Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!njin!spcvxb.spc.edu!terry
From: terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr.)
Newsgroups: comp.sys.dec
Subject: Re: Second RD54 in MVII
Message-ID: <1990Dec30.091947.928@spcvxb.spc.edu>
Date: 30 Dec 90 09:19:46 GMT
References: <451@nwnexus.WA.COM>
Organization: St. Peter's College, US
Lines: 34

In article <451@nwnexus.WA.COM>, craig@nwnexus.WA.COM (Craig Suhadolnik) writes:
> The solution to running a second RD54 in a MVII, concerning write   
> protection etc, is to find the alternative style control panel
> to add to your BA23 box.  These panels are included on some MVII BA23      
> boxes, and on some MicroPDP BA23 boxes.  The panel has a second write
> protect switch for the second disk.  The cabling is the same, and the
> panel is easy to install.

  This is available from DECdirect +1-800-DIGITAL as part number BA23-UC.

> I did this once when I configured a MVII in a BA23 without a TK50, 
> the second RD54 resided in the TK50 bay.

  Be very careful doing this. The BA23 power supply only delivers 7 amps
of +12 (6 if it's an older model). Two full-height disk drives in a BA23
_will_ exceed the capability of the power supply.

  I've found that either running an external power supply cable for the
second drive, or extending the second drive's data cables out to an ex-
ternal box, works just fine. Of course, to have a "supported" configur-
ation with two full-height drives, DEC wants you to have an RQDXE exten-
der card and a RD5x-DA external mounting box. However, as we're a self-
maintenance shop, support issues are of little concern to us.

  Lastly, even with just a single full-height drive, you may have a prob-
lem, since there was an FCO to the BA23 (and BA123) wiring harnesses. The
older ones tended to burn up and cause very nasty failures. The correct
harness has white connectors and individual wires. If your harness has 
yellow connectors, or the cable is webbed ribbon style, contact your Field
Service provider to get the FCO installed.

	Terry Kennedy		Operations Manager, Academic Computing
	terry@spcvxa.bitnet	St. Peter's College, US
	terry@spcvxa.spc.edu	(201) 915-9381