Don't Miss

An Expensive Faulty Board Repaired And Maintained

By Jestine Yong on February 4, 2024

A guy brought this device for repair. He said that it does not work but he did not mention anything about the board like what does it do so I did not bother to ask.

He bought the power this supply and when I checked the output voltages it was up to specs so the issue was in the board itself.

I powered the board through this power supply and checked for voltages input on board but there were none. So I am facing this kind of issue that the power supply is up and running but the moment I plug it into this board no input voltages on board which is a clear indication that this board was shorted pulling the voltages down.

I connected the board through an external power supply and I used my new purchased thermal camera (sorry no photo here) and right I was I could see a hot spot on the input of the board.

I added a heat protecting tape and I used my hot station to take that shorted part off.

That is the shorted part that was causing the problem on that board. That tiny piece is a filter and when I checked it with a multimeter, it was showing reading on all of its legs causing a short on board.

These kinds of filters are found in play stations and very easy to locate. The one that I have is a little bit bigger and somehow I will manage to solder it on board.

The filter fitted perfectly on board and once the soldering was done, I powered on the board using power supply that the customer brought and this time the voltages were there.

The customer was with me in the shop the whole time and the moment the board was ready to be checked, he took it back to his place and gave me a called later that day that the board is up and running.

It think it is a board for some kind of blood checking machine but no details about but most important it was working fine and the customer was happy.

Mission Accomplished.

This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment.

P.S- Do you know of any your friends who would benefit from this content that you are reading now? If so, forward this website to your friends or you can invite your friends to subscribe to my newsletter for free in this Link.

Note: You can check his previous article on A Full HD Car DVR Does Not Power Up For An Obvious Reason Repaired

Likes

(60)Dislikes

(0)

pcb board

13 Comments

Patrick Ribbsaeter

February 4, 2024 at 9:44 pm

Good job.. another one in the bag

Likes(3)Dislikes(0)

Reply
- Waleed Rishmawi
  
  February 5, 2024 at 5:17 pm
  
  Patrick: thanks man. yes indeed. have a blessed day
  
  Likes(1)Dislikes(0)
  
  Reply
Yogesh Panchal

February 5, 2024 at 1:06 am

Good Job! Waleed
Majorly this type of filters found in Nintendo Switch.

Likes(2)Dislikes(1)

Reply
- Waleed Rishmawi
  
  February 5, 2024 at 5:18 pm
  
  Yogesh: thanks man. I do not have parts for the Nintendo switchs so I managed with this one. have blessed day
  
  Likes(2)Dislikes(0)
  
  Reply
Parasuraman S

February 5, 2024 at 8:36 am

So, you became a technician's technician, eh? (LOL)nVery good elevation in status! The kind of work you handled and troubleshooting you did cannot be done by normal technicians. It requires years of experience and expertise! Well done, my dear friend and thanks for sharing!

Likes(7)Dislikes(1)

Reply
- Waleed Rishmawi
  
  February 5, 2024 at 5:19 pm
  
  Parasuraman: yes I did..LOL. thanks for nice comments. have a blessed day
  
  Likes(3)Dislikes(0)
  
  Reply
- Imoudu.O
  
  February 6, 2024 at 11:38 pm
  
  Good repair acticle, i want to presume finger touch can't detect the filter's temperature.The use of higher current with low voltage is additional gain to me, thanks for sharing.
  
  Likes(1)Dislikes(0)
  
  Reply
Albert van Bemmelen

February 5, 2024 at 7:35 pm

You probably connected the board through an external power supply that could provide a much higher current than the original power supply that came with it to be easily able to find the hotspot. Probably because the original power adapter limits its current because of the detected short.
A preferable method also good to track shorts in laptop mainboards. And if such a short is for instance on the 19V DC input port we beside the higher current can also increase the external supplied voltage to the same 19V voltage. Or to the voltage that shorting circuit normally would need.

I believe those filters are often also used in tracks to USB ports.

Likes(6)Dislikes(1)

Reply
- Waleed Rishmawi
  
  February 6, 2024 at 2:49 am
  
  Albert: yes I did as it is mentioned in the article. High current but low voltage. I used a thermal camera to spot the short, removed and replaced with a good filter. Have a blessed day
  
  Likes(2)Dislikes(0)
  
  Reply
Tayo

February 5, 2024 at 10:31 pm

Well done Waleed. I recently purchased a thermal camera for just such a repair. Cant wait for it to pay for itself!

Likes(2)Dislikes(0)

Reply
- Waleed Rishmawi
  
  February 6, 2024 at 2:49 pm
  
  Tayo: thanks man. thermal camera is a very good investment and it will be for itself. have a blessed day
  
  Likes(1)Dislikes(0)
  
  Reply
moshe jacobson

February 6, 2024 at 7:02 am

Another Great job (& article)!!

this may be a silly question...but...i don't notice any gull wings on the filter chip, so, how did/do you solder it to the board?

Likes(2)Dislikes(0)

Reply
- Waleed Rishmawi
  
  February 6, 2024 at 2:52 pm
  
  Moshe: thanks man
  if you look closely to the photos given you will see the solder pins on the bottom of the part and to solder the part on board you need a rework station..have a blessed day
  
  Likes(2)Dislikes(0)
  
  Reply