The Big Parts on a Mobile Phone’s PCB
On the “Mobile Phone Parts Functions and Identification,” We are going to be looking at the big parts. The big parts here refer to the ICs short for integrated circuit. It is a good skill to be able to identify mobile phone parts functions for troubleshooting purposes. Additionally, this knowledge helps in communicating faults in phones to clients with a more professional approach, this is a technical skill, so you don’t have to act like a “zombie” when dealing with complicated devices.
It’s a well known fact that the major problem technician’s encounter is identifying the mobile phone parts functions and other stuff on the PCB! Knowing how to pin point parts straight away makes your work fast and easy, but the problem here is that there are very few phone manufacturers who are willing to make their schematic or block diagram available online.
Nokia, Samsung, Blackberry and a few others have most of their block diagrams online to help with for both in-house and third-party engineers and technicians. For Tecno, Gionee, Infinix, Itel, XBo, and so many others, you will have to depend on experience and forums to tackle such cases. The good news is that once you get used to working on different devices, overtime you become familiar with the mobile phone parts functions and their other aspect and expert at locating stuffs.
Now let’s learn about these big mobile phone parts functions and how to identify them on the PCB to know what they really do in a phone one after the other.
Mobile Phone Parts Functions and Identification:
Power IC: The problem resulting from the power IC can be very tormenting and can even give you high blood pressure especially when dealing with an expensive phone you vowed to conquer. The power IC is an important micro-chip found in the power section of all mobile phones. The power integrated circuit is the component electronic chip that distributes required value or measure of current voltage to all other parts of the mobile phone. Though manufacturer architecture may differ, you will mostly find the power IC close to the battery terminal in phones with inbuilt battery and most times you find it either behind or at the top of the PCB in SIM facing up position when the PCB is screwed. It is mostly protected by a silver plated metal. You will observe that the power IC normally have so many capacitors, resistors, and a good number of coils etc of varied shapes and sizes which helps in proper and accurate distribution of current needed for healthy functioning. If the power IC is bad, that is “bad market” and the beginning of sorrow, the phone will go dead and only God can help you in this battle if you don’t know what to do! See how to fight dead phone “kpalaba” here just in case it happens eh!
CPU: Just like the Computers, phones too do have CPU known as central process unit. This IC controls and co-ordinates program instructions and all other activities that goes on while the phone is being operated just like how you have got a brain in your big head that determines how every other thing goes on hahaha…just joking sha. If the CPU gets shorted or affected by a hard fall from the top of Mount kilimanjaro or everest, or a water damage while attempting to cross the red sea, or corrupted software file “wahala” from going here and there like Lucifer the arc enemy of mankind, it may result in a dead phone! The CPU is also referred to as RAP, UPP or MAD IC , Oh! but don’t get it twisted, am not talking about insanity here but something related to your brain anyway. The CPU can be found in black color. The CPU is unique in its size in most cases as it appears to be the largest IC chip on the PCB like and elephant is in the forest. Just like every other crucial ICs, the CPU is protected with a silver coated iron plate so that its life can be free from the troubles and struggles of this world.
ROM: Not the “ancient Roman Empire …o”, it’s the Read Only Memory; this is where the operating system software program instruction is resident. The program instruction in this section is also coordinated by the CPU making sure that all programs load correctly. If the ROM IC is faulty, the phone will start misbehaving like someone needing psychiatric doctor and may become dead if He fails to come on time.
RAM: RAM, not the “ILeya festival” one you are thinking oh! The Random Access Memory is mainly responsible for sending and receiving operating system command while the phone is being operated. It can be found in the power section. The RAM IC can be affected by a hard fall on the floor or when its being heat hard by a real Ram you previously thought of, or short or water damage etc. the RAM can go dead if the problem persist and nothing is done about it.
Flash IC: This integrated circuit can be found in the power section of a mobile phone and is also referred to as EEPROM, Memory IC, ROM and RAM. When flashing of software is done on a phone, this is the software hardware component that accommodates the system software. A faulty Flash IC results mainly in software problem or power. If this IC is not replaced, even if you flash the phone a million times, you are just wasting your time! After trying all your “juju” and it doesn’t come back to life, then get it ready for wake-keeping and finally burial ceremony.
Charging IC: This IC is found in the power section of a mobile Phone; it receives electrical charges from the phone charger to charge the phone battery which is passed on to power IC after passing through the power and zener diode, resistors and caps for further distribution to other parts in specific values. If the charging IC is bad or going “AY” the phone will not charge properly or may not even charge at all even if you “speak in tongues”. If the phone’s charging IC gets a short circuit, the phone won’t be able to power. Some shorted diode in the power section can also cause power problem when they get shorted as well. Sometimes, charging problem could be so complicated that you might start thinking that someone in the village is collaborating with witches in the city to make sure it doesn’t work in your hands. Bro, or should I say Sis.? Our eyes have seen many things in this work. Anyway, it is well.
Logic IC /UI IC: The Logic or user interface IC found in any part of a mobile phone controls the operation of internal parts like the phone vibrator, ringer and the LED in a mobile phone. If the logic IC is bad, there will be problem with the listed parts which it controls. I remember the first time I jumped up from my chair and ran away when my first ever bought SAGEM phone with antenna rang and vibrated in my pocket while I was playing ludo with a friend….wow, so embarrassing when I found out it was the phone vibrator that almost made me enter “market place”!
Audio IC: This is also referred to as the Melody or Cobba IC, you did not hear me say cobra ooo….snake bit is not our portion this year! This IC controls the phone’s mouthpiece and ringer. When this IC is shorted or faulty, the speaker and mic will not work. This is the problem that makes people scream like those in hell fire when they are not heard at the other caller’s end thinking their shout will repair the phone…hmmm. This may even cause the phone to go dead as a result of this IC problem.
