Quote:
Originally Posted by IsthmusTV
... Are you going to do anything to the cabinet? I haven't done anything to mine except superficial cleaning.
Again, congratulations. Your friend should be very pleased.
-Clark
|
Pleased and relieved as I really want to get back to my other projects
I'm not going to touch the cabinet but the owner asked for suggestions on preserving the finish. I'm no expert on blonde finishes but I figure a quality, non-silicone furniture polish found be fine.
Quote:
Originally Posted by Kevin Kuehn
Congratulations is right. I still don't understand how those bad components would cause the reveres action you were getting on the eye tube. Suppose it was a combination of the leaky caps which caused a false alignment indication at multiple resonances. Was the alignment off a lot when you went back through it? At any rate I think we're about to the point in time that we need to start shotgunning all mica caps. Although sometimes those types of caps make for a excellent leaning experience.
|
Yes, the IF between the 1st & 2nd audio stages was off as was the discriminator. Those are the areas where I replaced three micas and several resistors.
I would call it a reverse action - more like the bias point was shifted over so that the left bar would never dip below the reference bar. Now, it swings to either side. I'll show that in detail in the next video up later today.
Quote:
Originally Posted by bigaudioal
Congrats, Bob! I just watched your YouTube video last night on this set. Nice to see that you solved the audio issues and the tuning eye reverse issue. Cannot wait to see the next video of this set functioning!  |
That video was my first attempt at alignment. I'll post another video later today showing the replaced micas and second alignment with the correct tuning eye action and sound.
Quote:
Originally Posted by Phil Nelson
Micas can go bad and I have replaced my share of them, but many more in sweep circuits (horizontal, vertical) and HV circuits. Audio circuits tend to be more forgiving, but if you find a bad one -- or two -- there, of course it has to go.
I would not advocate shotgunning micas in IF stages...
|
I agree and didn't touch the tuner. Also the micas in the video IF tested OK so I left them alone. It was tempting to replace them all, but that would require yet another alignment plus those micas get expensive! Also, there's always that risk of slipping with the soldering iron and damaging a coil or other fragile component.
I think the big culprits were the bad 10pF coupling mica cap between the 1st and 2nd audio IF stages and the two bad 1K resistors which threw the bias off the 2nd tube.