Hardware problems



1 A plug in card won't insert properly

 Problem: See also Boot up Problem 6. If the problem is at the metal plate end check that the end of the metal plate isn't fouling the case. Often you have to bend the end of the metal plate on the end of the card to make it fit. If the card doesn't fit snugly and wobbles when plugging in a peripheral you can also bend the plate to make it fit tightly.

2 Your new modem won't work

 Problem: Lots of modern modems need MMX processors with their extended instruction set. An older processor often won't work with a new PCI modem whether its a "software" or a "hardware" type. I haven't found any ISA modems that don't work with older processors so if all else fails get an ISA modem. Unfortunately they're always more expensive because there's not as much demand for them.

3 Windows can't find the CDROM.

 Problem: Sometimes you need to read a CD but the drive isn't detected. This can happen in SAFE MODE or in a re-installation of Windows. Windows always REMs out the MSDOS CDROM commands in the start up files at some point in its setting up procedure. If you put these back the CDROM will usually be available when you need it. You can also use the CDROM setup floppy to reinstall the lines in AUTOEXEC.BAT and CONFIG.SYS for you. This will set up the proprietary driver folder as well.

4 General peripheral problems following a Windows Upgrade

 Problem: I've found that an upgrade from Windows 3.1 to 95 usually worked OK but a subsequent upgrade to Windows 98 lost one or more bits of hardware ie. display, sound card or modem. Sometimes the problem will appear during the addition of an entirely unrelated piece of hardware later, when an earlier device will disappear never to be seen again. The problem may be insurmountable and you will need to get a newer card with a Windows 98 driver.

This can be really annoying if an older non-IDE CDROM plugs into a lost sound card. The computer tells you to insert a CD but you can't because you needed the CD to install the CDROM! It's a black art sorting out sound card CDROM interfaces especially the non-IDE types. In the early days one could never be sure what the interface on a CDROM drive was. It was labelled "INTERFACE", "BUS", "CONTROLLER", never very specific. Some where even serial interfaces with smaller connectors. The original floppy disks carrying the drivers may have been lost aeons ago or they may now be unreadable. Nothing's worse than spending ages looking for an old floppy only to be rewarded with the message "can't read from specified drive" or the dreaded shunting noise from the floppy drive as it searches fruitlessly for readable data. Be prepared to chuck the old sound card and CDROM drive away.

5 You can't get a new hard drive to work as you'd like.................click the valve to see a full guide to fitting a large hard drive..

 Problem: If the processor is less than a decent Pentium or equivalent you may not be able to see more than 8Gbyte. If the processor is a 486 or older, the new drive may not be recognizable in the BIOS anyway. Some hard drives come with special software embedded on the drive or on a floppy. This will configure the setup of the drive in the installation procedure to make it recognizable. However to use a partition size greater than 2Gbyte you have to use FAT32 which is available in Windows 98 or late versions of 95. Once a drive has been partitioned in FAT16 you can make it FAT32 with a Windows utility but not vice versa. You can change partition sizes with proprietary software such as Partition Magic but consider reformatting if you want one big partition instead of lots of smaller ones. Unless you know for sure that your motherboard can see a large drive don't get one bigger than 8Gbyte.

6 System is unstable and gets worse and worse with faults being pretty random. Software build is small or beyond reproach.

 Problem: Your motherboard may be on the way out with an intermittent hardware fault. This may be a temperature dependent failure or it may be merely a poor back-up battery guarding your CMOS contents for proper boot up. Alternatively, your memory may be intermittently faulty and be causing a variety of problems. Be warned that sometimes a memory or motherboard diagnostic won't always pick up a random intermittent failure. Often, faults don't materialize out of thin air but are induced by plugging in a PS2 keyboard or a PS2 mouse when the system is powered up and BE WARNED also that most, if not all, ATX systems have standby power applied to the motherboard when they are ostensibly powered off. Unless the mains power lead is removed or the rear mains switch (if fitted) is turned off never plug or unplug anything from the computer box. One exception to this rule are USB connectors which can be plugged or unplugged when power is on. Another reason for faults appearing is static damage to memory, processors or motherboards. Some environments such as a warm, nylon carpeted room, will allow a huge static charge to be built up on ones body. This charge may end up down a pin of a memory DIMM unless proper precautions are made. One should only touch computer parts when handled in conjunction with a proper antistatic workstation and an earthed wrist strap unless you are prepared to take the risk of destroying expensive acquisitions.

