1966 Magnavox combo issue - Page 2 - Videokarma.org TV - Video

freakaftr8 · #16 01-08-2008, 11:27 PM

Well tonight I went over my solder traces and replaced some resistors corresponding to pins 1, 2 and 3 off the oscillator tube, no change. does anyone know a quick easy way to test the mica film caps? My inductance tester sucks... And I was told that a 820pf film cap may be bad, I cannot locate it, this cap is supposed to couple the AFC

freakaftr8 · #17 01-09-2008, 11:14 AM

Hey guys, on the Oscillator board, there is this black cap, standing vertically. It is black and it's an axial type, on it it has yellow writing, it's a Sprague, .01mfd at 400v. I pulled it from the board to test it, It tests ok on my crappy ESR meter, bit I can only supply 9v to it.Anyway I reinstalled the cap, and now the set pops the breaker when I power the set up. Not right away but before the raster shows up. Now I might have put the cap in backwards. The cap has a yellow ring around the bottom. Is this cap uniderectional, or multidirectional? I feel really dumb... It was late and I probably should have just gone to bed instead.

jpdylon · #18 01-09-2008, 11:35 AM

At that rating, its probably not polarized.

Pull the horizontal output and oscillator tube and see if the breaker still pops.

freakaftr8 · #19 01-09-2008, 12:24 PM

Are the orange drops polarized?

bgadow · #20 01-09-2008, 12:30 PM

Older orange drops often had a marking to show which side should best be put to ground, but it really isn't a big deal. (old paper caps were the same way) You can install them either way. I'd replace that black cap as they aren't the most reliable. Double check your work in that area; something else might be shorting the circuit. I once put one end of a cap through the wrong hole in the PC board and it took me years and years to diagnose.

freakaftr8 · #21 01-09-2008, 03:37 PM

Ok good news!
Got te set back up and running again, was a bad solder connection from the .01mfd 600v sprague orange drop coming off pin 2 of the ocs tube. And suprisingly, the set has now been on for 20 minutes, (still on and counting) and it hasn't seemed to screw up yet! Think it might have been a bad solder joint I missed! Keepin my fingers crossed...

freakaftr8 · #22 01-10-2008, 04:26 PM

Well I ran this set for 6 hours yerterday, it started it's fluttering thing again... So i left it on! I figured screw it, im getting sick of this, let the part completely fail and then ill find it...... Well..... it did... Now the horiz is so off it shrunk the sides of the screen, If I turn the knob all the way to the left, I can see the raster, but it's far off.. Its like the phase is shifting over on the dial, the horiz lock was in the middle, now it's far off the dial, I can get it back by turning the effiency coiil, but I dont wanna do that, ill make the flyback turn into a pop tart. It used to get better if the set cooled down, not now, it's way off. Im going to replace all the film, orange drops and mica caps in the AFC circuit.. Lets see if I cant fix it..

andy · #23 01-10-2008, 04:42 PM

Sounds like the horizontal frequency is changing. The problem must be in the horizontal oscillator. If it's temperature sensitive, try applying hot air when it's cold, or freeze spray when it's hot and acting up. It's probably a cap, or resistor that's changing value with temperature. This would explain why you can't find anything when testing components while the set is off.

freakaftr8 · #24 01-10-2008, 05:48 PM

It doesnt seem to be temerature sensitive.. I tried freeze spray and heat, neither seem to change anything. But ill keep plunking away,

freakaftr8 · #25 01-11-2008, 10:18 AM

Does anyone have a schematic on this chassis I could purchase a copy from them? U9109BB build date 8/1966

Thanks

freakaftr8 · #26 01-12-2008, 02:43 PM

Got it working!!! No more glitching! Ill tell you what I did as soon as I can figure out what I did......... Im going to swap this chassis into the remote unit I picked up...

MRX37 · #27 01-12-2008, 04:36 PM

Quote:

Originally Posted by freakaftr8

Got it working!!! No more glitching! Ill tell you what I did as soon as I can figure out what I did.........

Ha ha ha ha! The mystery fix! Had a few of those myself.

bgadow · #28 01-12-2008, 10:30 PM

I went looking for the Sams. The closest I came up with is chassis U908-01-00. A ton of models come back to that same Sams folder. If you need it let me know.

Bill R · #29 01-12-2008, 10:57 PM

Set 887 floder 2. I think his is a U911/919/920 series. I don't think the 908 uses the same crt. That's what I came up with from the original thread.

Bill R.

freakaftr8 · #30 01-13-2008, 04:46 PM

Cool thanks guys, looks like it's working great now, the only issue in that the horiz width is stretched a little and the horiz pincushion is out. Does anyone know wwhat controls this?