[cctalk] [holm@freibergnet.de: Re: PSU of a 11/23SD??]

That is a BA11-M box with a H780 supply. The schematics can be found in the KC780 document since the front end processor of the 11/780 is a PDP-11/03 with a RX01 drive. In the end of this document there is a schematic: http://bitsavers.org/pdf/dec/vax/780/MP00534_KC780_Nov77.pdf Good luck! /Mattis Den mån 13 mars 2023 kl 10:57 skrev Holm Tiffe via cctalk < cctalk(a)classiccmp.org&gt;gt;: > > Hi all, > > I have to repair an PSU of a 11/23 n a BA11 Box with an H9720 Backplane > (with an KDJ-11A) that has run an CNC milling machine until 2 weeks > before now. :-) This is a Fidia machine..never heard about it before. > > The problem is that a big 19000µF 40V capacitor in the PSU has failed > and that I think because of that the 2nd of the two Nidec fans has > finally failed. > I'm in the process of cleaning the goo from the PSU-PCB, found a burnt > 5A fuse and now I'm checking the Semiconductors... > > The problem is here that the Transistors (and diodes) have uncommon > types printed on, an TO220 is named SJE2677, another one is labeled > 12652-00 RCA..and so on. > I've found a label with "0H780-B" on the PSU.. H780 PSU? > Where can I get some schematics from that beast? It is a secondary > switcher ist seems. > > Regards, > Holm > -- > Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, > Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 > info(a)tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790 > 741 > >