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General => General Technical Chat => Topic started by: sorenkir on September 28, 2017, 07:05:37 am

Title: What's in a OSRAM G9 2.8W LED light bulb (that only lasted a week)
Post by: sorenkir on September 28, 2017, 07:05:37 am

Hi,

This brand new nice little light bulb worked only for a week  >:(

(http://sorenkir.free.fr/OSRAM_G9/Osram_G9_2.8W.jpg)

The PCB was potted with some soft gel like stuff, easy to remove.
U1 is a BP9918B. (datasheet: http://images.100y.com.tw/pdf_file/35-BPS-BP9918B.pdf (http://images.100y.com.tw/pdf_file/35-BPS-BP9918B.pdf)):
(http://sorenkir.free.fr/OSRAM_G9/Osram_G9_2.8W_I2.jpg)

Dressed in white components:
(http://sorenkir.free.fr/OSRAM_G9/Osram_G9_2.8W_I1.jpg)

The fuse and the rectifier are OK. I will not try to troubleshoot more, as this device is not isolated at all...
Michel.

Title: Re: What's in a OSRAM G9 2.8W LED light bulb (that only lasted a week)
Post by: ElektroQuark on September 28, 2017, 07:10:33 am

OSRAM is of high qualified and of high quality devices in my list. Only a week, wow.

Title: Re: What's in a OSRAM G9 2.8W LED light bulb (that only lasted a week)
Post by: amyk on September 29, 2017, 02:56:32 am

It could be as simple as a bad solder joint. If you'd like to send it to bigclivedotcom, he could tell you more...

Osram is a very funny name in Polish. :P

Title: Re: What's in a OSRAM G9 2.8W LED light bulb (that only lasted a week)
Post by: sorenkir on September 29, 2017, 07:49:33 am

Follow-up :
- the chain of LEDs is OK, all LEDs light up,
- the diode is OK,
- the inductors are not open (both measure a few ohms),
- the resistors are OK,
- solder joints are looking OK (except one, that I have re-flowed --> no change).
It must be the IC !
When plugged, there is a high pitched irregular faint noise, but no light!
Michel.

Title: Re: What's in a OSRAM G9 2.8W LED light bulb (that only lasted a week)
Post by: HighVoltage on September 29, 2017, 08:27:58 am

I would probably open a second working one and compare measurements.
Osram used to be good quality but one can not say this in general any more.