts | | | | maintaining these light strings for that length of |
| in the female plug. If still no reading, unplug the | | | | time, it is time to get new strings. If the same |
| string, and do the next step. | | | | kind are purchased, the old ones can be used for |
| Step 2. Test the fuses for continuity (unplugged). | | | | spare parts and bulbs. Yet, the LED (light-emitting |
| Slide open the panel door on the male plug. Set | | | | diode) strings might be a good option to consider |
| the multimeter to a moderate resistance setting | | | | at this point. They last longer than the |
| (inexpensive multimeters will have only one | | | | incandescent ones, and they use up to 10-times |
| setting). Touch its probes together. The reading | | | | less electricity. |
| should go to zero, i.e., the needle will defect to | | | | To learn more about multimeters and how to use |
| zero. | | | | them, see the following sites. |
| Touch one multimeter probe to each end of one | | | | |