Can anyone ID a replacement transformer for this JMR-5 (120v 277v)? Or if not the exact one, some that can replace it from digikey.com? It's buzzing like crazy and i want to replace it, rather than buy an entirely new light for $80. Thanks!

 

If the problem is due to loose lamination rather than (over) current, what you could try is de-solder it and lay it in a small tray of conformal coating with the terminations exposed and let is soak for a hour or so.
Remove and let dry.
Max.

 

Lay just the connectors on the base in the solution? Recommend any particular conformal coating? Thx.

 

Can anyone ID a replacement transformer for this JMR-5 (120v 277v)? Or if not the exact one, some that can replace it from digikey.com? It's buzzing like crazy and i want to replace it, rather than buy an entirely new light for $80. Thanks!

Are you sure it is the transformer and not the relay (blue block) making the noise? It looks like a capacitor fell off the board (behind the blue block). If you lost the filter cap on the DC side for your 5V coil, you might get a very annoying racket.

 

Lay just the connectors on the base in the solution? Recommend any particular conformal coating? Thx.

The one I use is by M.G. Chemicals, it is quite fluid.
Make sure the terminations are sticking up out of the coating.
Max.

 

Are you sure it is the transformer and not the relay (blue block) making the noise? It looks like a capacitor fell off the board (behind the blue block). If you lost the filter cap on the DC side for your 5V coil, you might get a very annoying racket.

Well you are correct. I went over to my office tonight and hooked it up and it was the blue one vibrating and making the buzzing. I Found the item on https://world.taobao.com/item/524973657987.htm. Where is the best place to pick one of these up at?

 

Well you are correct. I went over to my office tonight and hooked it up and it was the blue one vibrating and making the buzzing. I Found the item on https://world.taobao.com/item/524973657987.htm. Where is the best place to pick one of these up at?

I'm not sure the transformer is dead, it may simply be vibrating because the capacitor somehow fell off the board. The capacitor should smooth the DC low voltage (6 volts or less) that is supposed to power the coil on the relay. Without it, the energy to the relay coil may bounce all over and cause the relay to shutter.

Look at the capacitor symbol between the two empty holes on the pcb. Check in the back side if there is bare copper by those holes (solder never applied and capacitor never installed) or silver with solder and the capacitor apparently fell off the board.

Once we know the history of the capacitor, we'll have a better idea of the relay needs to be replaced or the capacitor needs to be replaced.

 

Here are two more shots of the board. Looks like there was solder on the back of that JP1 where nothing is there, but i see none in the plastic housing that fell off.

PCB FRONT
PCB BACK

 

R6 looks overheated and the reverse side of the board it is under.
The vacant spot looks like is for a jumper.
Max.

 

The resistor the Max mentioned above does look concerning. That resistor should be changed but also look at
1) the solder joints on that resistor. They don't look like nice little cones like they should.

2) the center solder joint of the transistor in the bottom left of the image below looks like the lead was not clipped close enough and the longer-than-acceptable lead may be crunched over to the adjacent pad on that same transistor.

Bottom left - check group of three (center pad looks poorly clipped and shorted to adjacent pad...

 

I see what you are talking about on joint not being clipped close enough. Do you happen to know what kind of resistor or a way to match up the color bands maybe? The cheap light is a Model# RMR-16-WP just an FYI...

 

I see what you are talking about on joint not being clipped close enough. Do you happen to know what kind of resistor or a way to match up the color bands maybe? The cheap light is a Model# RMR-16-WP just an FYI...

Try bending the little bit of transistor (base) lead away from the collector pin. Then check if the relay stops clicking. Something is causing the resistor to get hot and the relay to stop working. I'm guessing it is the poorly clipped lead on that transistor. A quick bend will test the theory. It is possible that nothing has to be changed once the extra length is clipped and short is addressed. (Or even just bend it out of the way a do don't cut anything).

 

I looked in detail and no contact is being made between solders. Grabbed another angled photo for better reference also and added yellow circles around the resistor that looks burned.
PCB BACK 2

 

Any transformer with the same voltage/amp ratings with 6V coil voltage.

Also, the resistor should be replaced with one of same resistance but higher wattage (0.5W). Also, when you solder I to the board, keep the body of the resistor about 1/4" off of the board so it can circulate some air and wont turn the board brown.

I dont have time to reverse engineer the circuit to see what that resistor does. Look closely to see if you can figure out the band colors. Or, if replacement boards are available, you can check those if clear photos are online.