*********************************************************** * Build Your Own SCSI Tower with a CD-Rom & Hard drives * *********************************************************** $VER: SCSI Tower V1.0 (Written by Anthony Keeley) Remember the above header and how I basically told you how you could build your own SCSI tower out of a PC case and drives? Well, I got several responses from you and because of this, I feel that a more detailed text was needed. So I've updated this text and added new sections. Please read on.... *********************************************************** * Build Your Own SCSI Tower with a CD-Rom & Hard drives * * WITH (more) DETAILS, COMPARISIONS and a FAQ * *********************************************************** $VER: SCSI Tower V2.0 (Written by Anthony Keeley) Adding extra externally mounted drives to your system is one of the easiest things to do, and it doesn't have to cost the high prices charged for simply putting the bits together: and when I say easy I mean EASY! If you can use a screwdriver and push connectors together, then you can build yourself a SCSI Tower. Also, at the end of this text is some information on installing an external floppy drive into the tower (you'll require a working external DF1:): and some useful information on how to power your Amiga from the tower. Disclaimer: ~~~~~~~~~~~ Whilst every effect has been made to ensure that there are no errors in this document and because of its technical nature, the author can not be held responsible for any damage arising from your usage of the information provided. If you require further help or assistance, then you are welcome to contact the author at the email address provided within the document. Thanks: ~~~~~~~ For a start, I'd like to thank a good friend from his electrical abilities, for installing the power connector into the PSU: and for doing the laborious job of soldering all those wires to make up a 23 way straight through cable (46 pins). Secondly, Dave Collingwood in believing that the original SCSITower text was good enough to include in his `DCA1200T.lha' file. Thanks for the compliment! (Does that keyboard hack work with the Amiga Technologies A1200?) And.. to those of you who kept my brain ticking over by sending me questions about SCSI drives and the numerous faults that people can come up against: but SCSI's are still easier than IDE's :) Requirements: ~~~~~~~~~~~~~ An Amiga. Whilst this document can be used by PC & MAC people, the software referred to is Amiga only. PC & MAC users will have to refer to your own manuals on how to set up the drives etc. A SCSI Controller with an external SCSI Port. External SCSI Drive(s) and/or SCSI CD-Rom Drive (both is better :) 1 x PC Case. (Shape and size dependant on your requirements/cash) 1 x SCSI ribbon cable. A pre-made ribbon with 7 x 50 pin connectors on. (with connectors) Preferably with an 8th connector This 8th connector should really be a Centronics 50 way female connector. 1 x 25 D-type female connector to a 50 way Centronics male connector. If you're using the Squirrel SCSI interface (A1200 & A600) you don't want the last cable (25-50), as the Squirrel is already fitted with the correct type of connector. But you may want a 50 way male centronics to 50 way female centronics extension cable, as the Squirrel cable is very short (.5m long). Tower and Desktop Cases: ~~~~~~~~~~~~~~~~~~~~~~~~ PC cases come in all shapes, sizes and shades of grey and cream: and depending on your needs and desk space will be which box you finally purchase: a FULL, MIDI, MINI tower or DESKTOP case (and which one your cash flow allows). The `desktop' boxes and `mini' towers usually cost roughly between £30 - £40 (check out the ads in MicroMart 80p). `Midi' towers range from £40 - £60, and `full' towers from £50 - £100. Desktop 3 x 3.5 1 x 5.25 200 + watt PSU These are only a guide to the MINI 4 x 3.5 2 x 5.25 200 + " " drive storage of a case, it MIDI 5 x 3.5 3 x 5.25 200 + " " may vary. Check with the FULL 5 x 3.5 4 x 5.25 200 + " " vendor before purchasing! Note: The FULL tower can hold more drives than the SCSI controller can use. If you have a spare 3.5 drive