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I made a mistake 220 V led cob but I read 120V

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Badgers

New Member
I have attached a link to the picture of the LED module I received. It is 220 volts but it is my fault for miss reading the listing.
Is there any way to modify the board that I have to allow it to work at 120-volt?
I have pictures of the one in my hand but the image is to large for this forum to accept.

https://goo.gl/images/YbTjKP
The blue disks at the end have printed on them.
HVR 07K 471

any ideas? Since it seems the same board works for 120 or 220, I was hoping to paralell some tracks that must be in series right now.
I connected it to 120V and not even a dim glow.
thank you
 

audioguru

Well-Known Member
Most Helpful Member
The blue disks clamp input voltage spikes to 470V since 220VAC might be 240VAC and has a peak voltage of 340V. The pcb might use different resistors, capacitors and blue discs for 120VAC.

You probably have 240VAC in kitchen dual 120V electrical outlets. Make an adapter.
 

Badgers

New Member
Thank you for the insight into the surge suppressors. I am using these for lighting in my garage, and there is only 120V brought to the ceiling box from the light switch.
am I reading your response that the difference in 120 vs 220 operation is resistor and IC part numbers and not parallel vs series arrangement of the the LEDs ?
 

alec_t

Well-Known Member
Most Helpful Member
If you can't get hold of the schematic/datasheet for the module, can you reverse-engineer it, i.e analyse the connections between components to see what is in series with what?
 

audioguru

Well-Known Member
Most Helpful Member
The very big "LED" probably has an unknown number of LEDs in series and maybe has half of them with the opposite polarity so that a rectifier is not needed. We are just guessing about how it is built to have two voltage settings.
 

Badgers

New Member
so yes I have found
https://goo.gl/images/5aDLY7
for the 110V
and then 220V picture has https://goo.gl/images/1iFqqZ
I used
Xylene xylol solvent and my thumb nail to remove the silicone coating.
I need to move the chips and the sense resistors to get it to work.

scraped 80% off with my thumb avoiding where the chips and resistors are, and then the Xylene to remove the more of it without risking damaging the chip or resistor.

I am having a hard time seeing a reference mark on the current limiting IC, so I am guessing as to where it will go when I resolder it in the new location(s).
 

audioguru

Well-Known Member
Most Helpful Member
The LED COB is very cheap. For its rated 30W how will you cool it?
 

Badgers

New Member
I am retro fitting a 2 (32W) lamp fluorescent that fixture with the LED sources. I plan to remove some of the paint so I can get ground contact from the fixture to the aluminum base plate and maybe a little thermal paste to turn the 4 foot long fixture into a heat sink.
 

kinarfi

Well-Known Member
send it back an get the right one, they'll probably work with you, may even just send the correct on, other possibility is find the input traces to the COB light and apply dc, probably 30 vdc or so
 

Badgers

New Member
it costs more to return then it is worth. its more fun to figure it out then to just throw them away.
However, hedging my bets I have ordered the 110V version
 

kinarfi

Well-Known Member
it costs more to return then it is worth. its more fun to figure it out then to just throw them away.
I definitely agree, take a few photos and let us know what you find out about them, please.
Jeff
 
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