Xref: utzoo comp.sys.m6809:1480 comp.sys.tandy:3276 Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!batcomputer!cornell!rochester!pt.cs.cmu.edu!o.gp.cs.cmu.edu!andrew.cmu.edu!ww0n+ From: ww0n+@andrew.cmu.edu (Walter Lloyd Wimer III) Newsgroups: comp.sys.m6809,comp.sys.tandy Subject: Re: Color Computer 1/2 + Disk Drive Message-ID: Date: 21 May 91 16:12:24 GMT References: <2819@lee.SEAS.UCLA.EDU> Distribution: usa Organization: Network Development, Carnegie Mellon, Pittsburgh, PA Lines: 29 In-Reply-To: <2819@lee.SEAS.UCLA.EDU> Your disk controller is probably one of the older Tandy models which required +12v in addition to +5v. The CoCo 1 supplied +12v but the CoCo 2 and 3 do not. You need to do one of the following: 1.) Get a Multipak Interface (I think all the Tandy models supply +12v, but I'm not entirely sure). Multipaks are rather difficult to find. You might find a used one for sale, or maybe a third-party version (make sure it supplies the +12v). 2.) Get a newer disk controller which does not require +12v. 3.) Hack your drive and controller to get the +12v from the drive power supply. This is what I did in order to run my old controller in my CoCo 3; it worked fine. Make sure you tap off the regulated side of the power supply. You also have to turn on the drive first, then the computer (the WD1793 disk controller chip requires the +12v to come up either before or at the same time as +5v). 4.) Hack your CoCo 2 to supply +12v. 5.) Use some kind of external +12v power supply. This and (4) are pretty similar since you'll probably need many of the same components (transformer, rectifiers, filter capacitors, voltage regulator). Good luck, Walt Wimer