7 Odd system crashes after overclocking the processor

 Problem: Before the advent of un-overclockable processor-motherboard combinations one could speed up the processor. Some people advocated this and others issued dire warnings with meltdown overtones. As a rule you should operate your system at its rated specification. If it's cold in your computer room an overclocked processor may work but when the ambient gets warmer things may go wrong. Taken to the limit...imagine playing a blow lamp on the processor. Sooner or later it WILL stop working.. COMPLETELY. Before then it will think about going wrong and sometimes actually hiccup. Really hot chips like AMD and Cyrix operate just on the limit. Anything slightly off and they will fail. Clock rate and heat are intimately linked... up the clock rate and up goes the heat. It's also admitted that some processors are selected. All will pass the lower clock rates, some will pass a higher clock rate and a few will go all the way. If you operate a selected 500Mhz chip at 600MHz it WILL fail. This may merely be that for one complex instruction an internally generated pulse is a little late arriving at a gate input and an arithmetic addition didn't happen. Sooner or later the instruction gets used and the program didn't get the right result and stalls because the programmer never anticipated the outcome.

By the way always check the fan is rotating. These are sometimes of dubious quality or may even have a cable intermittently fouling the blades. If a fan stops the processor will as well but only when a combination of ambient room temperature, heatsink efficiency and the proximity and temperature of your central heating radiator conspire to gang up. With a bad fan, Intel chips will soldier on longer than the AMD/Cyrix/IBM varieties.

8 The floppy drive doesn't work

 Problem: This is an old problem that may be getting forgotten about now. If the floppy drive is unplugged for any reason make sure the cable is the right way round when you plug it in again. This goes for hard drives and CDROMs also! Usually the coloured line on the edge of the cable marks PIN 1. Usually PIN 1 is next to the power connector. This isn't always the case though. Also if the other end of the cable is the wrong way round you will be confused so first check the motherboard end is orientated correctly and is seated properly. Look at the back of the floppy drive and see if there's a digit marking the end of the connector. If there is you can fit the plug without trouble. If there's no marking you have two possibilities. Trial and error or further investigation. As (most of) the pins down one side of the connector are at ground potential and are all connected together you can check continuity (with the power cable unplugged). The row of pins connected together should be noted and then the motherboard measured in the same way. Then you can connect the cable making sure the rows of grounded pins on the motherboard connect to the grounded pins on the floppy drive. However, using the trial and error method is quicker. If the cable is the wrong way round the LED on the front of the floppy will be always lit. If the cable is OK the LED will be out until the drive is accessed.

If you hear the drive being accessed with the LED flashing, and there's a disk in it and you can't read it you may have a duff drive. Don't forget to try another floppy disk before consigning the drive to the dustbin and of course the disk must be formatted before the computer can read it. Floppy drives do wear out, usually starting intermittently before finally expiring. If you have a really old machine the drive may use a rubber belt to turn the disk. These wear out and are probably the most common reason for dumping an old Amstrad. The belt, however, can be replaced quite easily.

Finally on the subject of floppy drives. Their cable is usually quite complicated. To start with most cables still allow for a 5.25 inch drive to be connected. This is to the thicker of the two connectors. Very new motherboards are now starting to be supplied with only 3.5 inch cables but still of course with the funny twisted bit at the end. Traditionally, floppy drives are addressed by two bits at the end of the cable. It was long ago discovered that if you called two drives, Numbers 1 and 3 you didn't have to fit special jumpers to the back of the drive to make it respond to its address. Instead you made all drives look like address 3 and the "3" was changed to a "1" at the end of the cable by twisting the address wires round. This means that you MUST fit a single drive to the END of the cable not the connector half way down. If you didn't do this then you've not stuck to the convention and there's the reason for the "faulty" floppy drive.

9 The hard drive doesn't work

 Problem: Bearing in mind what I said about floppy drive cables above, you can also make a mistake with hard disk conventions although these aren't as universally clear cut. It's often rather crowded inside a computer case and its really easy to mis-plug an IDE cable. Sometimes the pins on the board are surrounded with a plastic shell. This is even polarized so that a cable can match and be inserted only one way round. Unfortunately not all cables are polarized and occasionally there are but they're the wrong way round! Confirm that the coloured cable marker is next to PIN 1 which is usually marked on the motherboard with a little triangle. A lot of motherboards don't have the plastic shell though and its really easy to plug a cable in with only one line of pins sticking in the plug. The others are in free space! You can also inadvertently miss the connector longitudinally and leave the end pair of pins sticking into free space! Check visually the cable is plugged in correctly if there's a problem and any doubt.

