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

[Chris K]

Originally Posted by old_tv_nut

On a symmetrical trace like this, how do yoiu know if it's the horizontal or vertical that's reversed?

By the frequency of the markers. It's rotated 180 degrees around the X axis...my mistake earlier

[Penthode]

The 8601a is a ramp waveform sweep to the x axis input. If the trace is backwards, there must be a phase inversion switch on the x channel input at the scope.

[Penthode]

Is that an invert button beneath the volts/div control?

[Penthode]

And can you reduce the sweep speed slightly on the generator (little knob on the lower right from panel) so that the photos show a bright clear display for us?

And I should add that on late 40's RCA TVs, almost all have the 5.1 ohm series filament resistor to the 6AL5 discriminator. I have restored about a half dozen of these sets and four of the resistors were bad or became bad shortly after coming back to life. So be prepared if you loose sound to first look to see if the 5.1 ohm is bad.

[Chris K]

Originally Posted by Penthode

And can you reduce the sweep speed slightly on the generator (little knob on the lower right from panel) so that the photos show a bright clear display for us?

And I should add that on late 40's RCA TVs, almost all have the 5.1 ohm series filament resistor to the 6AL5 discriminator. I have restored about a half dozen of these sets and four of the resistors were bad or became bad shortly after coming back to life. So be prepared if you loose sound to first look to see if the 5.1 ohm is bad.

I will check the resistor. I tried changing the sweep rate on the 8601 and took a series of photos...they were worse

[Chris K]

About as good as I can get

[Chris K]

Manipulated the photo a bit

[Penthode]

To invert the x channel so the sweep is correct from left to right, select the Vertical menu and select INV.

[Chris K]

Originally Posted by Penthode

Is that an invert button beneath the volts/div control?

It says waveform off

[jr_tech]

Originally Posted by Penthode

Is that an invert button beneath the volts/div control?

Channel invert is accessible through the menu selection button.

https://w140.com/tekwiki/wiki/TAS465
jr

[Penthode]

Originally Posted by jr_tech

Channel invert is accessible through the menu selection button.

jr

Found it in the menu. Trouble was the x channels did not require inversion but the y channel did in order to match the service notes picture.