What signal is sent from the main board to the analog board on these units? I was going to guess the same a Tom, that the vertical sweep circuits are gone wacky... that only seems to make sense in this case if that signal is generated on the main board.
On Sat, Feb 1, 2014 at 6:51 PM, Tom Frikker <[email protected]> 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 >> >> >> Charles >> MacCaps.com >> >> >> >> On Feb 1, 2014, at 6:32 PM, Tom Frikker wrote: >> >> I think your vertical sweep is broken. A possible fix is to resolder the >> joints of connector P1. If this doesn't work, let me know and I'll keep >> looking for clues. >> Tom >> >> On Saturday, February 1, 2014 6:21:04 PM UTC-5, jWs wrote: >>> >>> >>> Have him turn up the brightness to see if it's scanning the full screen. >>> >>> If it's not, then the prob is still on the A/B board. >>> >>> - JS >>> >>> On 2/1/14 6:00 PM, Tom Frikker wrote: >>> >>> Hi Charles, >>> It sounds to me like the component that "stretches" the video vertically >>> has failed, and therefore, it's just a horizontal line in the center of the >>> screen. Does this sound correct? I'm pretty sure that maybe electromagnets? >>> do the "stretching", so maybe something that powers the vertical ones >>> failed. Sorry for the bad terminology, but this might be something to look >>> into. >>> Tom >>> >>> On Saturday, February 1, 2014 5:10:06 PM UTC-5, Notgoing Totellyou >>> wrote: >>>> >>>> I re-capped my buddys A/B, really all it needed was C1, pretty typical >>>> ... >>>> >>>> I changed those caps, sent it back, didn't bother to test it because >>>> he said it still sorta worked. >>>> >>>> Anyways. he got it back, and now when he flips it on, hears the >>>> bong, but on the screen all he has is a horizontal line. >>>> I think it even boots from a disk too! >>>> >>>> Anyways i told him to try his plus main board, just to make sure >>>> something funny didn't happen with the A/B i re-capped for him. >>>> and sure enough the plus main board works fine with the A/B , so the >>>> Issue is not the A/B. >>>> >>>> He said that when he removed the A/B originally, to send it to me, He >>>> used an alligator jumper and connected it to the screwdriver and the case, >>>> and not to the ground lug at the top of the screen, >>>> said it made a pretty good pop too. >>>> They make sure to say, on most of those apple sites. connect to the >>>> ground to the ground lug. >>>> >>>> >>>> So i my question is, What do you think went out on his main board? >>>> he is probably going to send it to me to fix, I don't mind.. ill help >>>> em out. >>>> But just not sure where to start looking. >>>> >>>> let me know if you have any pointers. >>>> >>>> maybe i will get him to send you something out for helping me fix it >>>> :) >>>> >>>> Thanks >>>> Charles >>>> >>>> >>>> >>>> I am looking at the schematic here. >>>> either i am getting older or this one just looks blurry. >>>> http://www.digibarn.com/collections/diagrams/mac- >>>> 512klogicboard/mac-logic-schematic.jpg >>>> >>>> >>>> -- >>> -- >>> ----- >>> 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. > -- -- ----- You received this message because you are a member of the Vintage Macs group. 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