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Sir Muhammad Basit . . . . .
Sir Chris . . . . .as per . . . " Use your Ohmmeter instead " . . . . . . .
Referring back to the sole forthcoming information provided in posts 1-4 and 6 it just is being perceived that no instrumentation is being had / available and the only reference been made is merely to there being 120 VAC voltage and 12 VDC being available for any testing.
Dave has also deleted the universal language . . . .a photo . . . of my first choice of instrumentation to use.
That unit uses an insulated probe end for electrosatically picking up AC presence. It uses CMOS sensitivity in its front end to engage an end of circuitry RED LED indicator.
Bringing its insulated tip up against an insulated wire carrying 120 volt AC will have the internal LED lighting up at about an 1/8 of an inch of its proximity to that wire.
That aspect has been my go to choice for . . . . RAPIDLY . . . .fnding an open bulb in a series string of
lamps.
My procedure:
One just initially unplugs the very end lamp and plugs in the units AC plug and then notices the first lamp nearest that plug and it's wire that goes to the plug. That wire gets probed to confirm the first LED flash. If probing the companion wire out of that socket gets a flash, you have found your first good lamp. You then follow that last probed wire to its next series connected lamp socket and hoping for good lamps in each following socket.
UNTIL that no flash on an exiting socket wire, THEN, you put in that prior saved end bulb and see if that bulb is being good by repeating the same test.You should then be able to fly down the string,excepting the time used for pulling an open / bad lamp. Where you just pull and insert another
"good" lamp from the end of the string.
At the end of the string you then see how many good lamps you will require.
This testing procedure goes much faster than pulling all lamps and individually testing each lamp.
AND THEN . . .there was the ALTERNATIVE procedure where a DVM was used as an electrostatic detector.
One takes the DVM's BLACK leads probe and grasps its metal probe end with spittle moistened thumb and fingers.
The other hand uses the RED leads probe placed against the insulated wire of the first lamp, just as was done above.
I expect a display number of the order of ~ 120 mv AC . . . .or more . . .if I'm standing barefoot on a concrete floor.
If you are having 230 VAC mains . . . up that reading even more.
NOW . . . .Muhammad
For its possibly simplest solution.
By your just following this pictorial operation at the very bottom of the page.
No meter needed
No ohms law to learn
No dropping resistor to understand
But with you possibly having the need of a friend's English translation skills if not quite understanding the Pictorial and mainly its explanation that now follows.
Contact your friend Jamal the tailor and get two of his smallest tailoring pins.
Contact your friend Sahib the Paki handyman and get two lengths of wire that are small enough gauge to permit coiling around those small pins ends and long enough to reach your 12VDC.
You say you already have the 12VDC. ( My shown 12VDC may be a bit more hefty than your 12VDC.. )
Look at the wiring near the power plug and you will observe that there is one wire that just travels from one end of the string of lights (
Wire B )
On 200 or 300 lamp strings expect 4 or 6 wires to be used.
And there is the most important wire (
Wire A ) which, if you trace it down, is going
into one lamp socket and then
out of that socket to the next lamp socket in the series of 100 sockets that are interconnecting 100 lamps .
The (
Wire B ) is just passing the whole distance of the wiring string and is of no concern to you, as it will not be involved in any connections.
Prepare a wire by tightly wrapping it around one sewing pin as is shown on the top left inset.
Locate the (
Wire A ) just to the left of the 4th lamp, and put it down on a non metallic solid surface and press the pin in the very center of the wire to pierce the stranded wire and then lift the wire to be able to further push the pin through the wire to make a good connection.
Wrap the end of that test wire around either one of the battery connections.
Prepare the other test wire with it tightly wrapping around the other pins end.
Take the other end of that same test wire and wrap it around the other battery connection.
Bring the pin up to the (
Wire A ) that is just to the RIGHT of the 1st lamp as is being shown in the right top inset and have that wire on a non metallic solid surface and make the pin go through that stranded wire in its center . . .then lift and pass the pin further through the wire .
If you are the luckiest man in Pakistan your four lamps will all light up, telling you that the 4 lamps are good and that your pins made good connection.
You can now pull that right pin out and see which of the end connections of the power plug will also make the lamps light. That then probably would be a better place to leave the right wire connected to.
If it didn't light, try changing in two different lamps into each of the four positions, hoping to find 4 good ones.
If it doesn't light on either terminal, sometimes there is a very small fuse built into that plug.. . . .which could be open and that was being your problem all along instead of an open lamp.
Once you have all lamps lighting, you can then just choose one lamp socket and unplug a good lamp and then rapidly plug in each of the other 96 lamps.
You only have to to press a lamp into the socket far enough to make initial contact to see if it lights.
That's it.
Thinking back now, if you are finding yourself having the availability of test wire, do you mean to tell me that you cannot ALSO come up with ONE flashlight battery and have an assistant hold the wire ends to the two ends of the battery.
And then YOU make connection with the opposite wire ends across the wires of a bare lamp and a good lamp will light up at half of its normal brightness . . . .BUT . . . . it is testing good . . .not bad..
Use this procedure for finding your initial 4 good GOOD lamps if required .
OR solely use this procedure for testing all of the lamps. Then there is a possibility of a fused power plug if all lamps don't light then.
P A N O R A M A :
73's de Edd
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