Mobo Components

I'm taking the Penn Foster repair course and it's about what I expected. Kinda lame but I wanted a guide I could use to organize my studies. I ravaged my oldish Pavilion the other day to familiarize myself with the components. One problem with Penn Foster is they show you a micro view of the component and then act like you should know where it is on the motherboard. I know there's a lot of variation but they could at least show a macro once in a while. So anyway, here's my Pavilion:



Right now they're talking chips but with very few pics for ID. So from what I've read so far this is what I'm thinking:

#1: BIOS, #2 Southbridge, #3 Northbridge

#2 and #3 had heat sinks, the larger being on #3. This reinforced my thoughts that they're the bus chips:



The suspected BIOS looked nothing like what they had on their PDF but I ID'd this (I think) by Googling the markings:



The one they showed looked like it was just a plug in but mine is seriously soldered in. So am I in the ballpark here or way off base? Any comments are appreciated, trying to get off the ground floor here. Bashan

I am not sure what your question is but my recommendation is to pick a motherboard, then go out to the motherboard makers website and download the manual for it. In the manual, there should be a figure of the motherboard layout and that should help you.

But note there are dozens of motherboard makers and 1000s of motherboards out there - using parts from 100s or 1000s of makers. We can only guess from your pictures. Note many motherboards are labeled too.

My question was if I correctly ID'd the parts by the meager information that Penn Foster supplied. I guess it was pretty much a learning exercise and had no practical application. Thanks, I'll check the manufacturers' sites.

Ah, I see. And will you be repairing motherboards when this course is done? I can see where it is necessary to be able to identify all the data and power connectors, CPU socket, RAM slots and expansion slots, mounting points, etc, just not sure the point in identifying other "surface mount" (read: permanently mounted) devices by sight, when they are not normally replaced, even if identified as bad. And again, it is not likely ASUS, for example, uses the same memory management IC or the same drive controller, or that they will mount them in the same location as MSI or Gigabyte. Certainly, you need to know what those devices do, but since it is typically cheaper to replace the boards rather than repair them, it just seems odd the need this level of detail.

If your into Motherboard Design/IC boards Design. It falls under Electronics/Engineering Technology field.

No doubt. But the OP said this was a repair course, not a EE or CompSci course.

I'm just trying to learn concepts right now. I wanted to know if I had correctly ID'd those parts based on what I'd learned. I now also know from this thread that you toss the mobo if it's bad. Thanks for the info, I'm moving on to the power supply part of the course. That ought to be easy for me to ID.

I'm just trying to learn concepts right now.

And that's a good thing!

I'm moving on to the power supply part of the course.
That ought to be easy for me to ID.

Good. Pay attention there - especially to talk about current on the +12V rail and the importance of the +5Vsb standby voltage.

Note the power supply is one of, if not the most important purchasing decisions to make when building, repairing, or upgrading a PSU. If you are not supplying quality power, everything else suffers. Sadly, too many people try to cut costs by buying cheap power. That's a mistake.

I put it this way - would you buy a brand new Porsche then fill up with generic gasoline from the corner Quickie Mart/Tobacco Hut? You might, but would you expect it run right? A car motor can miss a beat and keep on running. Not so with high-speed digital electronics.

Fortunately, the ATX Form Factor Standard dictates the shape, size and mounting screw locations for all PC power supplies. It also spells out the voltages, tolerances, and connectors. This ensures any ATX PSU can fit in any ATX case and support ant ATX motherboard (assuming enough wattage).

I now also know from this thread that you toss the mobo if it's bad.

If not still under warranty.

North bridge and South bridge have heat sinks commonly North Bridge has the bigger heat sink because its mostly active. A BIOS chip doesn't have a heat sink it only stores the information about the hard ware

For example the CMOS battery is for the BIOS when the computer is off the CMOS battery will maintain the BIOS chip.

Each PSU have 5 voltages each voltage value is related to a "rail"

+5,+12,-12,+3.3 -5

You have three major components to a Power Supply

A P1 connector (20-24) pins that supply the motherboard
A AUX-CPU connector(4pin and 8 pin) suppy the CPU when power
PCI-e connectors provide direct power from PSU to Graphic card (mainly for +12DC)

Each rail is design to pass current to the component Each rail is rated in Amp(s). For example I have a 12DC rail I will maintain at least 25As on that rail Many PSU has different amounts So its shown here 12DC@25A

For example the CMOS battery is for the BIOS when the computer is off the CMOS battery will maintain the BIOS chip.

No, sorry, but that is not how it works. The CMOS is a separate memory device. Its purpose is to maintain "CHANGES" to the program stored in the BIOS device. The BIOS device and the CMOS are two different devices and different type memory devices. The BIOS is typically stored in EEPROMs, or similar "erasable programmable" memory device. CMOS uses a CMOS device.

There is no maintaining of the BIOS. It is "burned" (flashed) into the EEPROM.

One unique characteristic of CMOS memory modules is they lose their stored data almost instantly if power is removed. Thus the battery. Note that CMOS memory modules have been used in electronic devices long before the invention of the PC. The CMOS device was intentionally chosen to hold "user changes" to the BIOS because CMOS modules are so simple and quick to reset.

A BIOS chip doesn't have a heat sink it only stores the information about the hard ware

No, that is incorrect. The BIOS stores NO hardware information, EXCEPT what is programed in by the motherboard and BIOS makers - and that is just enough to carry the boot process through to the boot drive, where specific drivers are then loaded in. The BIOS knows next to nothing about the hardware - EXCEPT basic VGA video, networking, I/O, and bus management. Your specific hardware information is saved in the CMOS.

The BIOS is basically a mini-operating system used to establish basic communications between the CPU, RAM, graphics, NIC, keyboard, and mouse and other essential devices needed to boot the system.

