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Identify a broken Zener diode?

Posted: 09 Oct 2021, 02:55
by Wyattlin
Hi, all
Something about Zener diode. I have found that the door lock switch of my '98 Hyundai Accent has been damaged by water (sealing issues). I used Wurth Contact OL to remove rust but one of the components of the board has got broken while I was trying to remove the rests of the product with a piece of paper. I believe I can carry out the soldering work but I cannot identify the broken component. My searches (according to Testing and Distinguishing Zener Diodes Overview) lead me to believe it is a zener diode, but what kind? There are no markings on it.
(My conclusion from search source: https://www.kynix.com/Blog/How-to-Test- ... iodes.html)

I have thought about asking the local shop to give me a selection of the most common types and go the trial and error way, but I am afraid I could fry other thing... So, could someone guess, by the pictures of the board, what kind of component I need to have all the doors of my car closed in one move like in the old good times?

Thank you in advance.

Re: Identify a broken Zener diode?

Posted: 09 Oct 2021, 09:36
by Tomg
No way to know what the zener is without a schematic and/or parts list. There appear to be other concerns such as missing copper on at least one rotary switch pad (remember to check the mating wipers for corrosion), a corroded connector contact (remember to check the mating connector pins for corrosion), a possible bridged gap (hard to tell from the photo), questionable looking electrolytics and perhaps a few transmigration problems. I know you would like to save some money by replacing just the zener, but replacing the entire board is probably your best long-term solution. Are new boards still available for purchase?
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If you are planning to make a career out of saving PCB assemblies think about purchasing a decently-sized ultrasonic cleaner. They can be expensive, but are fairly effective in removing environmental contaminants without inflicting excessive trauma to the board.