Don't Miss

Computer Power Ok But No Display No POST

By Jestine Yong on August 21, 2022

Received PC for repair with fault symptom when we power it ON- CPU FAN spinning & Power LED indicator light up properly but no any other indication of Booting No POST Beep & No display.

So suspected parts are

1) Motherboard

2) RAM

3) CPU

4) BIOS

Note: Before proceeding any troubleshoot for safer side disconnected the Hard disk first. Because at the time of troubleshooting we have to switch ON & Off the machine frequently which may cause damage to the HDD. Now time to inspect the Motherboard for any physical damage.

Now first of all removed CMOS Battery, CPU, BIOS Chip and all connectors & cleaned motherboard using IPA & visually inspected the Motherboard for any type of physical damage; everything seems ok,

Removed RAM Cleaned golden contacts using eraser & inserted again in RAM slot & powered the PC but no result.

Normally on Faulty RAM it gives 3-Beeps sound indication of RAM Module failure but many time I found on Bad RAM it does not give any beep code.

Now checked Voltages On ATX SMPS connector found all voltages are Ok as per the specification i.e. 3.3V, 5v & 12v these three voltages are main required for working of the Motherboard.

Checked VRM section for CPU Voltage found 1.2V V-core Ok VTT 1.09v to CPU ok all the

Voltages are OK………….

Now I have to check whether CPU Getting HOT or not so removed CPU FAN & checked CPU by touching the finger CPU is COLD ——No Heating that means Processor is not functioning …. Here if you have spare CPU for testing will speedup troubleshooting unfortunately I do not have same Generation CPU for testing.

There is limitation of compatibility of CPU & Motherboard. I have ci5 5th Generation CPU with me but this board support till 4th Generation only……….so now I have to arrange the 4th gen. CPU for the testing.

First I decided to take the CPU on loan for testing from my colleagues but this is risky job because if motherboard CPU section is having short circuit one single mistake can cause damage to the CPU.

I kept the unit a side & took another repair………………after 2-3 days I decide to update the situation to the customer if he is ready to spend more & get the thing fix. On discussion he told me to buy second hand working CPU if possible, but I explained him other side drawbacks.

So he kept it on hold & told me he will find if any of his friends can help him to find working CPU…

On same evening I just took the CPU & thought to check the CPU if I can do something.

I took out Multimeter to check Parts Connected below the CPU …. Those all are Capacitors Connected in parallel Group wise I checked on capacitor & it showing me 2.6 Ohm ……seems like short. checked few other capacitors randomly some are showing 90 Ohm & so on…….so I removed the Capacitors which shows value below 5 Ohm……

Removed Capacitor checked out of the circuit it shows 2.46Ω a shorted Capacitor.

After removing suspected capacitors, I connected the CPU on the board & powered the unit on triggering on off switch I touched the CPU it getting HOT & I heard single Beep it indicated The board is functioning……I connected the monitor & I was in Bios setup screen……& my exhausted energy boosts up.

Randomly On & Off the power switch for confirming proper working after providing the power & seems OK. On next day I connected the Hard disk & kept CPU on Burn in test it works whole day without any problem. Updated the things to the customer about & he was excited and happy to pay me extra for this hack as I saved his machine going to the scrape.

This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.

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 repair articles on Canon LBP 2900 Printer Scanner Unit Error Fixed

Likes

(77)Dislikes

(1)

motherboard repair

18 Comments

Albert van Bemmelen

August 21, 2022 at 6:38 pm

A very professional found fix and an excellent repair Yogesh! This probably shows the possibility that many other failing motherboards may suffer from this same CPU issue. And indeed frequently switching on/off the mainboard's hdd may cause damage to it but probably foremost because of it creating failing Windows boot issues.

Likes(3)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:05 am
  
  Thanks! Albert,
  Now a days in new technology, Motherboard is causing damage the CPU also because of shorting in VRM section on the motherboard which provides working Voltage to CPU.........
  
  Likes(0)Dislikes(0)
  
  Reply
Imran

August 21, 2022 at 6:47 pm

Well done!

