Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!gatech!ncar!elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!uwm.edu!mixcom!oovvoo From: oovvoo@mixcom.UUCP (Mike Shawaluk) Newsgroups: comp.sys.amiga.hardware Subject: Re: 25 pin to 50 pin SCSI Message-ID: <63@mixcom.UUCP> Date: 3 Dec 90 00:12:44 GMT References: <184c8d60.ARN2546@starsoft.UUCP> Distribution: usa Organization: MIX: Milwaukee Information eXchange (Public access Usenet, Email) Lines: 90 david@starsoft.UUCP (Dave Lowrey) writes: >I recently picked up a used SCSI drive, and I want to hook it up to >my 2090A controller. >The drive bays in my 2500 are all filled, so I currently have the drive >sitting outside my amiga, with the 50 connector ribbon cable running back >inside the amiga to the controller. >I would like to do this more neatly, using the 25 pin connector on the >back of the 2090A. >Does anyone have a pinout for a 25 to 50 pin connector/cable? I have a 2091 controller, and in the back of my A2000HD manual, it gives the pinout of both the 50 pin and 25 pin connectors. From this, I can give the equivalent pin numbers for each of the connectors: Internal connector External connector Pin Name Pin --- ---- --- 50 *I/O 3 48 *REQ 1 46 *C/D 15 44 *SEL 19 42 *MSG 2 40 *RST 4 38 *ACK 5 36 *BSY 6 34 N.C. 32 *ATN 17 30 Ground 7,9,14,16,18,24 28 " 26 Terminator Pwr 25 24 Ground 22 " 20 " 18 Parity 20 16 Data 7 13 14 Data 6 12 12 Data 5 11 10 Data 4 23 8 Data 3 10 6 Data 2 22 4 Data 1 21 2 Data 0 8 Note that there are 5 "Ground" signals listed on the 50 pin side, and there are 6 ground signals on the 25 pin side, listed opposite pin 30. Also, there is the following note under the 50-pin diagram: "All odd pins, except pin 25, are ground. Pin 25 is open." I hope this helps you in making a cable. - Mike >Also, what sort of power does a hard drive require? I am curently running >it off of the amiga's power supply. I can figure out the voltages, but >how much power does a drive draw? >Another possibility would be to mount the drive to a dummy board inside >the amiga. The drive is a 3.5" drive, so it will fit. Has anyone done >this? Are there "dummy boards" avaliable? Would it need extra support, >or would the sockets and backplate screw be enough? >One other question....The 2090A has two connectors for the "hard drive" LED. >One lights the LED only for the internal ST506 drive. The other connector >lights the LED for both (all?) drives. However, when hooked to that >connector, the LED is very weak. >Is there any way to "boost" the output, so the LED is viewable when >hooked up to that connector? >If not, can I hook up the LED outputs on the SCSI drive to the LED, along >with the 2090A controller, or would that hose things up? >As you can tell, I am not exactly an EE major! Any help would be appreciated. >Thanks!!!! >---------------------------------------------------------------------------- >These words be mine. The company doesn't care, because I am the company! :-) > Dave Lowrey | david@starsoft or {uhnix1,lobster}!starsoft!david >Starbound Software Group | > Houston, TX | "Dare to be stupid!" -- Weird Al Yankovic -- - Mike Shawaluk | If you turn it over, but don't let go, oovvoo@mixcom.UUCP | you will be upside down.