Testing and Troubleshooting

It's a good idea to test each part you add as you go along. If there are problems, you'll at least know what you changed and this should give you a good idea of how to fix it.

It may be handy to know that the motherboard can be powered up and will run without any peripherals attached at all. There's no need to attach a keyboard, internal floppy drive or anything else if you're testing out a hard disk, for example. However, with only a monitor attached, be prepared to wait up to around 30 seconds before you see the purple boot screen. My guess is that the ROMs have to time out searching for boot devices, but it could be anything.

However much you think you know about the hardware, and however long you prepare for the task in hand, you're almost always going to come across some kind of problem during a project like this. The following list of symptoms and possible causes/cures are a combination of problems I came across and some common errors which are often as easily resolved as they were made. If you have any more, please let me know and I'll add them to the list.

Symptoms	Possible causes
LEDs on the new case don't work.	LEDs only work one way, so check that the connectors are the right way round. Connecting them the wrong way won't damage anything, they just simply won't work. If it worked before, but you didn't put a resistor in the circuit, it's probably burnt out. You'll need to replace it - and fit a resistor this time!
The power LED is on, but dim, and nothing seems to work. Colourful snow effect on screen at power-up.	It could be that the reset circuit is faulty, causing the same effect as if the reset button were held in permanently. Check the connections for shorts.
Floppy/Hard drive LED stays on constantly at power up. Hard disk/CD-ROM doesn't work or isn't recognised.	Often caused by a ribbon cable being plugged in the wrong way round, which doesn't usually cause any damage. Don't forget to check other IDE devices (like a CD-ROM drive) if the hard disk LED is the problem and make sure IDE devices are jumpered as one master and one slave per channel.
Floppy drive spins briefly at power on, but won't take a boot disk.	Check that the drive is configured the same as it's connected: If it's connected to the internal floppy header, make sure it's jumper is in the "0" (zero) position. If it's external, check the jumper reflects this (note however that daisy-chained external drives are usually set to "1"). If you're using a PC floppy cable, check that you have a straight connection. Don't use the connector at the end after the twist in the cable.

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