gilgalad@caen.engin.umich.edu (Ralph Seguin) (03/23/91)
Hi. I have a 3.5" hard drive (Miniscribe) that I want to mount internally in my Amiga 1000. I have been told that the 1000 power supply is hefty. The question is: Is the Amiga 1000 power supply strong enough to power a 3.5" hard drive, an external floppy, an internal floppy, a RAM expansion and possibly the multi port hack? More importantly, what are the lines on the main cable going to the motherboard? Please give voltage, amperage, color (or some other method by which I can tell what is what :) and orientation. Thanks, Ralph Ralph Seguin gilgalad@caen.engin.umich.edu 536 South Forest Apt. #915 gilgalad@zip.eecs.umich.edu Ann Arbor, MI 48104 (313) 662-4805
<LEEK@QUCDN.QueensU.CA> (03/25/91)
In article <1991Mar23.022006.22851@engin.umich.edu>, gilgalad@caen.engin.umich.edu (Ralph Seguin) says: > >Hi. I have a 3.5" hard drive (Miniscribe) that I want to mount internally >in my Amiga 1000. I have been told that the 1000 power supply is hefty. You can get about 5-6A on the +5V and about 1A (1.5A peak) on the +12V supply. It is generated by a 7812 regulator chip (which sets the limit) >The question is: Is the Amiga 1000 power supply strong enough to power >a 3.5" hard drive, an external floppy, an internal floppy, a RAM expansion >and possibly the multi port hack? Yes. The +12V supply is the limiting factor here. If you make sure that your hard drive and the Amiga motherboard are the only 2 that uses the 12V supply. Typical floppy drives uses 12V @150mA. If you were to use Sony drives or other makes that doesn't require the 12V supply, you save yourself 300mA on the power budget. I am running a Miniscribe 8450 (3.5" 40Meg RLL) as internal hard drive, OMTI 5527 hard drive controller (Palomax), Lucas/Frances 020 + 4meg memory expansion for 2 years on the 1000 power supply with no major problems. There is a little bit of undervoltage (can be seen as minor ripples/distortions on screen) during the initial hard drive startup (can take 1.5A- 2A on the 12V supply) which is about 2-3 sec long and about 1-2 seconds from power is turned on (probably doing some onboard diagonistics and making sure power is stable. Thanks the designer for that. Otherwise it is very hard for the power supply. :) Once the motor started up, the current drops to about 1A or so which is very closed to the operating limit. That's why you should make sure that it is the only thing on thje 12V bus. > >More importantly, what are the lines on the main cable going to the >motherboard? Please give voltage, amperage, color (or some other method >by which I can tell what is what :) and orientation. Since you said that you want to mount it internally, you can get power for it using the power connector for the internal floppy drive. You have to change the connector, but the +5V, GND and +12V required for the hard drive is all there. Colour ? Can't remember. Use a multimeter if in doubt. The actual power requirement depends on your hard drive. Consult the data sheets or the sticker on the drive if in doubt. I know my new Quantum 105S uses less power than my 8450. :) Now if only I can design a fast SCSI interface for it that fits inside the 1000... > > Thanks, Ralph > >Ralph Seguin gilgalad@caen.engin.umich.edu >536 South Forest Apt. #915 gilgalad@zip.eecs.umich.edu >Ann Arbor, MI 48104 (313) 662-4805 K. C. Lee Elec. Eng. Grad. Student Power Option (Translated to: I am still in school, no even in my speciality and I have no money. Do it at you own risk. ) Good luck !!