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

[bandersen]

Yep. It's just a coil and cap in parallel. Traps the resonant frequency.

[Chris K]

Does it matter what side of R119 I connect the VTVM? And signal strength on the generator? Cant find that, just where to inject it

[Chris K]

I'm pretty certain this is R119 but I'm getting voltage that's pegging the VTVM when I use the suggested 3 volt scale (I'm using the 5V because my VTVM has 1.5V and 5V scale ranges). I was on the other side of the resistor than in this photo when I got that but I'm hesitant to go further. The pot is adjusted for -4.5V DC at the intersection of R135 and R136 on my DMM

[Penthode]

I see only one clip lead on the load resistor. Where is the other lead? Is that lead to the VTVM?

Read the instructions. It says you connect the VTVM ACROSS R119. The reason the meter is pegging is because you are measuring the -120vdc B supply!

Going back to the shock hazard thing again: do you understand that the case of the VTVM when you hook it's other "ground" lead to the other end of the resistor, the case of the VTVM will be at -120vdc with respect to the chassis?

[Chris K]

Wait...connect the VTVM "ACROSS" R119? Does that mean DC probe on one side of R119 and ground clip on the other side of R119?

[Penthode]

Yep, you have it. Just be careful not to touch the case of the VTVM when touching the chassis.

[Chris K]

Originally Posted by Penthode

Yep, you have it. Just be careful not to touch the case of the VTVM when touching the chassis.

Yes...got up to step 16. A couple of questions before I proceed. I may need to go back and make some changes.

Where do I set the brightness and contrast controls? As I was starting with the potentiometer adjustment, I had a bright horizontal line which I suspected so I turned the brightness down. As I got further along, the line returned even with minimal brightness. I don't want to burn the tube so I adjusted the contrast to get rid of the line. All of this changed the -4.5V setting so I tweaked that a bit but now that I'm thinking about it, the appearance and disappearance of the line is due to the frequency changes I was feeding in?

I don't know. I guess what I need to know is where to set the brightness and contrast from the beginning and what to do if I see voltage on the pot controlled monitoring spot varying from -4.5V?

[Penthode]

Just set the brightness and contrast to minimum. Ensure there is no CRT beam current. That is all.

The -4.5v is only an approximate. The important thing will be you seeing the dip on the meter as you adjust the traps for minimum.