No POST after case change

[Accessless]

I'm going to put together an old build whilst my motherboard has been sent off but I want to be sure that I don't create another paper weight by using a botched case.

Can anyone think of any electrical checks to perform on the case?

USB ports showed no crossed connections. So that's one down.

[DaveLembke]

If its pressed metal it will have round domes that are drilled and tapped, otherwise it will have the brass stand offs that are hexagonal. I prefer the hexagonal stand offs vs the pressed metal as for depending on the case, sometimes the domes are in conflict if IC legs. A long time ago I had to snip the legs of components on the bottom of a motherboard and also add electrical tape to the dome so that there was an insulator between the board bottom and the chasis metal. But with more and more surface mount parts this is usually a problem of the past, and modern boards are designed usually with a good area around the mounting holes to avoid a short to ground problem.

If its the hexagonal brass stand off type, verify that each one is exactly in reference to a mounting hole and none are screwed in... in a location where there is no mounting hole. This will cause the motherboard surface to short too ground which will cause problems.

[Accessless]

I tested with a multimeter. I thought that I got some strange readings but apparently they were well within tollerance. My old build is quite happly running in the new case for now.

May as well share the info about testing. If you connect everything up (save the power cord) and apply a multimeter to the ground pin on the mains input of your power supply, and then sequentially through all the connections on the ATX 24 pin plug, then provided you don't get a reading bellow 50 ohm all is well (excluding the black cables (ground) obviously).



I may never understand why in England we changed our power cable colours to the european ones. Red, Black, Green to Brown, Blue, Yellow & Green respectivly. Especially when in any application not covered by the same regulations uses the old colours. This does bring up a point of trivia though who's wiring system are computer/electronic systems based off?

[Salmon Trout]

I may never understand why in England we changed our power cable colours to the european ones.

It changed in Wales, Scotland and Northern Ireland as well. The UK colour scheme for 240 V flexible cords, namely live: brown, neutral: blue, earth: green (green/yellow since 2006) is not specifically "European", it's also used in Australia, South Africa, Hong Kong, Singapore, Malaysia and Saudi Arabia etc as well as the EU and is based on the international standard IEC 60446. It changed in Britain more than 40 years ago, so any equipment still using the old (red=live, black=neutral, green=earth) scheme must belong in a museum and may be unsafe because insulation that old may well have deteriorated. One reason for the change had to do with the danger posed if someone who was red/green colour blind wired up a plug. The earth (safety) conductor which connects to any exposed, touchable metal in an appliance is intended to serve as protection if a live conductor somehow contacts the metalwork. In that situation there would be a short and a fuse would blow or a breaker would trip. If the earth and live conductors were swapped in the plug, the exposed metalwork would immediately become live when the appliance was plugged in. The fuse would not blow, and there would be no sign that anything was wrong, and the applicance would probably still work. This would, of course be very dangerous. Of course nowadays we have RLCBs and moulded on plugs on many appliances. These, and the wiring colour change, are two reasons why there are fewer domestic electrocutions than decades ago.

[DaveLembke]

I have been finding these 2 types for years, but its only discovered when I cut the computer power cable to use the male plug and 3ft to 5ft of cable to replace a damaged power cord for some other device that I find the euro colors for the 3 vs the white/black/green or red/black/green when I cut through the black, grey, or beige outter jacket.

I also found out something pretty dangerous with computer power cables and that is that if you ever get one for a inkjet printer that is the type that plugs into the external power supply. Never use these as a replacement for a computer power cable.

It was discovered when a cord started to smell a short time after power up like hot plastic and was pretty hot at the plug end that instead of 16GA or 18 GA wire as is in most computer power cables, the power cables for the printer an older HP Officejet ink jet all-in-one actually had like 22GA wires at the core of the outter jacket and the computer that was drawing around 400 watts of power was overloading this light wire and so its a fire hazard if anyone decides to use a long gone printer power cable for their computer instead.