Security Light PIR LED 220V - attempted repair (I have made things worse)

Thread Starter

John O'C

Joined Mar 22, 2017
68
Yes, I believe I shorted the capacitor causing the fuse resistor to blow.
(Photos attached)
I have not attempted any work on this, though the soldering around the bridge rectifier and capacitor look a little suspicious.

Original problem;
when working, the LEDs appeared to be pulsing. With my very limited knowledge I suspected the large capacitor. Am I correct?

I would like to get this working again (a) to learn something and (B) I hate to see usable stuff chucked out. Any help appreciated

I have been unable to source a circuit diagram for this (ZF – L3291)
 

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Alec_t

Joined Sep 17, 2013
11,984
The original problem could have been due to U1 going moody.
the soldering around the bridge rectifier and capacitor look a little suspicious.
It certainly does. Something there clearly got rather hot!
Have you done a diode check to see if the bridge rectifier has survived?
Is the MOV shorted?
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
Thanks Alec

Just remember you are dealing with a complete novice here, be gentle with me :)
The original problem could have been due to U1 going moody.
At last someone who speaks my language ... :)
Is this an jw1691h led driver chip?
Have you done a diode check to see if the bridge rectifier has survived?
I don't know how to do that, can you advise?
Is the MOV shorted?
I don't know what that means, Google was no help

What can I use to replace the blown resistor fuse, and where might I get one?

Sorry for all the questions!

John
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
After a little more Googling ....

Alec_t said:
Have you done a diode check to see if the bridge rectifier has survived?
I don't know how to do that, can you advise?
I think the rectifier is OK - 0.55v one way and O/L reversed?
 

Alec_t

Joined Sep 17, 2013
11,984
I think the rectifier is OK - 0.55v one way and O/L reversed?
That sounds ok for one diode. Did you check all four diodes in the bridge?
Is this an jw1691h led driver chip?
I've no idea.
I don't know what that means, Google was no help
Does your meter, on the resistance range, show O/L or a low value?
What can I use to replace the blown resistor fuse, and where might I get one?
A replacement fusible resistor should be stocked by any of the major distributors (Digikey, Mouser, Farnell etc). I can't make out the colour bands on the failed FR, but they indicate the resistor value. If you know that and the rated current of the LED light you can calculate the power the resistor has to handle.
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
Is the MOV shorted?
I am unable to discover what an MOV is - so not tested yet.

I will order fuse and possibly led driver chip tomorrow. I will let you know how successful I am...

Thanks
 

djsfantasi

Joined Apr 11, 2010
7,566
I am unable to discover what an MOV is - so not tested yet.

A MOV is a Metal Oxide Varistor, used to protect a device from power surges. The blue device in the upper left is likely a MOV. With nothing connected, use your meter to check the resistance across its leads. It the resistance is zero, it’s shorted out.

Here is a picture from my Google search.

EAA6BBD2-971A-42FB-AD17-0D044B489216.jpeg
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
Got it now, and just noticed MOV on the board.

Checked it and it reading a fairly unstable 4.5Megs.
Is that OK?

Thanks
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
Hello guys.
I spent about two hours today trying to source replacement parts, without success.

Can anyone help?
Parts for a 220 V LED security light with PIR (the number on the circuit board is ZF – L3291)

1: I need a suggestion for an alternative to the fusible resistor that is blown to smithereens.
I have Very limited info…
Resistor.jpg
The size is approximately 1 cm x 2 mm
there is very little left of the outside of the resistor, but from what I can see…
Possibly green or grey background
and evidence of a blue band

2: a linear LED driver chip (JW 1691H)
I need a replacement/alternative for the above, which seems to be a Joulwatt product.
JW 1691H.jpg
Thanks for reading
 
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Thread Starter

John O'C

Joined Mar 22, 2017
68
A couple additional questions…

It is a 10 ohm resistor okay as a replacement?
LED driver chip (JW 1691H): would this AL5890 work as a replacement for the original chip?
 

morphil

Joined Dec 20, 2020
2
Hello John,
I don't know if you are still interested in this subject, but I had exactly the same device to repair recently. The guilty part was one of the 14 LEDs which was open. I soldered it out and replaced it by three 2.7k resistors in parallel, and this solved my problem. BTW testing these LED needs at least 15V and current limitation (30mA). Regards
 

Thread Starter

John O'C

Joined Mar 22, 2017
68
Hello John,
I don't know if you are still interested in this subject, but I had exactly the same device to repair recently. The guilty part was one of the 14 LEDs which was open. I soldered it out and replaced it by three 2.7k resistors in parallel, and this solved my problem. BTW testing these LED needs at least 15V and current limitation (30mA). Regards
Yes, I am still interested. I will try again over the next few days and let you know how I get on. Thanks for your assistance.
Happy Christmas, stay safe.
 

morphil

Joined Dec 20, 2020
2
Hello John,
May be interersting for you : I found the Evaluation board of JW 1691H on Joulwatt website. Only the 1rst page of the datasheet is available. I requested the full datasheet and will let you kniw if they send it to me
Happy christmas, and take care
 

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