Likes(1)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:06 am
  
  Thanks!Imran
  
  Likes(0)Dislikes(0)
  
  Reply
Md Anisul Haque

August 21, 2022 at 8:42 pm

Nice.case study,I love this type of work,nice explain, thanks.. Please give more case like this.

Likes(1)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:07 am
  
  Md Anisul Haque,
  Thanks! for your comment.
  
  Likes(0)Dislikes(0)
  
  Reply
Arun Kumar

August 22, 2022 at 1:01 am

Great congratulations

Likes(0)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:08 am
  
  Thanks! Arun Kumar
  
  Likes(0)Dislikes(0)
  
  Reply
Gustavo Contreras

August 22, 2022 at 1:43 am

Good Job! And thanks for the great explanation!

Likes(0)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:09 am
  
  Your Welcome!Gustavo Contreras.
  
  Likes(0)Dislikes(0)
  
  Reply
Lynn Blakely

August 22, 2022 at 3:23 am

Yogesh: This repair shows that you are a qualified technician. You gave some very important things that need to be done so that the HDD, doesn't become damaged. I did wonder about removing the CMOS Battery, CPU, BIOS Chip. I am not a computer expert as you are, it seems to me that if you had checked for the chip heating up earlier that could have saved some time. You are correct in checking all the voltages first.
Thanks for the detailed explanation, excellent repair.

Likes(2)Dislikes(0)

Reply
- Yogesh Panchal
  
  August 25, 2022 at 12:31 am
  
  Lynn Blakely,
  You are Right, I did removed CMOS Battery,CPU & BIOS CHIP(which is not soldered directly on the board,it was fitted on the socket) Prior to cleaning work. I personally prefer this process because in new age technology circuit and parts gets smaller & smaller in size and some SMD parts are located very near to each other.sockets are prone to collect the dust underneath so clean it as much as possible.dust & Moisture is always cause shorting on the Board and because of this shorting there are chances to heat up any component. hence this is one of the process of troubleshooting.
  Thanks! for your comment.
  
  Likes(0)Dislikes(0)
  
  Reply
Waleed Rishmawi

August 22, 2022 at 2:13 pm

I never worked on PC computers before except to replace the whole power supply. thanks for sharing and have a blessed day. a very good job on the repair.

Likes(0)Dislikes(0)

Reply
Parasuraman S

August 24, 2022 at 12:37 pm

Very professional fix and details. The work is very intricate and needs expert handling. Good job!

Likes(0)Dislikes(0)

Reply
- Yogesh Panchal
  
  September 4, 2022 at 8:12 pm
  
  Thank you! sir
  
  Likes(0)Dislikes(0)
  
  Reply
Yogesh Panchal

August 25, 2022 at 12:39 am

Thanks!Waleed

Likes(0)Dislikes(0)

Reply
Y S Rao

August 25, 2022 at 11:44 pm

Nice repair work and valuable information from Yogesh.

My Gigabyte motherboard spoiled costly intel 7th Generation i5 processor processor a year ago. I kept another processor in the same board. It is also spoiled. I have contacted Gigabyte company for this. They said this can happen and they can repair the motherboard although it is not in warranty. From that onwards, I have opted ASUS motherboards. I have tested the spoiled processor in a good motherboard and found not working.

I have some doubt. After removing the shorted capacitors, is there any requirement to replace with new similar capacitors?

Likes(0)Dislikes(0)

Reply
Yogesh Panchal

September 4, 2022 at 8:53 pm

Y S Rao,
In new generation Motherboards chances are very high to damage the CPU because of shorting in the motherboard or Motherboard can have damaged because of shorting in the CPU. there are many factors which can cause the harm to the CPU & motherboard if problem is because of "PCH" then repair chances of the motherboard in the market are as low as 15% only & that also depends on the use & handling of BGA Machine .
Capacitors used on the CPU are just for filtering process & all are connected in parallel.it is always preferable to replace the capacitor from the donor CPU if you have. as per my personal experience i have repaired many CPU this way & they are worked perfectly without the faulty capacitor.

Likes(0)Dislikes(0)

Reply