DIY PC - Tips

Tips and Tricks

Points to remember while specifying, buying and building and your computer.

SIMMS and DIMMS

Low end Pentium PCs with SIMM memory need to have their memory banks filled in pairs. If you have only bought one Simm, then the computer will not startup. The 'D' in the newer DIMM memory stands for dual, and so one counts as two of the older type.

Also, be aware that on some older motherboards, quite logical methods of filling the memory banks are not allowed. Thus, if you are buying the parts for a motherboard for which you have not yet seen the manual, stick to a simple memory configuration, such as 16+16.

SDRAM.

On a board which supports SDRAM and EDO or Fast Page RAM, there will most likely be a jumper to set to change down the voltage for the SDRAM chips. Don't forget to check for this.

RTFM

When you get the computer, read the motherboard manual big time. Highlight all jumpers that must be set, and check everything. You can't just assume that all your kit is going to work together: the motherboard may upset your plans.

Memory Banks

Filling certain memory banks with older 32 pin SIMMs can cause other banks to switch off, thus complicating the process of working out which configuration is acceptable, if in doubt get the manual and motherboard before the memory.

Prepare to solve problems.

When I opened the box containing the P133 which is running in the computer on which I am writing this page, I noticed that one of the pins was bent. Working out how to straighten it when I didn't want to actually touch it was a little tricky. The pin had clearly been bent, by someone attempting to fit the processor the wrong way around into the ZIF socket.

Suppliers sell used kit.

If you are receiving un-boxed kit, check it out very carefully. Suppliers re-sell returned goods. Sometimes, they re-sell on the basis that someone else might be able to get the item working, (as in the above example). Other times they re-sell so as to delay you, allowing them time to actually get the stock which they were supposed to have when they sold it to you.

Beware also, super-cheap memory chips: they are stolen (and lets face it, you'd be fed up if someone were using your stolen memory). Fake L2 cache-RAM, on older boards where this is not directly mounted onto the motherboard, can be checked out easily with a small utility program, so why not check yours out? Also, I am sure that pentiums could be sold as higher models than they actually are due to their ability to be overclocked so easily.

Get a proper fan for the processor...

A squeaking noise from a P133 system turned out not to be the main PSU fan, but a warning that the processor fan was about to stop working. Invest in a decent quality processor fan. However, make sure that your fan is designed for your processor, I have a very nice heatsink lying around, which would have been great on the P133, only it was designed for P150+ and would not fit on properly.

While more modern Pentiums come with built in heatsinks and fans this does not mean that you now do not have to worry about cooling. In fact, it turns out that there is now more of a problem with heat in PCs than their used to be.

Sony Trinitron Monitors

Beautiful picutre quality, but before you get one, make sure you do not mind the two fine horizontal lines across the screen, which is a design compromise with these monitors.

Make mistakes.

Making no mistakes whatsoever when building your own PC for the first time is very hard, so try to make the right mistakes! Fitting IDE or floppy cables the wrong way around will not blow anything up. Fitting the PSU cables to the motherboard the wrong way might.

Remember, the PC has evolved into a click together architecture. If something does not feel right when you are connecting it, then check it out. Look again at your diagrams and technical references. The only times I would ignore this advice is when fitting SIMMS: which never seem to want to be fitted, and when first putting a card into an ISA slot: they seem to want a hammer to put them in! Maybe, with the motherboard on a bit of foam etc it would be a good idea to fit a card into eacho of the slots, before it is actually fitted into the computer just to loosen them up a little. This might take some of the strain off the motherboard.

Fixing the Motherboard.

Make sure that the under side of the motherboard is completely insulated from the case. (Excepting the legs). This means fitting spacers into holes where there is no screw hole on the case.

When you fit the motherboard, make sure the card slots on the motherboard line up ok with the card holes in the case, otherwise you may end up putting some degree of tension on the boards in an effort to get them to fit! This is less of a problem with ATX cases, which are generally better designed than the older AT ones.

Fitting Internal Devices

When screwing internal devices onto drive bays, put the screws in firmly, but do not overtighten them since this can damage the device. Also make sure to use the correct length of screw for these devices.

Make sure that a speaker, if you have one, is firmly attached to the case. If loose, it can damage motherboard components in transit, or short out components in use.

Btw, it is worth bothering to buy a speaker should your case not provide one since if all does not go to plan the speaker will help you to diagnose the fault.

Which type of internal modem to buy.

Internal modems come as ISA or PCI cards. PCI would modems make a good purchase since the industry is moving away from the older ISA slots, however finding a PCI modem which isn't a 'software modem' (see below) is very difficult indeed.

It is also important to realise that ISA modems are not slower than the PCI versions of the same specification and are not that difficult to set up. Almost all are set to COM4 by default, and this will be suitable for most computers.

Do not by a HSP/Sofware/Win Modem.

  Modems translate data to and from a compressed sequence of tones which can be sent over the telephone network. This reasonably complex procedure should be done by a dedicated chip. Under no circumstances whatsoever are modems which use 'Host signal processing' (HSP) (where the CPU does this job) appropriate for the type of PC we are talking about building: They are a complete waste of the processing power which you have paid so much money for!

  Soft-modems also limit your computer to using MS Windows and are generally extremely tricky to set up. This last fact is partly because HSP modems are designed to be very cheap and easy to manufacture - so cheap in fact that the software controlling them is terrible, the cards themselves are shoddy and the manuals and support are almost non-existent. It is ironic then, that you can actually get a proper modem with a dedicated signal processing chip for less money than a HSP modem (when bought separately), but the suppliers still try to sell the software modems as part of pre-built systems.

  Also avoid Win-modems, which although they do have a dedicated signal processing chip, still wastefully rely on Windows software to process the higher level protocols such as error correction etc. You may think that you'll always use MS Windows, so that it doesn't matter that you can't run the modem with other operating systems, but remember that the reinstallation of working modem software will be just another thing that you have to do when you come to reinstall your broken copy of Windows.

  Question: Where do you go for new driver softare/technical support when your software modem fails? (Not the internet that's for certain!).

[Take a look at Beware Soft Modems The previous link is external to this site.

, and Winmodems are not modems The previous link is external to this site.

for more information].

A page from James David Chapman's website. Located at: http://www.users.globalnet.co.uk/~jchap/ Site mirrored here at: http://www.j.chap.btinternet.co.uk
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