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October Repair Newsletter

By on October 4, 2008

If you are a first time visitor to my blog and wish to read my October repair newsletter that talks about “How To Build A Cheap, Simple And Yet A Powerful Zener Diode Tester” then you can click HERE to subscribe to my monthly repair newsletter and you could also read all the previous repair newsletter too. See you in the other side! Have a good day!


Questions/answers for the project and testimonials:

Thank you very sir for October repair news letter. but i would like about the fuse is that 13 amperes?

Yes it is 13 amperes main fuse.

how about the led what is the volt rating that i will buy?

this is the normal LED and should be about 2 volt

is three pin plug necessary or two pin plug ok?

Yes, it is okay to use a two pin plug since the ground is not necessary

thanks sir God bless you more for your sharing your tips,techniques generously. i hope for your answers

You are welcome!


Thanks Mr Young Your are always the best

But i have question,
what about a bad zener diode?
Sometimes i have a bad zener diode, but i dont know his voltage, and i havent a schema diagram for a circuit
For example, a power suply for CRT monitor, i have make a zener diode minimum voltage and i increase, and finally it’s 9 v (and the monitor is good)

Hi Adlene,
That was a good question. In fact if the zener diode shorted or burnt and can’t see the part number then it will take a longer process to locate the exact voltage. Apart depending on schematic, the other way is to understand the overall circuit by using a quite similar schematic. For example if the zener diode in CRT Monitor power supply have problem, we can easily conclude that the voltage is arounf 18 to 24 volt!.


Hi Jestine,
From what online vendor can you buy the linear transformer showned(230/24V) in your recent monthly newsletter?

Hi David,
I bought it from my local electronic shop and no idea which online shop selling it. However you can check from the list of electronic suppliers from my blog at


Hi good day I recieved your zener diode tester and Im very much thankful for that. its a great help for me as a technician more power and god bless you always thank you.


Jestine Yong – first I want to say thanks for that little blackbox you call Diode tester.Did not think it can do so much – man this was just what I needed, small but all in one —-tnx again.

Yes my everything you do also turn out well.




Dear Jestine:
thank you a lot for this simple & effective testing circuit since till now i test the zener with small circuit  using oscilloscope but this work better .
really zener diodes are components that needs to be checked mostly in power supply circuit and this must be done quickly and in reliable method , i really look for circuits like this in testing these small components because these components are important and in the same time testing them is boring .

also i face a big problem in testing smd transistors ,capacitors and resistors i never have experience with smd components .

best Regards




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