Mighty Monarch of The Air

[VintagePC]

Looking at your picture, what you'd want to do is as follows. This will ensure you've tested the coils:

1. Disconnect/desolder the ground connection at the lower yellow arrow. (this ensures you test the coils themselves and not an alternate current path - note the other yellow arrow traces through the transformer and also to ground, resulting in two possible paths for the current to flow when you measure any two points in that line.)

2. Measure across the blue arrows.

3. Measure across the red arrows.

4. Reconnect the ground connection from step 1.

It looks like you have resistors in parallel with your coils in the schematic. If that's the case, the resistance you measure should be 1/measurement = 1/(coil resistance)+1/(resistor resistance). Keep in mind the coil will have a fairly low resistance, so the reading is probably only a handful of ohms.

With both resistor values the same, the red and blue measurements should be identical.

If you measure anything different than expected, you'd need to disconnect one lead of the resistor to determine the culprit (coil or resistor)

[vts1134]

Originally Posted by VintagePC

Looking at your picture, what you'd want to do is as follows. This will ensure you've tested the coils:

1. Disconnect/desolder the ground connection at the lower yellow arrow. (this ensures you test the coils themselves and not an alternate current path - note the other yellow arrow traces through the transformer and also to ground, resulting in two possible paths for the current to flow when you measure any two points in that line.)

2. Measure across the blue arrows.

3. Measure across the red arrows.

4. Reconnect the ground connection from step 1.

It looks like you have resistors in parallel with your coils in the schematic. If that's the case, the resistance you measure should be 1/measurement = 1/(coil resistance)+1/(resistor resistance). Keep in mind the coil will have a fairly low resistance, so the reading is probably only a handful of ohms.

With both resistor values the same, the red and blue measurements should be identical.

If you measure anything different than expected, you'd need to disconnect one lead of the resistor to determine the culprit (coil or resistor)

I'm good on the points you mentioned above. My problem is that I don't know where on the actual set itself is in between the two coils. It makes sense on the schematic but I can't transfer that to the set.

[VintagePC]

Hmm... it might well be an inaccessible direct connection between the coils in the yoke itself. If that's the case, the best you can do for steps 2/3 is test across the yellow arrows. the result can indicate if coils are open. It won't indicate shorts because of the parallel nature of the circuit.

The AC/variac drive test mentioned above will give better information as to the state of the coils, since you get a visible result... If it does indicate a problem in the coils, the test I described would help narrow it down.

[old_coot88]

Originally Posted by VintagePC

Hmm... it might well be an inaccessible direct connection between the coils in the yoke itself.

The connection is most always inside the yoke housing.

If that's the case, the best you can do for steps 2/3 is test across the yellow arrows. the result can indicate if coils are open.

Yep, but he's gotta disconnect one end, either the ground end as you suggested, or the top end. Doesn't matter which. While it's disconnected is a good time to also check continuity of the secondary winding of the transformer.
To the OP (original poster): is the capacitor across that winding (shown with dotted lines) actually in the set? If so, have you replaced it and/or verified that it's not shorted?
oc

[vts1134]

Originally Posted by old_coot88

Yep, but he's gotta disconnect one end, either the ground end as you suggested, or the top end. Doesn't matter which. While it's disconnected is a good time to also check continuity of the secondary winding of the transformer.
To the OP (original poster): is the capacitor across that winding (shown with dotted lines) actually in the set? If so, have you replaced it and/or verified that it's not shorted?
oc

Looking at the schematics I see that both coils are 2200 ohms. If I meter on my yellow arrows am I correct in thinking that it should be 4400 ohms?
The secondary of the transformer is good.
The third question about the capacitor across the winding in the schematics I cannot answer. I didn't see that before you mentioned it. It says that it's 75mmf, but it's not listed in the part list. Could that also be located inside the yoke housing?

[VintagePC]

Originally Posted by vts1134

Looking at the schematics I see that both coils are 2200 ohms. If I meter on my yellow arrows am I correct in thinking that it should be 4400 ohms?

Not quite - the schematics show resistors in parallel with those coils, and those resistors are each 2200 ohms. (Look at the horizontal coils - there's no resistance marking/parallel resistor).

The only time you'd read ~4400 ohms is if both coils are open.
If you read ~2200, one coil is open.
If you read something closer to zero, then the coils are probably OK (but you can't infer anything about the state of those resistors - see my parallel resistance calculation in the previous post).

BTW, if you can see those two resistors sticking out of the yoke or anywhere on the chassis, it gives you some test points for your red/blue arrows.

Originally Posted by vts1134

The third question about the capacitor across the winding in the schematics I cannot answer. I didn't see that before you mentioned it. It says that it's 75mmf, but it's not listed in the part list. Could that also be located inside the yoke housing?

It's possible, but doubtful. The easiest way to find it is to carefully trace the entirety of that vertical deflection line which your arrows point to and try to locate it. If you can't find it, you can do a test to see if it's there- disconnect BOTH ground points at each end of the line, and apply a few volts (no more than 20) AC to the line. (it will float, since it's not grounded at either end).
Then, see if some AC appears on the chassis ground. If so, that capacitor is hiding somewhere and passing AC (or it might be shorted). If not, it's probably not there.

Also, look at the connections running in to the yoke - there should be 4, two for vertical, and two for horizontal. (You may see only 3 if the lower ground is directly accessible from the yoke.
If you see more/fewer, it may indicate additional components have been hidden... try to trace them on the schematic to find out what those wires do.

[jeyurkon]

Since the 75mmf is inside of the dotted line for the deflection yoke it would seem that it is part of the yoke. Unless I'm looking at the wrong 75mmf.