I've been doing some troubleshooting with a few aspects of my 1404A and am confused about something regarding the power rails. Various schematics reference +15V (some have a +15V(A) and +15V(B) designations); however, I'm not finding where those are sourced.
The mainframe supplies various voltages to the two plugin jacks but those don't include 15V. I think there may be a regulator of sorts on the an A13 board but, so far, I have not found that schematic. Furthermore, Paragraph 8-21 Section d states there is supposed to be various voltages present on the A13 board as well as a "VR1" that provides +15Vdc but I have not found that regulator. Figure 8-28 shows an image of the A13 board (which, like the rest of the scanned images, is very poor) but I can't find a schematic.
Is the A13 schematic missing from the online PDFs? Is there another board that contains VR1 and, for that matter, a better scan of the manual somewhere?
Thanks,
Barry - N4BUQ