space you could always install an external floppy in it as DF1: and power that also from the tower (How to install a DF1: is documented at the end of this SCSI text). Buying a tower/desktop case will only be affected by how many drives you want to install into it. If you decide that you'll be simply fitting 2 x 3.5 SCSI hard drives and a single CD-rom drive, then the cheaper mini tower or the desk top case will be ample. If you want to install 2 x CD-rom drives, 1 x 5.25 SCSI hard drive, and 2 x 3.5 SCSI hard drives, then the minimum you'll need is the midi tower, as neither the mini or desktop has enough 5.25 drive bays to accommodate your designs. As to the wattage of the built-in PSU, forget it. New standard PC case comes with a 200 watt psu minimum: some have even higher rating: some even weigh in at a tidy 350 watt. Consider that the A500 came with a massive 60 watt psu and the (Amiga Technologies) A1200 comes with an even greater 25 watt psu, then a 200 watt psu is going to be ample to drive 7 SCSI devices, 1 floppy drive and an Amiga 500/+, 600, 1200. For those who've got the big box machines, you have even less power problems. SCSI Drives: ~~~~~~~~~~~~ Hard drives come in various sizes, 5.25" FH (Full Height. You'd know one as soon as you see it - 3") and HH (Half Height - 1.5"): whilst the 3.5" come in HH, 1", and Slimline. Quantum produce a drive called a BIGFOOT, which I've seen in IDE form, but not yet in SCSI form. But that doesn't mean they aren't made in SCSI. A Bigfoot is a 5.25" slimline and is very large capacity drive - Gb's. Each of the above drives will take up 1 drive bay except a FH (full height) drive will take up 2 drive bays. As for CD-rom drives, they come in 2 sizes. Yes, 2 sizes, both 5.25":- a 1.5" drive (normal size) and 1" (laptop size). The type of SCSI connector on the drive is very important, and they do come in differing guises. The standard SCSI 50 pin connector, the IBM edge connector. The condensed 50 pin SCSI 2 connector, and the various other connectors for SCSI. The type of connector we'll be using is the standard 50 pin connector as shown here. ------------------------~~~-------------------------- 49 | o o o o o o o o o o o o o o o o o o o o o o o o o | 1 50 | o o o o o o o o o o o o o o o o o o o o o o o o o | 2 ----------------------------------------------------- If the drive you plan on buying doesn't have this type of connector, then don't buy it, as it wouldn't fit onto that nice ribbon cable you bought earlier. SCSI Controllers: ~~~~~~~~~~~~~~~~~ The various Amigas could have a number of SCSI controllers. Even the small box machines (A500/+, A600/A1200) could have several different controllers. And as for the big box machines the choice is even greater! Listed here are just some that each of the machines could use. It is not a complete list and personally I don't think any single person could compile a comprehensive list that covers everything. Machine Controllers Device driver Supplied software A1000 A590 scsi.device HDToolBox * A500/+ A590 scsi.device HDToolBox GVP HD8 II+ gvpscsi.device Faaastprep A600 SquirrelSCSI Surf Squirrel squirrelscsi.device HDToolBox A1200 Same As A600 Accelerator boards such as the Blizzard, Apollo, Falcon etc all take a SCSI controller each having their own type of device driver. Big Boxes A2090/1 scsi.device HDToolBox A1500/2000 GVP HC 8 gvpscsi.device Faaastprep A2500/3000^ And any other Zorro II scsi controller... A4000/4000T Big Boxes All Zorro II scsi controllers... A3000/4000 A4091 scsi.device HDToolBox And any other Zorro III scsi controller * The A1000 could have the A590 attached on the right hand expansion port at the side, but the A590 was facing to the back of the unit. ^ The A3000 came with a built-in scsi controller, & I'm led to believe that the controller's SCSI ID is actually `0' and not `7' like most of the other controllers. But I'm also told that this can be changed using the built-in software. Putting it Together: ~~~~~~~~~~~~~~~~~~~~ The Tower or Desktop case you buy will most probably have the PSU disconnected from power switch at the front: and this will be a four (4) connection affair. Simply follow