Replacement PIR Sensor for Wall Lights

[Danger Phoenix]

Does anyone know where I can buy replacement PIR sensor modules for wall lights like this:

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One of my lights always stays on and another flashes a few times every time it turns off. The other two are fine though.

 

[norm]

Funny you should ask I have an ongoing issue with a pair of Eglo Sesimba 96022 lights, I've had it replaced 3 times and every time the PIR sensor component fails (I've tested it by wiring the led light straight to the mains) it switches on and then off after 2 seconds.

There seems to be some generic design for these sensors and judging by your experience they're all bad.

 

[Danger Phoenix]

I've ordered a few of these:
https://www.ledkia.com/uk/buy-presence-detectors/1095-recessed-120-presence-detector.html

Not sure if they will do the job, but no harm in trying. Definitely cheaper than replacing the wall lights

There seems to be some generic design for these sensors and judging by your experience they're all bad.

I've been tinkering with my dodgy ones by attaching a mains plug to them... if I bang the PIR modules on the table a few times, everything works for an hour or so before the same issues occur again.

 

[norm]

I would like to figure out what may have failed on the circuit. It's definitely not a case of water ingress.

Any electrical experts able to identify suspect areas on the circuit?

Symptoms are, PIR detects movement, you can hear the relay turn the led light on, stays on approx 1-2 seconds and turns off.

Even overriding the PIR by switching the light on/off at the switch twice within 5 seconds so the light is supposed to be on permanently the same thing happens.

 

[visibleman]

Any electrical experts able to identify suspect areas on the circuit?

Could be anything.
Although i'm not remotely an expert but i'd personally see if the electrolytic capacitors (black, white stripe; C3, C5, C4?) are bulging (look side on, can bulge top or bottom, not always easy to tell) and if so (do it any way to be honest), replace them as it's a cheap part (pennies) and they're fairly common to fail. Just make sure the replacements are the correct values.
Similarly with the ceramic (blue; C21) and film, i think that's what it is, capacitor (red; not marked).
After that it's a toss up between diodes, resistors, pots, failed IC (DB1 is a rectifier; no idea on the other) or the sensor itself and at that point i'd either be trying to shoehorn something else in it's place or see if i could hunt down a replacement board (STMicroelectronics maybe from a quick Google).

 

[norm]

I've had a look at the capacitors couldn't detect any noticeable bulging.

This is the manufacturer of the sensor - http://www.sensiti.com.cn/Products_show-589-115-SA003M-Standalone_PIR_Sensor.html

I do have one working unit I could possibly test and compare against with a multimeter.

As I say I've been through 3 sets of these lights and the fault appears approximately 9 months after installing. They are left always on at the mains in PIR detect mode, whether that gives any clues to a possible failure point.