Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site ucbvax.BERKELEY.EDU Path: utzoo!decvax!bellcore!petrus!sabre!zeta!epsilon!gamma!ulysses!ucbvax!info-vax From: info-vax@ucbvax.UUCP Newsgroups: mod.computers.vax Subject: Max amps in a 750 (summary) Message-ID: <8512052213.AA04108@umd-cs.UMN.uucp> Date: Thu, 5-Dec-85 17:13:47 EST Article-I.D.: umd-cs.8512052213.AA04108 Posted: Thu Dec 5 17:13:47 1985 Date-Received: Sat, 7-Dec-85 02:00:08 EST Sender: daemon@ucbvax.BERKELEY.EDU Organization: The ARPA Internet Lines: 74 Approved: info-vax@sri-kl.arpa Here's the scoop on Maximum backplane amps in a Vax 11/750. Virtually everyone agrees it is 32 amps. Unfortunately the disagreements come from Digital publications! Read on! Thanks to everyone who responded! umn-cs our link to the outside world was down for a week so I apologize if I missed anyone. -steve -------------------------------------------------------------------------------- From: Alan Wu DEC Systems + Options catalog says 11/750 Unibus has 32 amps at 5 volts. This limit is easy to reach with some power-hungry options. The limit can be "stretched" a bit, but at the expense of reliability (data integrity and system integrity) and longevity (power supply is under stress). --Alan ------- -------------------------------------------------------------------------------- From: umn-cs!ihnp4!seismo!uwvax!uwslh!dem (a) On page 466 of the VAX Hardware Handbook (1982-83 edition) in appendix K It says that the power available is: 25.0 amps at +5 v 2.0 amps at +15 v 3.5 amps at -15 v However, when we were installing our vax750 I somewhere got the figure of 32.0 amps at + 5v (probably from a salesman). You probably can figure that there is some margin available over the 25 amps at plus 5 volts, but it is anyones guess how much. David Miran Wisconsin State Hygiene Lab -------------------------------------------------------------------------------- From stolaf!ihnp4!cbosgd!ucbvax!info-vax >From VAX Systems and Options Catalog page 2.2 Expansion power available in the DD11-DK (in 750 UNIBUS...GAR) is: 32.0 @+5V, 2.0 @+15V, and 3.5 @-15V. Gerard A. Robinson -------------------------------------------------------------------------------- From stolaf!ihnp4!ucbvax!info-vax The maximum amps that one DD11-DK (one nine slot backplane) can handle is 32. Check your configuration. There are limits to some devices on one unibus Brad (font of useless knowledge) Foss -------------------------------------------------------------------------------- From: Milo S. Medin (NASA ARC Code ED) 32 Amps standard. Just like a BA11 box. You could go more than that, but I would avoid it if I were you... Milo --------------------------------------------------------------------------------