the connection diagram on the PSU for connecting the wires up.. Before you start putting anything into the case, check that the SCSI ID's of each of your drives that you intend to connect, including any drives that you already have connected, do not match with another drive that will be on the same controller. If you already have a SCSI controller in use and plan on extending it into the PC case, `HDTooBox' will list all the drives on that particular controller. WRITE THEM DOWN, BEFORE YOU SWITCH OFF! With all the internal drives I've seen, ID's have to be changed using jumpers either next to the SCSI connector (CD drives), or on the circuit board (hard drives). Referring to the manual/A4 sheet that came with the drive (you did get one didn't you?) will tell you where the jumpers are and how to set each ID correctly. AND.... for those of you who, like me, bought their drives second hand without instructions.... SCSI ID jumpers come in a set of three lots of 2 pins. They can be anywhere and they can be part of a row of other jumpers. But there are clues as to where they are: as is the case with Quantums which have a row of six jumpers. And the ones marked A0, A1, A2 are for the SCSI ID, whilst the other three have other uses, such as PARITY etc. Ok, you've located the ID jumpers and want to work out how to change them to a particular ID. The following chart will show you which jumper has to be open (Not Connected) and which has to be closed (Connected) to get the correct ID. We'll use Quantums marking for this chart.. \ ID 0 1 2 3 4 5 6 7 \ Jump \ A0 O C O C O C O C O = Take the Jumper Off A1 O O C C O O C C C = Put a Jumper On A2 O O O O C C C C (ID 7 has been listed for those who have a controller whose ID is `0') Getting the SCSI ID's correct is half the battle won. The other half comes in various shapes and forms which I'll tackle later. Change the ID on the drive(s) so there are no matching ID's. The controller is usually ID 7 so don't use that. The drive that came with the controller originally (if it came fitted) should be ID 0. (See later about changing ID's) Most CD-rom drives come set as ID 2 or 3. Change these to the highest ID that is available. This depends on the controller's ID and how many CD-rom drives you plan on connecting to your system. Open your PC case and install the drive(s) into the appropriate drive bays, not forgetting to connect the power connectors. Both the SCSI and Power connectors will only fit in one way due to their design, so DO NOT FORCE them in. With Tower Cases, the fastening screws are provided and you should use four screws for each drive installed. Desktop cases can vary on how drives are installed, so check before you buy that you'll have everything provided in the initial purchase. Get your internal SCSI cable and connect it to the drives. Common sense will tell you how to connect the drives to the cable. If you can't manage this, I'd give up and find someone who knows. Before closing the case, you'll have to determine how to get the connector to the outside of the case so you can make the connection to the controller. With Towers, the ribbon cable can sit between the outer casing and the frame of the tower. Or, both the tower and desktop cases have a section for expansion cards to be fastened to. Most should be removable, so you can put the ribbon cable under the frame to the outside world. DON'T refasten the screws too tight near the cable. Another option would be to dismantle the connector, pass the ribbon through one of the back plate openings and rebuild the connector! This last option is NOT recommended. Finally, you can now connect the external scsi port on your controller to the connector at the back of your case using the 25 to 50 way cable. The Squirrel's connector should connect directly to the connector at the back of the PC casing without a problem. Don't put the casing back on yet, but first boot up your Amiga and watch and listen very closely. Your machine will take some time to boot the first time due to the drives not being set up under AmigaDos, and the controller trying to determine what on earth a CD drive is and why it wasn't told about