Ok. Let’s try this again…RCA 9TC240 Alignment

[Penthode]

I concur. The shunting of the coils with the 330 ohm resistors will mean the gain is reduced. You may try reducing the bias a tad with the rheostat. Also you may need to raise the signal a bit.

You want to ensure the curve does not appreciably change with signal level and bias change. That you can verify raising a lowering the signal a bit.

[Chris K]

Ok thanks for the input. Can someone please check me I have the shunting resistors correctly connected? It says to shunt the primary coil of each of the four. Am I correct that the primary coils are the ones in circuit and the secondary coils are stand alone?

[Penthode]

There are no secondaries. What you are calling the secondaries are the traps. The stages are capacitively coupled not transformer coupled except for the link between the mixer and 1st Video IF stage.

You are shunting each of the coils.

Do you understand why you are shunting the coils with the resistors?

[Chris K]

Originally Posted by Penthode

There are no secondaries. What you are calling the secondaries are the traps. The stages are capacitively coupled not transformer coupled except for the link between the mixer and 1st Video IF stage.

You are shunting each of the coils.

Do you understand why you are shunting the coils with the resistors?

No you have lost me. I guess transformer is the wrong term. I don't know what "capacitively coupled" means. I think the purpose of the traps was discussed before and at one point I had the concept but now I'm not sure. I think I remember they were to "trap" and eliminate certain frequencies from the video signal minimizing interference but the only one I recall being discussed was T-103 and the 21.25MHz trap.
There are a lot of terms I listen to without completely understanding them. I know the standard definition in everyday life of the word "coupled" but in electronics I'm not so sure. Most of what has been talked about leads me to think when 2 things are "coupled", one affects the other despite not being directly connected. Is this correct? Capacitively coupled??? Nope. Loosely coupled??? Nope

[Chris K]

Originally Posted by Penthode

There are no secondaries. What you are calling the secondaries are the traps. The stages are capacitively coupled not transformer coupled except for the link between the mixer and 1st Video IF stage.

You are shunting each of the coils.

Do you understand why you are shunting the coils with the resistors?

When the instructions say "shunt the primaries" I just assumed there were secondaries

[Penthode]

Originally Posted by Chris K

When the instructions say "shunt the primaries" I just assumed there were secondaries

Funny. I went back and looked at the instructions and it calls the units transformers and calls the coils "prim." implying primary. Semantics.

The main issue is the coils are stagger tuned to cumulatively provide the wide bandwidth required. The shunting of the coils with the 330 ohm resistors is to effectively remove each tuned IF stage so that the response will be governed only by the tuner to 1st IF over coupled transformer link.

[old_tv_nut]

"Coupled" simply means "connected." The means of connection can be a transformer or a capacitor, or less commonly, a resistor or inductor.

[Chris K]

Originally Posted by Penthode

Funny. I went back and looked at the instructions and it calls the units transformers and calls the coils "prim." implying primary. Semantics.

The main issue is the coils are stagger tuned to cumulatively provide the wide bandwidth required. The shunting of the coils with the 330 ohm resistors is to effectively remove each tuned IF stage so that the response will be governed only by the tuner to 1st IF over coupled transformer link.

In the schematic, what do the twin up and twin down arrow designations next to the coils mean?

[Yamamaya42]

Originally Posted by Chris K

In the schematic, what do the twin up and twin down arrow designations next to the coils mean?

I assume that's to denote an adjustable core type coil on the schematic.

[old_tv_nut]

Could the arrow directions indicate the top core and bottom core? Not sure.

[Yamamaya42]

Or, perhaps it means coils that can be adjusted from both the top or bottom of the chassis? I am seeing the same thing on color set schematics, that i know have one core, but when i look at the convergence board that can only be done from above, it has a one way arrow

[Chris K]

I thought adjustable had a diagonal through it. I’ve looked in a dozen schematic symbol lists and I can’t find a thing

[Penthode]

There is no real standardization. But in RCA lingo from other equipment, the parallel lines means a ferrite core and the arrows point to where it is to be adjusted.

[Chris K]

So what tabs on these things am I shunting with the resistors? I haven’t gotten a clear answer for that. I listed the setup and posted the schematic previously but I didn’t get any information. Is it the up arrow side of the coils being called the primaries?

[Penthode]

Originally Posted by Chris K

So what tabs on these things am I shunting with the resistors? I haven’t gotten a clear answer for that. I listed the setup and posted the schematic previously but I didn’t get any information. Is it the up arrow side of the coils being called the primaries?

The arrows pointing up mean the trap adjustment is on the top of the chassis. The arrows pointing downmeans the adjustment for the stagger tuned stage is made from under the chassis. Each stagger tuned stage has a resonant coil which connects to T102 terminals A/B and T103 terminals A/D, T104 terminals A/Band and T106 terminals D/C.

The resistors are placed across each stagger tuned coil. There is really no primary and I don't know why you are hung up on that. There is the stagger tuned coil and the parallel tuned trap mutually coupled to it. It is clearly identified on the schematic.

Do you understand what you are doing by clipping in place the resistors? It is to eliminate the resonance of the stagger tuned coils so that the remainder of the video IF strip is just an untuned amplifier. This is so you can see independently the tuner over coupled transformer link frequency response when you sweep it. You must try and understand the process so so will be better able to identify and rectify any problems.