Author Topic: KONGYO 42 LED 3W JY-388 Product Report  (Read 370 times)

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Opera House

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KONGYO 42 LED 3W JY-388 Product Report
« on: January 06, 2011, 01:31:23 PM »
I was bored a month ago and I bought s KONGYO 42 LED 3W off ebay.  It just came in today and did some tests.  Speced at 100-260V AC, it does work but probably only puts out full power  at 260V.
At 120V power was measured at only .42W (3.6ma) as measured on the 520 ohm resistor.   The circuit is 620 resistor in series with a .39uf cap.  This is rectified by a full wave bridge, filtered by a 4.7uF electrolytic and then a 520 ohm resistor to the 42 LED string. There is a 470K resistor across this to bleed it off and get rid of ghost lights.  Forward voltage on the LED string was 122V.

That is a long way from the rated 3W even if it was cheap.  The case snaps together and was pried apart.  The .39uF was paralleled with another 1uF.  Both the 620 & 520 ohm resistors were each paralleled with a 300 ohm resistor.  This brought up the current  9.5ma and the forward voltage to 129V.  This brought the wattage to 1 1/4W.  I'll try it a while like this before boosting the power since it is going in a location with poor ventilation.



I recommend that you don't buy this product and to be very cautious about buying any other product that lists operating on a wide voltage range.  If it is really cheap it won't likely have a switching regulator in it.



Rover

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #1 on: January 06, 2011, 02:24:13 PM »
Looks very similar to a 5W 60LED 12V DC that I have from ebay , uses standard type LEDs.  I wouldn't recomend this one  either.

Rover
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ghurd

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #2 on: January 06, 2011, 03:28:21 PM »
Why don't you like it?
Lower power than expected, or too blue, or?

I have one sort of like that with (around) 36 LEDs.
They did list the 110V power and 230V power separately. 
Came in an envelope.  Little "CE" sticker is the only thing on it.
Solidly glued together, and I like enough not to break it open.
I do not think they are great and did not expect great for under 8 cents per LED,
but not bad for under $3 delivered?
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Opera House

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #3 on: January 07, 2011, 08:43:33 AM »
A half watt is really dim compared to the 3W Lights of America spots I bought.  I do prefer color of those SMT types with the yellow coating.  I really wasn't expecting much but thought it would be a type that could be easily modified.  Cutting the array to three strings of 14 would make a good 48V lamp.  These snap together tightly, no glue.  A twist of a knife edge pops it apart.

I still think I posted in the correct forum.  It was less of a review as starting a discussion of modifying lamps.

ghurd

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #4 on: January 07, 2011, 11:27:19 AM »
The bulb I mentioned is 38 LEDs, rated 1.5W at 120V, 3W at 230V?
It pulls a bit less than 1.5W.

I always intended to try a lighter plug USB switcher, jumped up to about 6.6V, low value dropping resistor to deal with temp effects in the LEDs, to 2 series somewhat underdriven 1W LEDs.
Chinese 1W are pretty cheap now if you look long enough.  The color is not so great sometimes.
The last ebay lighter plug USB switcher I bought was $0.69 delivered (not here yet).

The last lighter plug USB switcher I opened had through hole parts.  Looks like a cheap and pretty simple project.
http://www.otherpower.com/images/scimages/2050/USBswitcher.jpg

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Rover

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #5 on: January 09, 2011, 08:11:36 AM »
For giggles, I just took apart the 60 LED 12v DC/AC Ebay light I mentioned above, out of curiosity on the driver circuit (Bulb is marketed as a 3W 60 LED)

components 4 diodes (rectifier circuit), 3 resistors, thats it

pretty simple ... one leg of the AC line in to one corner of a bridge rectifier circuit. The other leg through the  resistors in series totalling 7 ohms, then to the other corner of the rectifier circuit . The LEDs are fed straight from the out of the rectifier circuit

Can't trace the led connections, but there are no other resistors or components.
i'm making a guess that they are 15 strings of 4 in series

 
Rover
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Rover

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #6 on: January 09, 2011, 08:22:59 AM »
Nix that , was able to follow the painted traces, LEDs are in series of 3.

