I have done the following. Prepared the necessary tools and fixtures:
1. a small wooden plaque approximate size 300х100х 10 mm (length x width x thickness);
2. two needles;
3. battery power supply to 4.5 volts (“five”);
4. the conductors from the tester with clips;
6. soldering iron.
Then laid the garland on the table, turned it on 220 volts and determined by color, which bulbs and what wire do not burn. Have turned off the lights and put it under the Board (see Fig.2).
Needles, with pliers, pierced the insulation before the bulb and after it. The same needle was keeping the wire pinned to a wooden Board. Connected the power supply and found the bulb that does not Shine. If you remove the power source and shorting two points (e.g. A and B or B and b, or a and D), the chain garland is connected. Now, following the rules
safety with electric included garland in the network of 220 volts. If more open or a faulty bulb was not the garland worked in all modes and shone with all the colors available. If somewhere there was a malfunction, garland has not worked, not worked the circuit, such as green lights, and all the rest worked. In this case, there is nothing like a gradual test with needles the whole chain: determining the fault – it needs to be eliminated and move on.
Fig. 1. Circuit diagram of Christmas tree lights (L1 L100.. – bulbs)
Fig. 2. The scheme of check of serviceability of lights Christmas garlands:
1 – wire insulation; 2 – light; 3 – needle (2-4 units); 4 – battery power supply (“five”), U=4.5; 5 – backing plate (300x100x10)
Fig. 3. Remove a light bulb from the circuit:
1 – insulated conductor; 2 – large poly-vinyl chloride pipe; 3 – little polyflor-vinyl tube (2); 4 – light
If, for example, a 12 volts power supply, you can check three lamps (3×4 = 12), and where they are not burned, to find out one of them is faulty in the way described above.
The plastic insulation of the conductors, punctures in it are progressing nicely, and garland will be safe. If there is nothing to replace the bulb, just the bulb desoldering, the short-circuiting conductor and insulate the place as shown in figure 3. Work garland as a whole is not affected.
Thus it is possible to repair and save a garland, and renovated, it will serve you long and reliable, because you replaced defective light bulbs and fixed a poorly actuated contacts.
V. GERUS, Zdolbuniv, Ukraine