Zenith 10S690 Volume Control Issues

[vortalexfan]

Originally Posted by old_coot88

OK good. Now put the checker from the other side of the cap to where the signal lead exits the can. If it's got crumbly insulation, it should be easy to make contact. Or use a pin to stick thru the insulation. The checker should show continuity.

If it does, this suggests C11 is bad. Try the paralleled .0033/.0047 caps for C11.

Well I didn't get continuity at that point that you told me to check, so I guess that means the capacitor is fine?
I'll still try the .0033 and the .0047 together to see what happens there,
also I'm trying to replace the old crumbling wire coming out of the IF can with some new wire.

I also have a question about how to go about putting that small cardboard spacer back into place on the bottom of the IF coil that helps keep the IF coil centered in the IF can, because it came loose at some point in its life and when I took the can apart it fell out and it looked like it was held into place with a dollop of wax of the same varity that they used to insulate the rest of the IF coil with, is that just everyday parafin wax or did they have something added to it to make sure it didn't harden right away so that they could brush it on to the bottom of the IF can spacer?

I would like to put that spacer back on and make it look as original as possible seeing as this is such a low hours set and is such a perfect candidate for restoration.

[old_coot88]

Hey, since this is a phono/radio rig, have you cleaned the phono/radio switch with Deoxit or similar? Jeez, I shoulda thought of that before. Senior moment.

[vortalexfan]

Originally Posted by old_coot88

Hey, since this is a phono/radio rig, have you cleaned the phono/radio switch with Deoxit or similar? Jeez, I shoulda thought of that before. Senior moment.

No, I haven't, I thought about it but haven't yet, but maybe, I should of tried that first.

I still am going to fix the wire for the IF can because it had crumbling wire insulation to the point that it had exposed wire.

[old_coot88]

Now that you've isolated which side of C11 the break is at, it's 99% gotta be in the switch.

On that cardboard spacer thingy, maybe a dab of 5 minute epoxy(?).

[vortalexfan]

Originally Posted by old_coot88

Now that you've isolated which side of C11 the break is at, it's 99% gotta be in the switch.

On that cardboard spacer thingy, maybe a dab of 5 minute epoxy(?).

OK so I got the IF Can rewired and I cleaned the Radio/Phono mode switch and I put the radio back together and Its completely dead again, no reception whatsoever, and I made sure I wired the new wire in at the right spots and everything and I can't get any signal out of the radio whatsoever, not even a bit of static, the only noise it will make is the popping noise of the tone control switches being pressed and that's it.

I even tried fiddling with the phono/radio switch and its still not responding.

Any ideas as to what may have happened?

[old_coot88]

If you had the coil assembly completely out of the can to work on it, how many wires did you have to disconnect/reconnect?

[vortalexfan]

Originally Posted by old_coot88

If you had the coil assembly completely out of the can to work on it, how many wires did you have to disconnect/reconnect?

I just disconnected 2 wires and that was it, the wire that attached the IF can to the 1 Meg resistor and the grid cap wire which I had to disconnect to get the coil out of the can.

When I disconnected the grid cap lead I just went ahead and replaced the wire because the old grid cap wire was starting to disintegrate, and I tried to make sure the 2 wires connected back to where they were supposed to go by doing the wires one at a time.

So I don't know, the only thing I can think of is that maybe I accidentally disconnected one of the coil wires that went to one of the two terminals I removed the wires from.

[old_coot88]

Yikes. That's the wrong IF can if it has a grid cap lead coming out the top. It's the first IF. Probably a fine coil wire got broke.

All this while, I assumed we were talkin' about the second IF can, the one that has the detected audio lead coming out the bottom. Never assume. Lesson learned.

Edit:
If you find a broken wire in the 1st IF can, here's a handy-dandy way of stripping hair-fine wire that doesn't involve mechanical scraping. It really works. Scroll down to post# 26 - http://videokarma.org/showthread.php?t=257295&page=2

[vortalexfan]

Originally Posted by old_coot88

Yikes. That's the wrong IF can if it has a grid cap lead coming out the top. It's the first IF. Probably a fine coil wire got broke.

All this while, I assumed we were talkin' about the second IF can, the one that has the detected audio lead coming out the bottom. Never assume. Lesson learned.

Edit:
If you find a broken wire in the 1st IF can, here's a handy-dandy way of stripping hair-fine wire that doesn't involve mechanical scraping. It really works. Scroll down to post# 26 - http://videokarma.org/showthread.php?t=257295&page=2

Ah yes, asprin trick, I think I read about that on here before, but unfortunately I don't have any on me right now.

And I didn't realize you were talking about the other IF can, because the only wire lead I saw going to that area was coming from the IF can with the Grid Cap, I didn't see the wire coming from the IF can without the Grid Cap.

[Kevin Kuehn]

Originally Posted by vortalexfan

And I didn't realize you were talking about the other IF can, because the only wire lead I saw going to that area was coming from the IF can with the Grid Cap, I didn't see the wire coming from the IF can without the Grid Cap.

R11 and C2 form the AVC filtering. Take a look at the schematic and you will see that each end of R11 goes to a separate IF can.

[old_coot88]

Deleted bad info. Disregard sketch, correction shown in post# 83

[old_coot88]

Deleted bad info. Disregard sketch, correction shown in post# 83.

[vortalexfan]

Originally Posted by Kevin Kuehn

R11 and C2 form the AVC filtering. Take a look at the schematic and you will see that each end of R11 goes to a separate IF can.

OK, well it was kind of hard to see that in the actual radio chassis because of how they had it wired up.

[vortalexfan]

Originally Posted by old_coot88

When you get the newest problem fixed and ready to revisit the original problem, the open is almost certain to be in the radio/phono switch, per the attached sketch. To verify, put a jumper across it and see if the audio is restored and the vol control works correctly.

OK, well I'm kind of wondering if it isn't the radio/phono mode switch that's causing my problems because it cuts in and out when I flip between modes (when it was functioning before this latest problem occured.)

[vortalexfan]

OK well I was able to verify that the wiring in the IF can was fine, and that the problem definitely most likely lies in the Phono/Radio switch.

So now to try and figure out how to fix that issue...