phil@RICE.EDU (William LeFebvre) (12/07/85)
> 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 I suspect that either the publication was in error, or the reader was not very thorough. I don't have an 82-83 edition of the Hardware Handbook handy, so I can't scrutinize it myself. BUT, I do know that the power available on a *780* unibus is 25.0 amps at +5 V. I also know that the power available on a *750* unibus is 32.0 amps at +5 V. Two curious things about the hardware handbook. First, it is a description of all VAX hardware. Sometimes it is easy to get lost in the book and not realize that you are reading a "780 only" section instead of a general section or a "750 only" section. The other oddity is that at first, the Hardware Handbook only had to describe the 780. So it is possible that when DEC revised the book to include 750's, they forgot to clarify all the sections (like the one telling you how much power there is on a 750 unibus). William LeFebvre Department of Computer Science Rice University <phil@Rice.arpa> or, for the daring: <phil@Rice.edu>
info-vax@ucbvax.UUCP (12/14/85)
In article <1616.phil.Dione@Rice> phil@RICE.EDU (William LeFebvre) writes: >> 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 >I suspect that either the publication was in error, or the reader was >not very thorough. I don't have an 82-83 edition of the Hardware >Handbook handy, so I can't scrutinize it myself. BUT, I do know that >the power available on a *780* unibus is 25.0 amps at +5 V. I also >know that the power available on a *750* unibus is 32.0 amps at +5 V. That maybe true, but when our VAX-11/750 was delivered, there were ONLY 25.0 Amps @ +5 volts power supplies in it! When DEC was asked about this, the answer was: Well, all the new ones of VAX-11/750 is shipped with 32.0 Amps @ 5 volts. You must have got an old one. But they can be upgraded for a very little extra sum of money! We payed the price some months back, because when we had an extra disk controller in the backplane, the UDA50/RA81 started to report all sorts of hard/soft errors, due to a too big power drain. --------- Snail: Dennis Olsson, DIKU, Universitetsparken 1 - 3, DK-2200 Copenhagen N, Denmark. UUCP: ..mcvax!diku!doss +45 1 83 62 57 ext. 13.