it. OR YOUR MACHINE DOESN'T LIKE YOU ANY MORE AND THINGS DON'T WORK AS PLANNED! FAQ: ~~~~ What is FAQ, well FAQ stands for `F'requently `A'sked `Q'uestions. Personally I prefer the more accurate `Aaaaaarrrrrggggghhhhh! WHY DOESN'T IT WORK...!' Problem : Your machine simply won't boot... Cure 1 : Switch on the PC case Cure 2 : You've managed to allocate a drive ID the same as your boot drive. Cure 3 : A termination problem (see later - Termination) Uncure 1 : The drive's logic card has such a big clash with the controller that they both refuse to work, and the machine fails to boot. OR Problem : Your machine boots but HDToolBox doesn't see the added drives... Cure 1 : Switch on the PC case. Cure 2 : SCSI Cable not connected. Cure 3 : Wrong SCSI device set in HDToolBox's Icon. Cure 4 : SCSI ID set to the same as another drive (not the boot drive). Cure 5 : A termination problem (see later - Termination). Cure 6 : The Block size on the drive has been set to 1024 (usually 512). Later versions of HDToolBox could handle 1024 byte blocks. OR Get a PC user to reformat the drive with 512 byte blocks Uncure 1 : The drive added is a non-worker. Uncure 2 : The drive added won't work with your controller. OR Problem : Your machine displays a purple screen with a floppy being inserted into a floppy drive..... Cure 1 : Switch on the PC case. Cure 2 : SCSI Controller not connected to Amiga. Cure 3 : Possible loose SCSI connector, or Power connector. I've only ever suffered this problem once, and the first thing I did was to check the connections and try again: the machine booted. Cure 4 : A possible termination problem (see later - Termination) OR Any or all of the above problems can be caused by the ribbon cable being ripped where it joins the actual metal pins inside the connector. If you suspect you have got a ripped cable, then you can try one of two things to find out. Firstly you can take a multimeter and test each and every even numbered connector pib: or if you have a spare connector which sits inline before the suspected connector, connect your drive to this one, remove any drives after the suspected one, and switch on to see if this has cured your problem! So you've managed to boot up, and HDToolBox has found the added drives but says they are UNKNOWN. Brilliant! Exactly where you should be (unless they were already used on another Amiga, in which case HDToolBox should say they are CHANGED). Using HDToolBox click on the UNKNOWN drive and then select 'Change Drive Type'. Now select 'Define New': select 'Read Configuration' and the boxes should fill with the information required by HDToolbox to work with this drive. Select OK, and then 'Save Changes to Drive'. If you want to partition the drive, away you go and divide the drive up into as many pieces as you want by selecting 'Partition Drive'. Repeat this process for all UNKNOWN Drives. Quitting from HDToolBox will force a reset, but this is so the system gets to recognise the new drives. For the CD-Drive, you'll have you use one of the CD filesystems provided; such as Xetec, AsimCDFS, AmiCDFS. Or you could simple use CBM's dos driver (if you have Workbench 3.1). If you do use CBM's Dos driver, remember to change the device and SCSI ID in the tool types of the icon to match the correct device driver and SCSI ID. One final reset and everything should be working ok. But your boot up will take longer because of the added drive(s). CD Hints: ~~~~~~~~~ 1. Don't put your CD Dos driver into the DEVS:DOSDRIVERS drawer. Put it into SYS:STORAGE/DOSDRIVERS, this will allow you a faster boot up: and if you need the CD, you can simply double click on the icon. 2. If you do have your CD dos driver in DEVS:DOSDRIVERS, put an Amiga CD in. This will help reduce the boot up time. Termination: ~~~~~~~~~~~~ I would like to quote a passage from a FAQ text on the SCSI standard about termination and how it works. Then I'll tell you how I work with the SCSI termination (or how this standard does NOT work as it should). - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - There is a simple 'guideline' (see below) to termination: No matter what (1Drive, 2Drives, 3Drives/2Cards), only the devices at both ENDS of the SCSI chain are to be terminated, all the rest are not! Here are a few examples, terminate the [ENDS] ONLY! [END]Controller-----Device[END] [END]Controller-----Device-----Device[END] DO TAKE ANY CHANCE AND TERMINATE THE BUS PROPERLY EVEN IF IT MEANS UNSOLDERING THE TERMINATORS ON THE CONTROLLER! