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

[Penthode]

I may not be available in the morning so here goes. The table measuring at the junction of L104 and R126 is impossible because on my diagram there is no junction.
The reason your VTVM goes off scale is because there is a DC bias of at least 10vdc there.
To adjust the traps do this:
Connect the VTVM to pin 1 of V106 and ground.
Switch the VTVM to the 5vac range. Not DC.
Next switch the HP8601a AM modulation on to 1kHz.
Adjust input RF until you see about 3 volts AC on the VTVM
Adjust the traps null at frequency specified.
Raise the RF level as necessary to keep the null at no less than 1 vac.
Repeat this for each of the trap frequencies.

[Chris K]

Originally Posted by Penthode

I may not be available in the morning so here goes. The table measuring at the junction of L104 and R126 is impossible because on my diagram there is no junction.
The reason your VTVM goes off scale is because there is a DC bias of at least 10vdc there.
To adjust the traps do this:
Connect the VTVM to pin 1 of V106 and ground.
Switch the VTVM to the 5vac range. Not DC.
Next switch the HP8601a AM modulation on to 1kHz.
Adjust input RF until you see about 3 volts AC on the VTVM
Adjust the traps null at frequency specified.
Raise the RF level as necessary to keep the null at no less than 1 vac.
Repeat this for each of the trap frequencies.

So I'm starting the trap adjustments over again. Just to confirm the procedure outlined above is after removal of V107 substituting the potentiometer I made and adjusting it to -4.5V DC at resistor R135/R136 junction?

[Chris K]

Let me describe what's going on with the very first "null" of the top slug of T-103. I have the HP 8601A set as follows. Frequency is 21.25 MHz continuous. The output is 1KHz AM modulated at 10mV. It is being fed through a 1500pf cap into pin 1 of V2. The coaxial ground lead is clamped to the chassis. The VTVM is set to AC 5V range and was zeroed prior to connection. Probe is connected to pin 1 of V106 and grounded to the chassis. The 10mV RF output is the minimum output strength that can be adjusted to 3V AC but strong enough that interference, like touching the coaxial lead, doesn't cause deflection of the VTVM needle. Tuner is between channels 2 and 13.

I've turned the upper slug in T-103 a couple of turns clockwise and counter-clockwise from the initial position is resulting in no change on the VTVM.

I've checked and rechecked the connections and they are all correct. Is the RF output voltage too low? Shouldn't I get some VTVM deflection with those slug adjustments I made?

[Chris K]

...there is another adventure I might propose and I can do it anyway even if this one goes down too many rabbit holes. I have two identical untouched chassis to this one. I might start a separate thread where I take one and do a dim bulb run up to reform the caps and with guidance from Penthode and others, do the minimum to get it working well...or at the least, as well as Penthode says his TV works on mostly original components.

[Penthode]

Because it is a trap, it is sucking energy. Try cranking up the RF level until you see and indication.

It is a good idea to get a signal indication on the VTVM before you touch anything.

[Chris K]

Not sure what's going on here but I'll tell you what I'm seeing...and hearing.
Let's be certain we are on the same page. I'm trying to do step 6 in the alignment table, the adjustment of the top of T-103. I have the VTVM connected to pin 1 of V106 and set to the 5V AC scale. I'm using my AC probe and ground lead from the VTVM. The 8601 is set for a CW of 21.25MHz. I tried what you suggested about turning up the RF gain. At 30mV through 300mV, I hear the 1KHz tone very clearly through the speaker with 100mV being the sweet spot for best undistorted tone. Anything lower than 30mV or higher than 300mV, I hear no tone through the speaker. At none of these RF output voltages can I see deflection on the VTVM of any significance when I turn the slug. What the hell is going on with this possessed thing?