Need help with troubleshooting low-volt recessed lighting

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lightitup

Member
Location
Minnesota
A couple weeks ago I go on service call for new new customer.
Situation: four recessed lights, in vaulted ceiling over kitchen island, on one switch. One light "hasn't worked for a while" another one works "some days" other two working fine. I place drop cloth and 8' step ladder on top of island (straddling built in sink). Pull down trim assembly, Juno IC926 sloped can, Juno # 617 trim, 12 volt MR 16 lamp. 110 volt present at socket. I ohms out transformer (screws into 110v) and lamp and seam to be OK. I tell H.O. I'll reseach further and check availability of replacement trim - transformer.
Later back at office, I screw assembly into table lamp - at first it didn't work, but after "wiggleing" lamp it lit. I picked two replacement MR-16 socket leads thinking ends must be "pitted" and not makinging good contact with lamps.
Next day I send out my worker to install - they both worked all is well. At least for a while.

H.O. calls a week later and says "The one that hasn't been working for a while is working fine, however the intermitant one now quit working after to days." Sent my worker back on friday (3rd. trip) Thank God, H.O. is very understanding, and even as giving us other little projects to do while we're there. Worker calls me, lamp is good (interchanged with working light) and 12 volts present at socket ends.

The only thing I can think of is open windings on Xformer - but only under load.??? I called Juno tech support - they never heard of a problem like that.
Replacement transformer available, or replacement trim available (comes with magnetic transformer). Not stocked at my supplier - special order - and spendy.

Have any of you run across this before?? Any sugestions.?
 
stickboy1375

stickboy1375

Senior Member
Location
Litchfield, CT
lightitup said:
A couple weeks ago I go on service call for new new customer.
Situation: four recessed lights, in vaulted ceiling over kitchen island, on one switch. One light "hasn't worked for a while" another one works "some days" other two working fine. I place drop cloth and 8' step ladder on top of island (straddling built in sink). Pull down trim assembly, Juno IC926 sloped can, Juno # 617 trim, 12 volt MR 16 lamp. 110 volt present at socket. I ohms out transformer (screws into 110v) and lamp and seam to be OK. I tell H.O. I'll reseach further and check availability of replacement trim - transformer.
Later back at office, I screw assembly into table lamp - at first it didn't work, but after "wiggleing" lamp it lit. I picked two replacement MR-16 socket leads thinking ends must be "pitted" and not makinging good contact with lamps.
Next day I send out my worker to install - they both worked all is well. At least for a while.

H.O. calls a week later and says "The one that hasn't been working for a while is working fine, however the intermitant one now quit working after to days." Sent my worker back on friday (3rd. trip) Thank God, H.O. is very understanding, and even as giving us other little projects to do while we're there. Worker calls me, lamp is good (interchanged with working light) and 12 volts present at socket ends.

The only thing I can think of is open windings on Xformer - but only under load.??? I called Juno tech support - they never heard of a problem like that.
Replacement transformer available, or replacement trim available (comes with magnetic transformer). Not stocked at my supplier - special order - and spendy.

Have any of you run across this before?? Any sugestions.?
Click to expand...

Never had any problems with juno, but did have problems with other brands, always turned out to be socket related problems, seems they cant take the heat of a 50w/MR16 lamp.
 
W

wireguru

Senior Member
look at the pins on the lamp, are they pitted? If you put a lamp with pitted or burned pins in a new socket, the new socket will go bad over time.
 
L

lightitup

Member
Location
Minnesota
"look at the pins on the lamp, are they pitted? If you put a lamp with pitted or burned pins in a new socket, the new socket will go bad over time."

Installed new lamps and new sockets.

"Check the connections in the j-box w/ the branch circuit."

Shouldn't be problem - 12 volts at socket
 
L

lightitup

Member
Location
Minnesota
480sparky said:
Without load.... with a load may be different.

OP stated 110v at socket, however, as well as 12v. ????
Click to expand...

If I understand your responce correctly, Yes 110v at Can socket, and 12v at Mr-16 socket (after transformer)

"Thermal unit in can opening or becoming intermittent?"

That was my first thought, but with power at 12v socket wouldn't that eliminate the thermo cut-out? Wouldn't lamp light, than open cut-out when it heats up? With 12 volts present at low voltage socket - the thermo cut out must be closed - right?
 
mdshunk

mdshunk

Senior Member
Location
Right here.
lightitup said:
"Thermal unit in can opening or becoming intermittent?"

That was my first thought, but with power at 12v socket wouldn't that eliminate the thermo cut-out? Wouldn't lamp light, than open cut-out when it heats up? With 12 volts present at low voltage socket - the thermo cut out must be closed - right?
Click to expand...
I'm not at all famaliar with these screw-in transformers, but I might guess they necessarily have a thermal overload unit of their own that might go open from time to time if they overheat.

You using good lamps? ie, something from one of the big players and not the Heng Chen Electrical and Housewares Company.
 
L

lightitup

Member
Location
Minnesota
mdshunk said:
I'm not at all famaliar with these screw-in transformers, but I might guess they necessarily have a thermal overload unit of their own that might go open from time to time if they overheat.

You using good lamps? ie, something from one of the big players and not the Heng Chen Electrical and Housewares Company.
Click to expand...

Marc - Thats what I was wondering too - built in cut-out in transformer - but you would think lamp would light for a little while then open? Cheap lamp from H.D. however lamp is good - we interchanged with other fixture and it lights.
 
480sparky

480sparky

Senior Member
Location
Iowegia
lightitup said:
If I understand your responce correctly, Yes 110v at Can socket, and 12v at Mr-16 socket (after transformer)
Click to expand...

What I'm saying is you are measuring 12v at the bulb socket, but there's no load on the transformer at that point. Once a load is placed on the transformer, the voltage may drop to zero.... indicating a poor connection.
 
C

CopperTone

Senior Member
Location
MetroWest, MA
had a similalr situation 2 weeks ago, I simply removed the fixture, and bought a whole new one. the material bill may have been a little more for the customer, but the labor charge was a lot less and i only went there two times, once to look at the work and once to go back and repair the work.
no call backs.
 
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