HI Buddie,

Hello Jestine, I have decided to write to an old friend, whom I have neglected for such a long time and for this I appologise.

No problem. It  is an honor to receive your email.

I am still building on my project, but training myself and finding out, the correct way to do things for instance :-

On the perf. board, how much solder to use, how thick the solder must be,

You can see other electronics board for reference.

how not to solder two tracks together,

Solder one point at a time and recheck the soldering to avoid double solder.

How to use the solder sucker properly.

There is only one way to use it. Press the sucker and when the solder gun tip is on top of the joint and melting, then place in your sucker on top of the melted joint/solder and press the sucker button.

The lessons learnt thus far:-  1 solder must be Thin. 2 Only feed one small touch at a time. 3 If too much solder, use the solder sucker and clear off all excess then start again,

A soldering iron with a sharp round point works beautifully,and the joints are good ( no dry joints ).

Component placing very important or the board  becomes too small. If I am satisfied I will test and if not, then I will start again till I am satisfied..

You are right!



I would like to enquire about my Samsung MP3 player.

The problem starts after it fell onto the ground a few times. I feel something isn’t right with the earphone socket. Everytime I plugged my earphone to its socket, sound isn’t heard. But after I pressed it hard, then the sound can be heard nicely.

So please kindly advise.

HI Tienny,

It seems that the circuit track may have broken. You need to open it up and check or solder back the broken circuit track.



Hi Jestine,
Glad to meet you on face book. I am an ardent fan of yours.
Jestin , Is there any way to test and confirm that an IC is faulty or bad with an Analogue or digital meter ? At least is there any instrument for testing ICs?.

The analog or digital meters could only check for the supply voltage and short circuit (ohm test). You need a scope to check for the output. You may need a huntron tracker to check the signature of the ic. There are many types of ic in the market usually it will need different tools to test it. memory ic can’t be test with the equipment above because the problem could be corrupted program



Thank you for the previous explanation . But it still remain somethings : 1 what is VCC . 2 different between VCC and INPUT VOLTAGE

HI Wakheel,

Both are almost the same. VCC is refer to the pin of the ic and input voltage is the supply to the vcc pin.



Hi Jestine,

Karean here i’m always amaze by learning a lot when i read the information that you have been sending.

Though i don’t get the time like i would like to as work do take a lot of my time. you mention telling your students to read ” Theory Books on electronics” do you have those for Sale as well ? If not can you give some idea about the best books on Electronic Theory and if Amazon.com have them for sale?



Hi Karean,

Basic Electronics By Bernard Grob. and you can get it from amazon.com



Hi; I was just wondering if you test a TA76 transistor the same way as a


Hi Marvin,

Are you referring to  this transistor array:


If yes then you can individually test it like a normal transistor. By the way TL431 is not a transistor and it can’t be tested with a meter.



Hi Mr. Yong,

Please do me a favor.

I am really in need to know how to measure the ” signal ” output at the ULN 2003A.

For eg: please see in the attachment, I’d like to measure whether there is the signal at pin 16 of ULN2003A whilst at pin 1 is input from the ASIC.

Appreciate in deed for your kind help.

HI Kyaw,

From the schematic it is a darlington array which mean that the input will be amplified and expect a higher current/voltage at the output. You can check either using scope or a volt meter at the input or output but of course it depends on what type of signal is entering to the input.


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