EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: GGMM on September 11, 2024, 06:50:36 pm
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hello,
Has anyone ever taken care of this kind of thing?
I have since a few of my projector that does not work properly.
The detection and detection time is correct, but the LED's projector seems to blink and gives virtually no light intensity. (a little)
I’ve removed it, there’s not much coponments.
A fuse, a diode bridge with 4.7 μ 400v capacitor that must provide a rectified 220v. (Tested capacitor, OK)
The few resistors are good.
The detection command attacks a JW1691H circuit that causes the LED's to be illuminated.
https://hbaar.com/Homepage/userfiles/downloads/Datasheets/JW1691H.pdf
I think it must be defective, I appeal to your experience.
I don’t like to connect my oscilloscope on this type of thing and I do not have a isolation transformer.!
Well, its purchase price is not too expensive, it’s always the transport that makes the note explode.
Well, your opinion
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hello,
For those who are interested, here is the internal picture of the projector. Not much.
I removed the capacitor for testing (4.7μ 400v).
I think the jw1691 must be defaillant. (5 + port = 4€ at ali)
However, I do not know the type of weld used, but it must be heated to more than 400°c for this to move. The substrate looks metallic.
Out of curiosity, I took off a dead led's lamp.
Same principle, at least one capacitor and selfs to recover.
It’s a disposable.
cdt
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You can see black spots in some of the diodes which usually is a sign they have burnt up. Try shorting those out and see if the rest come back.
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Hello Drhex,
It is possible that a led is NOK. (Burned)
However, I would like to know:
Whether on a bulb or projector the DC voltage is made in the same way by a bridge.
well we will say about +300v
Knowing that on my bulb there are 9 leds and on the projector 14 and they seem in series and we start from +300v, the leds are identical?
Actually the question is, what are the references of these leds.
For the black dot, there seems to be one on the first top left. Very light, to check.
Can we get a led from the bulb and replace it on the projector?
cdt
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Usually you can just short out the broken die and the rest will light up. LEDs need a constant current so the power supply usually implements that, removing a die or two therefore reduces light output butdoesn‘t harm the other ones.
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hello,
Do you think that this led is defective (Black Dot) and can cause the flickering of others?
How is this led made. Indeed I did a test on several leds. The Diode position does not give a significant result to the multimeter, the ohmmeter position gives infinity in both directions. ??
Can I replace it with a led from a light bulb?
NB: At first sight a mark on a corner gives the meaning.
cdt
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Hello,
Today I wanted to resume the tests of my motion detector projector. I thought to have a led out of service and so test on an old bulb diswelding it.
I can tell you that it is practically impossible, the led is welded on a kind of metal substrate and if it is iron and hot air, impossible to disweld.
I then focused on the projector, same, impossible to disweld.
... And there, surprise, with the soldering iron and touching the mass of the projector, LEDs light up, even weakly. In fact all the leds seem good.
Strange, it made you think of the phase tester that we hold in our hand.
And diagnosis, no dirt in the socket I use for my work. (Oscilloscope, disweld iron, etc.).
Can the same be true for the projector?
I immediately tested my electrical outlets in the bathroom, it’s good.
To force to plug/ unplug there is maybe a false contact. YES no earth on this electrical outled. I will retest all this to morrow.
Too much noise on my oscilloscope, the solution is maybe there.
So now I’m focusing on my electrical outlets and I would like to test also my circuit breaker.
Same pb on the electrical outlet of the projector, to be seem on saturday....
cdt