RF (Radio Frequency) IC: Let me take you now in to the world of the spirit! This “black thing” (RF IC) is also known as Hagar, “not the concubine of Abraham”, the woman in the Holy Books. RF signal processor or Network IC as it is called, can be found in the network section on the PCB. While controlled by the CPU, it works as both transmitter and receiver, I did not say “transmission transmission, oh sorry sir, I mean” of audio and radio waves (meaning that you are about to fly now into the spirit) or the world of signals which makes user communication possible. When this component is faulty, network will not be stable or strong and can result in power problem when the IC is shorted. Welcome from space journey!
VCO: Short for voltage controlled oscillator. This is found close to the network IC of the network section in mobile phones. This Chip acts like a gate man that keeps watch of your movement to know if you are a suspect or that you should be killed immediately. The VCO controls and regulates the sending of time, date and current voltage to the radio frequency IC as it receives signals or command from the CPU of the mobile phone. When this component is faulty, it results in “call end” or “call failed” as you will see in some phone while you are at this job! Phone “gbege no go kill us oh”!
26 MHz Crystal Oscillator: Hmm… sounds like the magic Indian voodoo crystal. It is also known as the network crystal and is found around the PFO in the network section. You will observe that this component is mostly shinny and has metallic make-up. It is this component that creates the frequency that makes an outgoing call possible when a user is engaged on the order end. When this component is faulty, one won’t be able to make a call and network also will not be available and then your phone becomes an MP3 player or iPod. When it is shorted you can experience a dead phone situation too.
RX Filter: The RX filter is also found in the network section of a mobile phone and filters frequencies during an incoming call. When this component is faulty, incoming calls will be impossible due to weak or no network frequency; you can find the RX filter test point on the PCB in the event of a broken path or so, and is useful when flashing feature or basic phones using miracle box pinouts.
TX Filter: This is the sibling to RX, it has to do with the outgoing end. This component is responsible for filtering electronic signals or frequencies during an outgoing call so you don’t get all that humming bird distortion or stuffs like “oga the line dey break o, abeg call me back”. When this component is faulty the network may be noisy or call may not even get through at all. The test point is a gate way just like the RX test point when flashing feature or basic phones using the rx tx cable in software boxes.
Antenna Switch: This component has both metallic and non-metallic make-up. It can be found in the network section of a mobile phone. You can identify it by its color which is either silver or golden. It usually performs the function of searching network, tuning and then sending forward. When the antenna switch is faulty, there will be network problem in the mobile phone even “if you go climb” MTN mask to get network.
Power Amplifier or P.F.O: This component is also found in the network section of a mobile phone. It is also referred to as the P.A. (Power Amplifier), just like the one used in party to boost your loudspeaker during a party or an ”owanbe”. This component is responsible for filtering, amplifying and selecting the country home network of a mobile phone; e.g. MTN, Airtel, Glo etc. When the Power amplifier is faulty, a network problem will also surface and calls will be difficult or impossible due to network problem. When this problem happens, replace the PA or get ready for the next MP3 or iPod device in your hands.
Mobile phones do not have single identification formular for all models. You learn to know them by their schematics and diagram layout coupled with experience, you are able to spot and differentiate parts on your own!
Now that I have succeeded in giving you this entire lecture narrative on mobile phone parts functions and identification from an African perspective, even if the phone “carry course or bad luck come met you, you go deliveram”! if you still didn’t understand anything I have said so far, then “na only you woka come”! Please go ahead and succeed in your carrier! You will hear from me in the next updates on this.
This indeed is a veritable and an innovative platform for a mobile phone quick fix.Tech Usman is a rare geek we the buddy phone tech must take more serious. Please Sir, i wish to belong to your Whatsapp group. Add me up 07059504511
vous etes le meilleur merci beaucoup
Thank you for this wonderful piece. Please sir, my question is, power ic, network ic, and other ic’s, are they available for purchase in the market.
And do you advice i resolder these Ic’s ?; Because I only check the cars level parts. Thank you sir
Yes, mostly for samsung, iphone, lgs and a few other flagship devices. Google to know more… ICs can also be reworked!
Thanks bro it realy helpful: Phone power IC changed due to just showing red light and won’t power on but now okay.
Can you provide a link to download G. S. M repair guide book
Thank you for making it easy for us begginers, atleast now i can differentiate parts.
can we communicate on whatssap with this # +264813974322.
I like your write up really helpful and funny . God bless you.
Thanks a lots sir, I found this post beneficial.
Where can I find your book mr Musa Usman
There is a new link for that on the blog!
Sorry pls, the link is now active.
This is so resourceful. I have been gambling about these big parts as you call them but am gonna do my best to Master each of them. Am looking forward to being a good phone technician. Thanks
Wow, I’m impressed. This is a refresher course for me. Very interactive and educating, I like the touch of comics in the teachings. From an African and for Africans. kudos man…
Please I really need to know the all the I. C an the functions an probably their image
Please someone should help me out
I’m Impressed with this… as if u purposely wrote it for me….
Is all right
You are a great teacher i must give you that…how i wish you had taught me repairs. I really need softwares and dongles and i hoping you can help me get them please… Am hoping to hear from you. Thank you
Thanks very much for the lessons… This is very detailed and I wanna learn more from you since I am very new into phone repairs and wanna make sure I do a very good job for my customers… I have a tecno k7 which connects to a computer but don’t show nothing on the screen and also doesn’t show charging when you connect a charger… Steady power comes onto the battery terminal but not display and also the phone doesn’t switch on when you press the power button… Hope to hear from you soon…
Service with rework station with more focus on the CPU/Memory ICs, also check first for possible short of capacitor or diode, missing component etc.
Can you allow me know your books please