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Errr Yes! Thats how the Termination standard should be implemented and if it works for you, DON'T change anything, BUT.... SCSI termination is a very BLACK art, and for a very good reason! SCSI termination works on the principle that both ends of the chain should be terminated to stop signal echo's. A simple example would be as in example 1 Terminated Terminated -------------- -------------- | Controller |----------| Hard drive | -------------- -------------- But if you add a second drive, example 2 should be the result. Terminated Unterminated Terminated -------------- -------------- -------------- | Controller |----------| Hard drive |----------| Hard drive | -------------- -------------- -------------- Sadly, as the chain gets further from the controller, Termination "rules" seem to go out of the proverbial window. Looking at my present setup (I've only got the one tower now, with 2 CD-rom drives and 3 Hard drives) which uses a non-standard termination sequence with the Classic Squirrel: Terminated terminated Unterminated Unterminated -------------- -------------- --------------- --------------- | Controller |----| Hard drive |----| CDRom drive |----| CDRom drive |--\ -------------- -------------- --------------- --------------- | ^ ^ ^ ^ ^ ^ ^ | I believe the Squirrel has terminated * Unterminated | Termination Set. -------------- -------------- | | Hard drive |-----| Hard drive |--/ * This last drive has powered -------------- -------------- termination on it. The first hard drive in the chain simply refused to work until the terminator packs had been re-installed into the drive. Whilst both CD-rom drives and the 2nd hard drive all refused to work whilst termination was present on them. As for the last hard drive, I've no way of turning the termination on or off and I don't plan on finding out because it works quite happily without me fiddling. I did have two towers before and their setups were as shown.. Tower1: Unterminated Terminated Unterminated Terminated -------------- -------------- --------------- -------------- | Hard drive |----| Controller |----| CDRom drive |----| Hard drive |--\ -------------- -------------- --------------- -------------- | | Unterminated Unterminated | -------------- -------------- | | Hard drive |----| Hard drive |--/ -------------- -------------- Tower2: Terminated Unterminated Unterminated -------------- --------------- -------------- | Controller |----| CDRom drive |----| Hard drive |--\ -------------- --------------- -------------- | | Unterminated Unterminated | -------------- -------------- | | Hard drive |----| Hard drive |--/ -------------- -------------- I'll leave you to decide which is true of SCSI Termination: the Standard (ends only termination) or the Black Art Method. IF IT WORKS, DON'T FIX IT! Not Building Cables: ~~~~~~~~~~~~~~~~~~~~ I'm not going to tell how to build a cable for this project, but I can show you the connector types, and the pinouts to make up a 25 way to 50 way connector. SCSI ribbons have 50 wires. Wire 1 is the cable marked with a secondary colour such as a red or blue stripe down the side. Be careful not to purchase security ribbon as this isn't flexible enough to be used. D type 25 pin connector _____________________________ 13 \ o o o o o o o o o o o o o / 1 25 \ o o o o o o o o o o o o / 14 ~~~~~~~~~~~~~~~~~~~~~~~~~ This D type connector was used by Apple, but seems to be taken on as a standard for external connectors for SCSI expansion. Internal IDC 50 pin SCSI connector ------------------------~~~-------------------------- 49 | o o o o o o o o o o o o o o o o o o o o o o o o o | 1 50 | o o o o o o o o o o o o o o o o o o o o o o o o o | 2 ----------------------------------------------------- All odd pins are on one row, all the even are on the