On Tue, Jun 9, 2020 at 3:10 PM Bill Gunshannon via cctalk <cctalk@classiccmp.org> wrote: > > On 6/9/20 2:51 PM, Glen Slick via cctalk wrote: > > On Tue, Jun 9, 2020 at 9:04 AM Bill Gunshannon via cctalk > > <cctalk@classiccmp.org> wrote: > >> > >> I have a VXT-2000. It is broke. If I could find out what the voltage > >> and current requirements were and their positions on the power connector > >> I would replace it in a heartbeat. > >> > > > > For the VXT-2000 with an H7109-B the rated voltage and current values > > are printed right on the power supply label: > > > > +5.1V, 7.81A > > +12.1V, 0.62A > > -12.1V, 0.46A > > -9V, 0.2A > > > > Fixed width character pinout diagram: > > > > +=================+ > > -9V | Yellow | Orange | +12.1V > > +--------+--------+ > > ??? | White | Black | Gnd > > +--------+--------+ > > +5.1V | Red | Blue | -12.1V > > +--------+--------+ > > +5.1V | Red | Black | Gnd > > +--------+--------+ > > Gnd | Black | Black | Gnd > > +=================+ > > > > The mystery is the White wire. The power supply label only lists 4 > > output voltages. The White wire appears to be routed to the Ethernet > > daughter board. The measured voltage appears that it might be floating > > slightly negative, somewhere around -1.5V when the Ethernet daughter > > board is installed and around -5V when it is removed. Maybe it is a > > high impedance earth ground connection? It appears to be connected to > > the shield of the Ethernet BNC, which measures around 1M-Ohm to the > > chassis ground when the power supply is disconnected from the main > > board, and around 0.75M-Ohm when the power supply is connected. > > > > > Thank you for that. Mine has no labels or anything. It is PC Board > with Digital, Side 1, Side 2 and a number I don't recognize on it. > I guess the -9V is the only odd one but you could easily get that > from a -12V line. I may get to fix it yet. > > bill
(I was going to change the subject line for this reply to reflect the VXT-2000 discussion but maybe it is already too late to do that without making message threading even worse?) Does your VXT-2000 look significantly different than the images on this page? Is the power supply in your VXT-2000 a bare board that is not fully enclosed? https://terminals-wiki.org/wiki/index.php/DEC_VXT2000 The power supply in my VXT-2000 matches the fully enclosed H7109-B power supply as shown in this image: https://terminals-wiki.org/wiki/images/b/bb/DEC_VXT2000_111543249570-2.jpg
