The PSU (and the PDP11/73 in a BA11) is working again.
After thorough cleaning of the PSU PCB (had to dismount the heatsink and the 3 TO3's, loosen the TO220's) I'vew checked the semiconductors..ok so far. Fuse F2 was blown. Interestingly the electrolyte of that original Mallory cap seems to have some oil based blackish contents, it was impossible to remove that in a water/soap solution, even in a ultrasonic cleaner. I've finally used "white spirit" (Terpentinersatz in german)to clean up the things. I've mounted new fans (230V~ Types from EBMPABST (230V~ here anyways)) and now the pdp is working again, at least with ODT, don't have that RX02 from that machine here. Regards, Holm Mattis Lind wrote: > 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@classiccmp.org>: > > > > > 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 > > i...@tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790 > > 741 > > > > -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583 i...@tsht.de Fax +49 37292 709779 Tel +49 37292 709778 Mobil: 0172 8790 741