other. Making up a ribbon cable using these header blocks allows you to set the connectors to exactly the correct spacing you need. Sadly, adding one of these connectors without the proper tools can leave you suffering from ripped cables, bad connections, and a lot of headaches when it comes to booting up. I've only managed to get 2 out of 7 connected correctly, and I still have some suspicions about them. Centronics 50 pin connector _________________________________ 1 \ / 25 This connector is roughly the \ +++++++++++++++++++++++++ / same size in length as the 50 26 \___________________________/ 50 internal 50 pin connector. Not Making That Cable: ~~~~~~~~~~~~~~~~~~~~~~ Most SCSI drives connect via the IDC 50 pin connector, unless the drive has higher specifications such as SCSI WIDE, DIFFERENTIAL etc, but the ones that use the IDC connector all stick to the pin assignments listed below. You may notice that none of the odd numbered pins are mentioned on the 50 way side. That's due to them all being GROUNDs and have no need to be connected. The pin-out below shows you which wires to connect to which pin, to allow you to connect it to your controller. 25 to 25 to 50 1 - 1 - 48 2 - 2 - 42 3 - 3 - 50 4 - 4 - 40 5 - 5 - 38 6 - 6 - 36 7 - 7 - GROUND (20, 22, 24, 28, 30, 34) 8 - 8 - 2 -- 9 - 9 - GROUND (20, 22, 24, 28, 30, 34) 10 - 10 - 8 -- 11 - 11 - 12 12 - 12 - 14 13 - 13 - 16 14 - 14 - GROUND (20, 22, 24, 28, 30, 34) 15 - 15 - 46 -- 16 - 16 - GROUND (20, 22, 24, 28, 30, 34) 17 - 17 - 32 -- 18 - 18 - GROUND (20, 22, 24, 28, 30, 34) 19 - 19 - 44 -- 20 - 20 - 18 21 - 21 - 4 22 - 22 - 6 23 - 23 - 10 24 - 24 - GROUND (20, 22, 24, 28, 30, 34) 25 - 25 - NOT USED (26) * -- * note: Pin 26 is labelled either TERMPWR or N/C (Not Connected) in my manual. I have connected this, and have suffered no problems (yet!). I suggest that you should connect this, as one of the drives you fit may need Terminator power and you may experience problems getting your drive(s) to work if not. Drives without powered termination wont be affected by this being connected. Installing a DF1: ~~~~~~~~~~~~~~~~~ I'm not going to start telling you how to technically connect up a floppy drive to work as DF1: You can work that out for yourselves by examining the pin assignments listed below. These are listed in the A500 user manual in the `Technical Reference' section. If you have an external floppy drive and would like to install that into the tower then read on. Oh yes, before I forget, you will have to make up a connecting cable to act as an extension between the drive's old cable and the computer. This uses 2 x 23 (twenty-three) pin connectors (1 x male, 1 x female), 25 core cable and 2 x D type socket enclosures (sheaths). Solder the pins straight through... (or get someone to make it up for you) 1 --- 1 13 --- 13 2 --- 2 14 --- 14 D type 23 pin connector 3 --- 3 15 --- 15 ___________________________ 4 --- 4 16 --- 16 12 \ o o o o o o o o o o o o / 1 5 --- 5 17 --- 17 23 \ o o o o o o o o o o o / 13 6 --- 6 18 --- 18 ~~~~~~~~~~~~~~~~~~~~~~~ 7 --- 7 19 --- 19 8 --- 8 20 --- 20 Floppy drive power connector 9 --- 9 21 --- 21 _________ 10 --- 10 22 --- 22 / o o o o \ 11 --- 11 23 --- 23 /-----------\ 12 --- 12 You'll have to open the casing on the drive, and this is usually a plastic or metal casing (can't be much else :)) and they'll either fasten together with 4 screws (metal) or simply snap together (plastic). Once you get the casing open you should see a small circuit board at the back which allows detection of other drives, and thus gives DF2: DF3: etc depending on how many external drives you have. This will be connected between the cable and the floppy drive. Be careful handling this. Unscrew the drive from the casing and DON'T lose the screws for you'll use these to fasten the drive into the tower. Dismantle the plastic casing on the connector which connects the drive to the computer, and attach this to an opening on the back of the PC case. It will probably have a plate spot-welded in 2 places covering the gap: this is easily removed. Connect the old connector to the metalwork, and install the drive, remembering to remove the blanking plate at the front first. If you want to power the drive directly from the PC case PSU then you'll have to either desolder the old power connector from the circuit board (e.g. Cumana 354) or snip it off. Otherwise simply leave it on and power the drive from the computer. With the cables connected switch on, and DF1: should be visible to the system. Don't panic if you don't at first see an icon, you may not have a floppy disk in the drive. Pin Assignments for the external floppy disk connector. 