Emerson 1146D Fusible Resistor

[Doug66]

Thanks for alll the input to this. I had recapped the set and negelected to replace the resistor.

[Doug66]

Ok, I had to replace the fusible resistor, rectifier, and fuse, but the set is playing again. I have one issue, and it's not one I have encountered before. There is some horizontal pulling in the picture, but it starts at the bottom of the screen, moves upwards, then repeats. I've encountered barkhausen oscillation before, but this is a horizontal line. I have replaced the damper tube and swapped the 6SN7 sync amp and horiz AFC tubes which didn't change anything.

In the pic, the issue is at the lady's head. If someone can give me an idea of the offending circuit, I can know where to start troubleshooting.

Thanks
Doug

[Findm-Keepm]

Open input filter? A bad B+ filter will give either a 60Hz or 120Hz "crawling line" in the picture. Any accompanying buzz in the sound??

It could also be AGC action, see if the AGC control has any effect.

If you have a scope, check out the B+ ripple - but be sure your set is on an isolation transformer and that your scope and probe are capable of measuring ~300V. B+ ripple is dead giveaway to an open filter/smoothing capacitor.

Cheers,

[Doug66]

First, thanks to Steve McVoy and Tom Albrecht for scanning the Sams to the ETF for me.

2nd, this is a portable AC/DC set, and it does not have an AGC control, but does have a 5U8 AGC rectifier.

I've replaced all filter capacitors. Now on the fusible resistor: it's supposed to be a 5 ohm 5W. All I had was a 10ohm 5W, but my source voltages are fine.

I don't have a scope yet. Was going to get one from a retired TV repairman, but the deal fell thru. Here are the circuits that were mentioned. I'll check voltages on the 5U8 next.

[zeno]

A line running through the pix is almost always a
bad filter cap. Usually there is also a hum. One line
is 60 hz, 2 lines are 120 hz. You need a full wave power
supply to give 2 lines.
Other thing is rare. A tube with H-K leakage.
Third thing is interference from another piece of gear.
Check your work then try "jumping" or "bridging" the
electrolytics. More on that if you need it.

73 Zeno