Hey guys, just ran into this link that might have some relevant info on compact mac video signals, though it's an SE. This guy interfaced the original screen and analog board with a beaglebone black (small ARM linux dev board), which involved reverse-engineering the video signal and timings.
http://www.nycresistor.com/2014/02/02/30th-anniversary-mac/ He references schematics from http://museum.dyne.org/gallery/apple/stuff/mac/andreas.kann/ - which also has a full Mac Plus logic schematic, is that different the one-pager you're talking about? From a quick look there VIDOUT doesn't appear to go through any buffer transistors, but the images are also a bit rough. I'd be more inclined to look at VSYNC (pin 5), which appears to connect to U1E pin 13 and *maybe* 6522 pin 23. Verify that from the schematic before trusting. On Sat, Feb 1, 2014 at 9:34 PM, Hardware Mack <[email protected]>wrote: > that may be! > there is that 15.667mhz oscillator on the main board. > > > hey what is in-between pin 1(VIDOUT) and VIDOUT on the BMU0, seems like > the commonly available schematic is just that one pager. > > > Charles > MacCaps.com > > > > On Feb 1, 2014, at 9:09 PM, Doug McNutt wrote: > > At 15:51 -0800 2/1/14, Tom Frikker wrote: > > Interesting... if it's not the analog board, maybe it'd be some capacitor > on the main board or something? I have no clue... > > > On Saturday, February 1, 2014 6:45:44 PM UTC-5, Notgoing Totellyou wrote: > > > yeah when he slides his plus main board in there it works fine, so its not > the analog board.. > > Also when he turns up the brightness up, the line gets brighter.. there is > nothing else on the crt other then the horizontal line on the tube. > > done the VIDOUT signal pass through a transistor on the main board, i see > that vidout does come from the BMU0 i'C > > > > There are software things that depend on an interrupt synchronized with > the vertical sweep. > > Is the clock for that generated on the mother board? If not, is it > possible that a motherboard could short out a signal needed by the analog > vertical sweep circuitry? > > > -- > > --> From the U S of A, the only socialist country that refuses to admit > it. <-- > > -- > -- > ----- > You received this message because you are a member of the Vintage Macs > group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > --- > You received this message because you are subscribed to the Google Groups > "Vintage Macs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- > -- > ----- > You received this message because you are a member of the Vintage Macs > group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > --- > You received this message because you are subscribed to the Google Groups > "Vintage Macs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
