I think my flyback transformer has finally failed. The CRT is now blacking-out and refreshing the solder joints at P1 and the transformer has not helped. A classic Mac repair guide by Tom Lee indicates the flyback transformer was a poor design choice and I am wondering if anyone knows if there are more robust alternatives. Finding a new flyback is proving to be difficult. Would later model Mac flybacks work such as the ones for the Classic or Classic II? Does anyone have a known good analog board that they are interested in selling?
Thanks, tt On Tue, Nov 1, 2011 at 2:39 PM, Doug McNutt <[email protected]>wrote: > At 15:57 -0400 11/1/11, Charles E. Fox wrote: > >At 02:04 PM 01/11/2011, you wrote: > > > >>On Tue, Nov 1, 2011 at 2:34 AM, Charles E. Fox <[email protected]> wrote: > >>> -- Many years ago when I did TV repairs we used to apply stuff > called > >>> corona dope. Try Radio Shack. > >> > >>Interesting suggestion. I did a little more searching and read that > >>sometimes flyback transformers can crack from overheating or aging. > >>If the internal high voltage is creating a corona/plasma since it is > >>exposed to air, does it mean that my transformer is still OK? I am > >>guessing if there was internal shorting, that the part would already > >>have gone bad. Does the corona dope need to seep into the transformer > >>to fill voids or do I just need to seal the cracked surface of the > >>transformer? > >> > >>Thanks, > >>tt > >> > >>-- I haven't had occasion to use this stuff in fifty years, but don't > think you will harm anything by applying it in the area where the corona is > visable and letting it dry before powering up. > >> > > Neat pictures. It really helps to open the dark one in something that > allows you to play with colors and contrast. But I don't have any answers > and it's not a cracked solder joint. > > Those coils, inside, are probably would with metal foil that looks a lot > like the aluminum sticky tape that comes in a roll. It's conceivable that > one turn is sparling to its neighbor and somehow the light is getting piped > to the top where it gets out. But through the opaque plastic covering? > > The red paste looks like GE Glyptal, a paint like product that is found in > laboratories and used for the likes of repairing small vacuum leaks and > high voltage insulation. I wouldn't expect to find it on a new flyback coil > especially in a hand painted blob. Someone else may have been bothered by > the sparks. > > I'm staring at an SE analog board from which I have stolen parts. Flyback > in a case like the picture 157-0042A TAI-HO Taiwan 08730 visible on the > coil near C13. Colorado Springs. CO USA 80919. Want to try it out? I > seriously doubt that I'll ever get around to using it. > > > -- > > --> 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 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/
