Losing my mind! MR16 Pot

[Petvan]

Hi,

Curious if anyone has any ideas on this one. I have a string of 5 MR16's and 4 of them light, the 5th however will not. I've tried a number of bulbs with it to no avail. Note, it did light some time ago but has simples stopped working. However, there is 12V's on the bulb connector - voltage reading is the same for the lights which work. Also tried removing the other lights to see if it was a load issue, but no change.

I'm confounded by this and short of going into the attic and replacing the transformer or re-wiring I'm not sure what to do. Usually, when there is voltage there is light ;-)

P

 

[Shiftless]

I can’t think of anything other than a bad socket that will not properly contact the little pins on that MR16 bulb. I assume you’re 100% positive that the bulbs you try in that particular fixture are “good”.

If the other lights function properly, I’d say that it can’t be the transformer.

 

[Petvan]

Thanks Shiftless.. I am really at a loss. Power is there which suggests everything is fine, but no bulb will light and I've tried several, all of which light if I move a socket down the chain.

P

 

[Will S.]

Is it the bulb? Reverse the positions of the 1st one and 5th one. Is the 5th position still inop?

 

[tfi racing]

Time to trash those fossils, replace them with LED discs and be done with the nonsense of MR16 lamps.

 

[The Cobbler]

are the metal sockets making contact with the pins on the bulbs? that seems to be about all it can be , or broken wire that just happens to contact when you're testing it

 

[AntonLargiader]

Sounds like you have 12V with no load that goes to zero when you load it. Broken wire or something like that.

TFI, there are very modern LED lamps out there in MR16 format.

 

[cybrdyke]

Call a priest.
Here's how I would test it.
One known good halogen (not LED) lamp in mystery socket. No lamps in the others. If no light, then add 1 or 2 lamps to other sockets. If the others light and mystery socket doesn't then you have a bad socket or bad wiring to mystery socket. Replacements on Amazon are cheap.

Other considerations...are there controls on this circuit, like a dimmer? Could it be over capacity or past it's useful life?
CD

 

[gpiggaz]

You likely have a high resistance connection either at the socket or transformer- The reason the Volt meter reads 12V is because it's a high impedance device the bulb on the other hand is a low impedance device and therefore it has all the voltage dropped across the high impedance connection ( either at /in the socket or the connection to the transformer. Sounds like you need to take it down and either replace it or fix the broken wiring.

 

[Chuckster in NJ]

Replace the socket and your problem goes away!......... Replace ALL the bulbs with a LED equivalents FTW!

FACT! The sockets are the #1 problem with these MR16’s.

 

[MikeF2316]

Measure the voltage with the lamp in place. This kind of problem is very common in automotive. There's resistance in the circuit will pass the current your meter requires, but not the current the bulb requires.

 

[yeldogt]

My guess it the socket overheated ... many are of dubious quality. I can't really explain what happens .. but, somehow the sockets get corrosion on them. Enough that the bulb will not light -- but.... when you touch the end of the socket with a probe you hit a spot where the bulb never touches -- and you see 12v.

It seems to happen to the ones from China .... shocking I know.

I'm actually using MR-16 in my new build ... I like the way they dim -- the replacement LEDs don't dim as low. Fine for situations where you want full output.

 

[Petvan]

Thanks all.. Great ideas throughout (some of which I've tried to no avail).

I have all LED retrofit bulbs which work in the 60 or other sockets. I'm going to swap the socket and see if it helps!

Cheers,

Pete

 

[cybrdyke]

Final thought...if you're trying an LED lamp in that socket and nothing in the other sockets, it's quite possible that it wont come on by itself. There has to be another lamp or two in the other sockets.
CD