Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!orca!javelin.sim.es.com!blgardne From: blgardne@javelin.sim.es.com (Blaine Gardner) Newsgroups: comp.sys.amiga.hardware Subject: Re: power supply bad? Message-ID: <1991Apr27.153822.27398@javelin.sim.es.com> Date: 27 Apr 91 15:38:22 GMT References: <1991Apr27.043711.15468@sbcs.sunysb.edu> <1991Apr27.050724.18127@sbcs.sunysb.edu> Reply-To: blgardne@javelin.sim.es.com Organization: Evans & Sutherland Computer Corporation Lines: 72 dtiberio@eeserv1.ic.sunysb.edu (David Tiberio) writes: >In article <1991Apr27.043711.15468@sbcs.sunysb.edu> dtiberio@eeserv1.ic.sunysb.edu (David Tiberio) writes: >> I have to make this quick... Ok, but don't make it so quick that we don't have any information to work with. >> My hard disk (3 days old) is spinning constantly. LED comes on only when >>accessed (as it should). It heatsup very quickly, along with 68000 and >>the power supply. I never heard my hard disk make a noise until 10 minutes >>ago. Coulkd it be the power supply isn't strong enough? What computer, what additional hardware, what power supply? > 6) I have a Baseboard ram expander with two megs on it, for a grand total > of 2.5 megs ram. > 10) Power for the hard drive is from the power I used to use for df0:. > 11) It is a TEAC SD-340 IDE hard drive, using AdIDE 40 hard drive controller, > in an Amiga 500. Ok, now we're getting somewhere. Let's see if I've got everything. You have: An A500 A 2.5 megabyte internal RAM expansion An internal hard drive and controller One (?) floppy drive No (?) other expansion devices attached to the A500 The stock (?) power supply Anything I missed? If I have this even close to right, you DO have a power supply problem, and are close to damaging a lot of expensive hardware. Shut everything off, and LEAVE IT OFF, until you can test all the voltages with a multimeter, or have someone do it for you. The problem (assuming you've got the stock power supply) is that you've exceeded the capacity of the power supply by a huge margin. The stock A500 supply will only run 2 floppies, and a total of 1M of RAM (512K on the motherboard + the A501). This configuration leaves you only 300 mA of +5V and 50 mA of +12V available for expansion devices. Any expansion device other than a ROM cartridge REQUIRES its own power supply. Both RAM and hard drives are power hogs, running one alone pushes the power supply over its specs, running both is a guaranteed failure. There are two ways to fix your problem. First, buy a huge (200 watt or so) power supply and replace the stock supply. That will get things working most likely, but you will still be drawing high currents through the motherboard to power the RAM and HD. The motherboard was not designed for this, so you may have long-term reliability problems. Second, supply power to each individual expansion device. This will avoid heavy loads on the motherboard power buses, but may be impossible due to the design of the expansion devices. Good luck with it. Soapbox mode on: Personally I think that any hardware vendor that sells unpowered expansion devices for the A500 should have IC legs pushed under their fingernails, followed by a shot of flux stripper. Soapbox mode off: -- Blaine Gardner @ Evans & Sutherland 580 Arapeen Drive, SLC, Utah 84108 blgardne@javelin.sim.es.com BIX: blaine_g DoD #46 My other motorcycle is a Quadracer. FJ1200