Oh Sorry, I think I just confused the issue -- I ONLY get a vertical line when I use the flyback transformer connected to the OTHER Mac (put them back-to-back and used the other Mac's flyback to power the 128k's CRT, both Mac's powered on at the same time), i.e. I have disconnected the 128k's flyback -- taken it out of circuit -- and if I understand your schematic, without the flyback in-circuit, there's no HV as the flyback takes its voltage from pin-1 via the Q3 transistor and routes it to the rest of the HV circuitry? Correct? (I did this when I originally tested the flyback on the 128k to see if that was the problem -- I now know that the flyback is perfectly fine after transplanting it to the other Mac, but on the 128k it gets NO power, so the problem is before the flyback on the 128k -- there might be a problem after too, but I tested everything you mention and everything checks out, I even transplanted the nonpolar electrolytic cap to the other Mac and it worked fine. So FORGET that the I ever got a horizontal line, the flyback transformer is definitely NOT getting power from the Q3 transistor which also checks out on the other Mac, so it has to be before the Q3 which isn't getting power either. Without any outside influence, I get no picture whatsoever. Thanks!
> From: Tom Lee <[EMAIL PROTECTED]> >> good Mac's CRT. The reverse IS true, to a point -- with the 128k's >> flyback out of circuit, there is nothing to power the Horizontal >> circuit that comes after, so I get a Vertical line, but the CRT > > > Hold everything! You're barking up the wrong tree. If you are able to > see a vertical line, then the high voltage circuitry is working (and the > crt is getting the right voltages, more or less). And if the HV > circuitry is working, then the horizontal drive is working, so save > yourself the trouble of going component-by-component back to the horiz > input. > > You have a horizontal deflection problem. Here are some possible causes, > in no particular order: > > 1) Bad solder joint(s) on the analog board, where the 4-pin yoke > connector is attached. Even if you can't see a problem, resolder *with > fresh solder* anyway. This is the *most* common cause of your problem. > 2) Corroded/burned pins within the 4-pin connector. > 3) Open 3.9uF (4.7uF in some macs) nonpolar electrolytic cap (the one > often held down by a mess of hot glue). This is a *very* common cause of > the symptom you are seeing. > 4) Loose connections in the vicinity of that nonpolar cap (esp. of the > width adjustment inductor). > 5) Defective deflection yoke (possible, but I have *never* seen this on > a 9" mac) > > Again, if you can see the crt display anything (especially if it's > bright and in reasonable focus), then the HV circuitry is just fine, > because it needs horizontal drive to generate HV. Deflection is a > separate thing. > -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[email protected]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com ---------------------------------------------------------------
