Master 2 points: first, look, second, test

First, look

1. Look at the monitor model and try to buy monitors from well-known brands such as Sony, Mitsubishi, IBM, DELL, HP, EIZO, SUN, and SGI. As we all know, although only Sony and Mitsubishi (Trinitron and Diamond) can produce high-end picture tubes, many well-known display brands have OEM products from these two companies, such as Sony's G500 monitor

2 ． Look at the product appearance and production date.

The appearance of a second-hand monitor should not be too worn, otherwise it will lose the value of purchase. Of course, do not pursue the newness of the casing too much. Because second-hand monitors are more or less subject to wear and tear after being transported and stored in multiple stages, it would be really questionable if the casing is too new! We recommend that when purchasing, you can ask the merchant to open the outer plastic casing and take a look at the picture tube and circuit parts inside. The color of the picture tube of a monitor with better quality will be darker, and there should not be too much dust on the circuit board. Of course, this is also related to the environment in which the monitor was originally used. There should be trademark, serial number and other information on the back of the monitor. The most important of these is the production date of the monitor. It is recommended to buy products that have been used for no more than 3 years, so as to obtain a higher return on investment value. In addition, stains, fingerprints, etc. on the surface of the display may be unavoidable, but it can be wiped off. Then check whether its sealing and interface are satisfactory, whether the casing has been squeezed and deformed during transportation, and the coating of the display screen should not fall off or Marks of severe scratches. If it meets the above conditions, it’s basically OK. After all, this is a second-hand product and you can’t compare it with new ones.

If we want to know the parameters and information of a monitor, we can get it from the nameplate of the monitor. Generally, the nameplate is affixed to the back of the color display case, with the monitor's production date, model, voltage, performance, and origin printed on it... But for some older monitors, JS will tear off the nameplate or remove the date and the like with the naked eye. The numerical value that can be used to determine whether it is good or bad is scratched off to deceive users. For JS, we can identify different models. For SONY DELL second-hand monitors, we can long press the meu menu key (about 5 seconds). At this time, the BIOS information inside the monitor will be called up. We also You can see the production date, model, voltage, performance, serial number and other parameters. If this method is invalid, we can also read this part of the information through Powerstrip, Aida32 and other software.

Second test

Testing of second-hand monitors

The appearance can be slightly more accommodating, but the quality of the display effect cannot be ignored at all, otherwise it will violate the Our original intention of buying second-hand monitors. For monitors of different sizes, you should test them at different resolutions. The 17-inch is 1024*768, the 19-inch is 1280*1024, and the 21-inch is 1600*1200. Of course, this is not the highest resolution that the monitor can achieve. So the purpose of this test is to know how well these second-hand products display under normal working conditions? Of course, in the end, it is not a bad idea if you insist on setting the monitor to 2048*1536 to take a look.

For monitor testing software, we still recommend NOKIA TEST. Generally, second-hand monitor merchants should provide it. If they say they don’t have it, then be careful. It is very likely that they don’t want to use this monitor. The problem is exposed in front of you, so friends who have the conditions should still use a flash drive to make a copy and take it with them.

Focus: This is what we need to pay most attention to. Generally, second-hand monitors that have been used for a long time or have been refurbished will not have a very good focusing effect.

The focus test screen looks like this. You can compare the clarity of text displayed in the middle and four corners of the monitor. Generally, all CRT monitors have the same focus effect on the four corners. It is not as good as the center of the screen, which means that the text displayed in the four corners will be slightly blurry, but if you find that the font in one of the corners is particularly blurry and cannot be adjusted, then you need to pay attention, because this is very likely It's an old picture tube.

In addition to focusing, you should also pay attention to the convergence effect. Convergence is divided into horizontal convergence and vertical convergence, which can generally be adjusted separately. It is easy to see whether the display has convergence problems by using the renderings in the test software. Intuitively, a monitor with poor convergence will have a faint red or yellow color fringe when displaying images (especially text files). Some monitors have convergence adjustment, and you can try adjusting it when you buy it.

There are also some issues that need to be carefully checked when buying a second-hand monitor, including: geometric distortion at the corners, moiré, temperature drift, breathing effect, etc. of the monitor, but these are relatively less demanding. Harsh, as long as the effect is satisfactory, it is acceptable.