Increasingly, people are wanting to learn how to construct their own computers, from components they choose themselves. Expensive and frustrating mistakes can be made in this process and therefore offering cheaper componentry to would-be system builders is a great option to make some money...with a few cautions.
This section is about how to look for, choose, test and sell second hand Motherboards and CPU's. Just this week (April 2023) I obtained one of these and am in the process of testing it.
You don't often get a chance to choose what motherboard/CPU combinations when you get them from a recycling business. For the purposes of avoiding problems, however, it is better to get INTEL CPU's rather than AMD. This is only because of ONE factor: The Intel CPU's do NOT have pins (they are in the motherboard socket) but the AMD CPU's DO. This makes them far more prone to damage, especially if they have been removed from their sockets before you get them.
Don't get me wrong - I actually am an AMD supporter - but as I get older and my eyesight worse, I find it really hard to straighten out pins on a CPU! Look at the images below to see what I mean...
Testing includes ALL ports, such as USB, video out and sound (if possible - you have to make up a system to test out sound). Otherwise, you can advertise it is working but not all ports tested. This will lessen the value.
It's also important to get all the details for the included CPU before you put on the heatsink (which you should remove, clean and reinstall with new thermal paste) and don't lose the backplate for the motherboard. I keep a large stock of these in case I get a board without one. Some can be modified slightly to fit if you have no other alternative.
AMD CPU on far left, showing the pins on the CPU.
Intel CPU Socket on the left, showing the pins in the Socket.
It's still possible to bend the pins in the Intel Socket and they can be harder to straighten than on a CPU.
To test, I remove the motherboard from the case (if it is in one). This takes away any possibility of short circuits caused by lost case screws, etc. I then place it on an antistatic bag, usually on a bench to elevate it. I install a KNOWN GOOD CPU and heat sink. testing the board without a heat sink attached is possible - you will have about 5 seconds before the CPU overheats and cooks itself though. You don't need to add thermal paste for the testing, as the heatsink will keep it cool enough for the short time you will be running it.
I always keep some TESTED RAM and install this next. One stick is enough. You may need to change slots, as some motherboards are picky about which channel they use for a single stick. I then plug in a working power supply and attach a monitor to the motherboard video connector (if it does not have onboard video, then you will need to install a basic graphics card). Plug a USB keyboard into one of the USB ports (Don't use the ones that have a blue colour, as these are USB 3 ports and may not work with your keyboard yet).
Now the moment of truth. Plug in the power supply to the wall and using a small screwdriver short the POWER pins on the motherboard. Not sure which ones? Check out the motherboard on the internet to see where they are located. Some newer boards have built in on-off buttons for this purpose. You are not likely to damage anything if you short the wrong pins.
The photos above show an older Intel board set up with power supply and running. The other photo is a screen shot showing the CPU details....also it shows that the board actually boots up! Either your board will boot up OK or it won't. It may be that everything appears to start but there is no video output. I usually attach a small PC speaker to the correct pins, to listen for the POST beep. If you don't hear this, your board may be faulty. If there are repeated beeps, then your RAM is faulty or not inserted correctly. Turn it all off and reseat it (or move RAM slots). Many boards have other beep codes to indicate things like a faulty graphics card or similar.
As soon as your board boots, press the DEL key (or F2 on some boards) to enter the BIOS setting page and check what it says. You can use this process to test out CPU's if you have a good board. Other things to test now are the other USB ports (a mouse is good to use, as it will light up) and the other RAM slots - after turning it all off before installing more of course...
This Intel CPU was from one of my recent tests. After testing, I cleaned all the thermal paste from it, took this photograph and listed it online. Before choosing a price, I looked at the other CPU's already listed to see what they were going for. There was a huge variation, from just under $30NZ to $75NZ! The ones around $75 were not selling. Why would you buy them if you can get the same thing for less than half the price?
I put my starting bid at $25. I want to SELL them, not have them sit online unlooked at and then have to relist them. It's better to get $25 than nothing.....The CPU is listed as having NO heat sink but the word "tested" is in the auction title. My 100% positive feedback will help buyers choose my product over another seller's product. This pays off. I have lost money in the past to protect my feedback (by refunding all costs, including postage and PAYING the postage to send it back) but more than made up for this in subsequent sales.