1 - Disk Ready 13 - Select disk Side 2 - Disk Ready Data 14 - Disk Write Protected 3 - Ground 15 - Drive head over Track 0 4 - Ground 16 - Disk Write Enabled 5 - Ground 17 - Disk Write Data 6 - Ground 18 - Step the Head 7 - Ground 19 - Head direction 8 - Disk Motor Control 20 - Select Drive 3 9 - Select Drive 2 21 - Select Drive 1 10 - Disk Reset 22 - Disk Index Pulse 11 - Disk removed from Drive 23 - +12 Volt DC Supply 12 - +5 Volt DC Supply Mega Wattage: ~~~~~~~~~~~~~ Ok.. you want to power you A500/+, A600, A1200 from the psu that comes with the PC case, and this is simple - IF YOU KNOW WHAT YOUR LOOKING FOR, YOU KNOW HOW TO SOLDER, HOW TO USE A MULTI-TESTMETER, AND CAN AFFORD TO BLOW UP YOUR COMPUTER IF YOU GET IT WRONG. Want to carry on? Then read on. Before starting, unplug the Amiga's PSU from the computer and switch it on. Using the multi-meter test each of the pins for voltages and write them down on PAPER! 1. Open up the PSU from the PC Case. Check that it supplies -12v (I have been told that some psu's don't) 1a. Remove the Amiga's PSU from it's plastic casing. 2. Desolder the Amiga's power cable from the circuit board. 3. Locate the 2 power connectors which supply a PC motherboard with its power. They're 2 connectors with 6 wires on each: desolder these. 4. Now Solder the respective power wires of the Amiga's cable to the PSU board. 5. Before reassembling, check that the voltages are correct. 6. Reassemble, PRAY, switch on, pray again! What! You don't have the pin-outs for the Amiga's PSU? Oh ok! This diagram is a direct copy from the casing which houses the PSU for the A500/+. I have sat on the table next to the A1200 (powered by the tower I use) which I've used to type this on. ______ ______ | \/ | 1 = +12 volt (Brown Wire) | o 1 2 o | 2 = 0 volt (Black Wire) | | 3 = -12 volt (White Wire) | 3 o | 4 = Shield (Yellow Wire) | | 5 = +5 volt (Red Wire) | o 4 5 o | | | ~~~~~~~~~~~~ For this Part I got a friend to do the work, and he knew exactly what he was doing, why he was doing it, and how to do it: and I had complete faith in him. I'll repeat myself here and say - IF YOU HAVE THE SLIGHTEST UNCERTAINTY ABOUT THIS, FIND SOMEONE WHO KNOWS EXACTLY WHAT HE'S DOING AND GET THEM TO DO IT! Getting In Touch: ~~~~~~~~~~~~~~~~~ This is an update to the original SCSITower.txt, which I got several requests for help from: and I tried my best to help them, and I believe I was quite successful in all cases. If you would like help with any of the above, please include as much information as possible, as it can take several weeks getting mail backwards and forwards, and I don't login every day to check my mail. So the more info, the quicker I can possibly help! Remember to include: Which - Computer you've got - SCSI Controller What - drives your using (and sizes) - your trying to do - you did do - connections you've made And.. Exactly what the problem is and what you've done to try and cure it.. I'm sure there are SCSI experts out there who are screaming in agony over my methods of SCSI TERMINATION. And there'll be the odd one or two who'll say I'm talking rubbish. All I'll say is if you don't like it, don't read it! If you want to send me any advice or info, I'll be glad to read and learn from your wisdom. If you have to send me abuse, I can quite happily delete those messages faster than you can write them. Here's my contact address.. Anthony Keeley (My name, just in case you'd like to use it) Snoopy@mail.on-line.co.uk (my email address, if you hadn't guessed) I look into my mailbox occasionally, so you should get an answer within a week depending on how difficult it is to answer and how much info you provided. Anthony...