Rover
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ghurd

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #7 on: January 17, 2011, 07:24:44 PM »
I had another 38 LED bulb listed for 110 and UK grid voltages.
It had an E14(?) base and I did not get around to changing it to something I could test until last week.
It is terrible.  Can make more light with 3 decent quality, half driven, LEDs.
If it is like the ones you guys did not like, I can certainly understand why.
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ghurd

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #8 on: February 22, 2011, 08:21:11 AM »
I got a 60 LED 3W 110V CE E27 ebay bulb with the clear globe over the front a couple days ago.

The listing has a warning "(To ensure the using life of the bulb, we suggest that do not keep the bulb
continue working for more than 16 hours)".

It was pretty bright though not spectacular.  Key word being 'was'.
Lasted about 10 hours total?  Maybe twice at 2 hours, last time at 6 hours, then a few flickers leading to darkness.

Soft plastic housing.  Getting the front cover and LED board off was like punching a rubber band.   >:(

LEDs traces are arranged in circles.
Two parallel sets of 30.

110VAC in to 4 1A 1000V 1N4007 diodes.
DC to 2 caps.  Large mylar(?) and a 2.2uF electrolytic, both 400V, each with bleed down resistors.  Those resistors are 1% tolerance... LOL

A single current limiting resistor for the parallel strings of LEDs.  10 ohm 1W carbon film 5%.

Did not get a chance to measure the 110VAC input current.  Figured I had more time!

I did Not get my $1 + $3 S&H worth out of it.
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Rover

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #9 on: February 22, 2011, 02:50:19 PM »
I'm starting to see a trend now with these ultra cheap/ cheap / and even not so cheap LEDs bulb on Ebay.

Basically , save your money.

My homebuilt 96 LED (SMD5050s) has been running outside, 14 hours  a day /24/7 since I built it

Edit: Doh not "/24/7" 7 days a week
« Last Edit: February 22, 2011, 03:14:18 PM by Rover »
Rover
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ethereal

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #10 on: March 13, 2012, 11:59:38 PM »
Hi people. 
I found this topic via Google, having one of these lamps that gave a few flickers and failed after a couple of weeks. I pulled apart and could not see any obvious problem.
I put it together and tried again and it gave a single flicker and died.
It had never been on for anything like 10 hours. 
We have 240V AC and I really liked the brightness and soft light quality for my computer desk.

I do not understand electronics, but can wield a soldering iron and have succeeded with a few kits.

What part(s) are likely to have failed in your opinion and is it worth replacing any? Cost was $12, bits seem to be only cents, my time $0.00 

Thanks

OperaHouse

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #11 on: March 14, 2012, 07:21:26 AM »
One common problem with line powered electronics is the carbon film resistor used basically as a fuse just before the rectifier.  Carbon film resistors are prone to opening with surges.  Applying high currents to a CF resistor can turn it red for hours before it fails but a short pulse can pop them like a fuse.  Another common problem is an open LED.  One LED can often just be shorted to get the array to work.  Just measure voltage down the string till it changes.

My new love is 5050 LED strips.  A simple cut and paste into light fixtures.  I've bought some red 3528 strips to warm up the color of the white.

Bruce S

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #12 on: March 14, 2012, 08:20:43 AM »
OperHouse;
 The worst thing for me was finding out their the superbright LED  warehouse/store is 12 miles from where I work.
They don't give discounts for purchases at the store but shipping is cheaper :-).
I'm testing these with direct connect for my hydroponics hot peppers.
NFLS-SS-B300-1/2M-S
Easy enough to work with, nice real blue look, the reds I'm saving up for .
A kind word often goes unsaid BUT never goes unheard

ethereal

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Re: KONGYO 42 LED 3W JY-388 Product Report
« Reply #13 on: March 16, 2012, 07:33:27 PM »
Thanks Operahouse.

The LED string seems OK and the pre-rectifier resistor measures the same as printed on the board.  Is there a likelyhood that the resistor is OK when cold but fails when warmed a bit?