Next we'll look at the other end of the cable. At the hard drive PIN 1 is universally next to the power connector. However on the hard drive, either at the back next to the IDE pins OR on the hard drive circuit board, are a set of jumpers. These are for telling the computer what's going on. Usually the drive will be set as a MASTER but it could be set as a SLAVE. Sometimes there's a bit of logic to sort out as not all manufacturers have the same ideas. Most manufacturers write instructions on the hard drive label telling you how to set the jumpers. Unfortunately English is not always their native tongue and the instructions are not worth reading except as a general guide. If you're trying to add an extra hard drive as a slave to your main drive you will have to change the jumper fitted to the new drive as it'll almost certainly will be set as master. There may be not one, but two jumpers to set on the slave drive. There may also be a jumper to set on the old master drive as well, telling the computer that there's a slave drive present.

Adding a slave drive is not always easy mechanically as the IDE cable is nearly always too short. If this is the case try switching it round by putting the short end in the motherboard and the long end to the new drive because the position of a drive on the cable isn't important like a floppy. Either drive may be connected to either connector. In fast machines though it may be advisable to use the end connector for a single drive system. This is to do with reflections bouncing off the unterminated end and getting mixed up with hard drive signals. On this point I always advocate leaving cables in a scrambled condition rather than neatly tying them in bundles. Crosstalk between two signal wires is less when the two are furthest away. Make sure the loose cable can't foul the processor fan however as its easy for a stray edge to stop the blades turning!

10 Difficulty reading a floppy disk

 Problem: A difficulty now not much in evidence is floppy disk compatibility. Someone I know, who should have known better, used to drill a hole in the top corner of 720k disks. He could then format it as a 1.4M type. Sometimes it worked. For how long however was debatable. Back in the mists of time were a whole range of floppy disk varieties, very big 8 inch, 5.25 inch and the newer 3.5 inch. Some were double sided and some single sided. All proclaimed to have superlative capacities. This led to a problem. Having already coined a word for the density you had to then define a word that described a better capacity. Unless you know this fact you may think that "double density" is the bees knees. Usually you come across just two types nowadays. Both are 3.5 inch. The standard type has two holes in the top edge and the other a single hole. The former is known as a 2 Mbyte capacity type and can hold 1.45Mbytes of formatted data, the other 1 Mbyte which holds 720kbytes of formatted data. Special format programs can squeeze a little extra (like the crate load of disks used in Windows 95 upgrade). There is also a 2.88 Mbyte type that hasn't really caught on and other types used for backup purposes, however I'll concentrate on the common pair.

The 720k disk drive uses a different set of physical, electrical and magnetic standards to the 1.45M type and the disks have different magnetic coatings. 720k heads are fatter and lay down a wider track than 1.45M heads. Follow the instructions and you can usually format a double density disk in a high density drive and it will seem to work. By crafty application of long since defunct MSDOS commands you can dictate a bespoke format structure on a disk in either drive type. I've even formatted a 3.5 inch disk that thought it was a 1.2M 5.25 inch type. All this CAN be done but if you want to preserve your data for more than a few days you must use 720k disks in a 720k drive and 1.45M disks in a 1.45M drive. Cutting an extra hole in the top of a disk doubled its capacity, and if you had the good fortune to format it you'd probably have had the bad fortune to find it unreadable a few months later when trying to load a rare driver. Transporting the two disk types between the two drive types is a hit and miss procedure and should only be done if no alternative exists. If you have valuable information on double density 720k disks, copy it to your hard drive and back it up on high density 1.45M disks and it'll be safe.

In the unlikely event you have 5.25 inch floppies and a suitable floppy drive the same goes for compatibility. 180k, 360k and 1.2M disks etc. should all be used with their proper matching drives if you want reliable results.

A little-understood thing among computer users is the thumping doinging sound you get when you turn on a monitor from cold. To demagnetize the screen and stop misregistration with the consequent rainbows and blurring around text and the edge of images a heavy magnetic pulse is applied around the cathode ray tube whenever a monitor first receives its mains supply. The pulse has a significant power and can wipe or degrade floppy disks placed in the vicinity. NEVER place a floppy disk on a monitor and NEVER place a floppy disk under the front or at the side of the screen. Data will be corrupted to the extent the disk may not even be formattable ever again. Even when a monitor has been switched on for a while there's still a residual current passing round the degaussing coil which may, over a period of time, wipe a disk.

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