Each PSU have 5 voltages each voltage value is related to a "rail"

No, that is not true either. Note according to the ATX12V Form Factor PSU Design Guide, Ver 2.2, March 2005 -5VDC is no longer used. And it should be noted that some PSUs use more than one rail for +12V and some split rails. And it the current on the rail that actually holds more importance.

Quote
Each PSU have 5 voltages each voltage value is related to a "rail"
No, that is not true either. Note according to the ATX12V Form Factor PSU Design Guide, Ver 2.2, March 2005 -5VDC is no longer used. And it should be noted that some PSUs use more than one rail for +12V and some split rails. And it the current on the rail that actually holds more importance.

I had a 5 year old book copyrighted 2000 or something and professor thought us about all the currents He actually drill it in to our brains.

but thank you for the information about the CMOS and BIOS

I had a 5 year old book copyrighted 2000

2000? Well, 12 years is several generations in when it comes to electronics - especially digital electronics, and electronics that supports digital electronics.

That book may have referred to the AT Form Factor from the original IBM PC day - much different than ATX - which is getting old too, but still the standard for PCs.

Wow, thanks for the tutorials guys. I'm impressed, humbled, and afraid I may have got in over my head. Hopefully I won't have to raise to that level of expertise to repair PCs. I know you basically find the bad part and replace it but I want to understand the working basics of each part before I move on to the next. I understand the northbridge and southbridge now, they're busy data intersections and get hot as a result. The BIOS and CMOS are a little foggy but I'm putting that on the back burner for now. The course I'm taking keeps contradicting itself about this area. Here's their description in the hardwarte components module:

The basic input/output system (BIOS) is a chip that contains
the startup programs, such as power-on self-test (POST), and
drivers of the computer. This chip gets the computer system
running and interfaces with the system hardware and the
operating system. BIOS is referred to as firmware. The term
firmware suggests that the chips are neither hardware nor
software but contain elements of both. Almost all computers
include flash ROM to store the BIOS. Flash ROM allows you to erase and upgrade
the BIOS software.

The complementary metal oxide semiconductor, or CMOS,
is an onboard semiconductor chip used to store system configuration
settings, such as hard-drive parameters, memory
configurations, and the system’s date and time. It’s used by
the BIOS and located with the real clock in the system board
chipset or in a separate clock chip. The small amount of
power CMOS requires is used to retain its contents. For this
purpose, the system employs a battery when it’s turned off.

Fine, two seperate chips, one uses the other, I got it. Then in the next module there's this description:

BIOS, which is stored within CMOS (a type of microchip fundamental
to most CPUs), contains instructions for executing
the power-on self-test (POST) instructions, loading drivers for
installed devices or utilities for keyboard and monitor, activating
other ROM (such as video graphics cards), and passing
system control to the operating system. Once the OS is running,
BIOS provides OS and application access to the installed
devices.

Huh? It sounds like the BIOS is within the CMOS. I know it's a moot point, you can reset the CMOS and reprogram the BIOS so who cares where the code is? However, I like to wrap my brain around things and knowing where the chip(s) are approximately helps. Then, to further complicate things, they show a picture of a separate BIOS chip of which I have nothing like that on my board:



No real question here, just inviting comments or further elucidation if you feel like it.

BIOS, which is stored within CMOS (a type of microchip fundamental
to most CPUs)

There's the problem. The BIOS is NOT stored within the CMOS module. The BIOS is "firmware" stored in the BIOS "chip", or IC module, which is typically a EEPROM.

It is called "firm"ware because it is not "hard" coded with permanently stored data. But at the same time, it is not "soft" ware that goes away when the power is turned off - as is the case with system RAM, for example and the program Windows. These must be "loaded" every time they are used.

CMOS is not a computer term, but as you noted, a description of the device - complementary metal oxide semiconductor. The CMOS modules stores changes to the BIOS, and the RTC information. It does NOT contain the entire BIOS program.

A common misunderstanding is some folks, even misguided "experts", believe the entire BIOS "program" (the data that was "flashed" into semi-permanent memory - the EEPROM) is read into the CMOS memory during boot. That is NOT true. The two sources of data (the EEPROM and CMOS) module are used together to establish the necessary basic communications to make it through POST, then move on to the first boot device set in the Boot order.

FTR, the CMOS module is typically located near its battery.

What is BIOS?

BIOS is an acronym for Basic Input/Output System. It is the boot firmware program on a PC, and controls the computer from the time you start it up until the operating system takes over. When you turn on a PC, the BIOS first conducts a basic hardware check, called a Power-On Self Test (POST), to determine whether all of the attachments are present and working. Then it loads the operating system into your computer's random access memory, or RAM.

The BIOS also manages data flow between the computer's operating system and attached devices such as the hard disk, video card, keyboard, mouse, and printer.

The BIOS stores the date, the time, and your system configuration information in a battery-powered, non-volatile memory chip, called a CMOS (Complementary Metal Oxide Semiconductor) after its manufacturing process.

Although the BIOS is standardized and should rarely require updating, some older BIOS chips may not accommodate new hardware devices. Before the early 1990s, you couldn't update the BIOS without removing and replacing its ROM chip. Contemporary BIOS resides on memory chips such as flash chips or EEPROM (Electrically Erasable Programmable Read-Only Memory), so that you can update the BIOS yourself if necessary.

from a website
____________________

Question for OP: Computer Repair classes or courses can lead up to an Comptia A+ exam but will not go into deeply into detail about the BIOS configurations. Comptia A+ is a based line certification for entry field of an Informational Technology Technician . Are you planning on taking the courses for experience to take the exam to get certified in A+