When is alignment required?

[UberVacTuber]

Thanks for the input. The picture quality seems pretty good, and the audio is clear. Sometimes the audio is kind of weak depending on the source, so that's why I was curious. I can get the sound to come in stronger, but then I get distortion of the picture (the picture will twitch along with spikes in the volume).

The top of the picture looks a little wavy, although most of that can be straightened out with the Horizontal Hold. There is also a bit of shadowing on the right-hand edge of the picture tube, due to the ion trap. When I completely eliminate the shadow, the picture dims quite a bit. At maximum brightness, a sliver of the right side of the raster disappears. What you see is (so far) the best compromise I can get.

Here's a few screen shots using the Techpreservation test pattern DVD. They look better in person. Here's the "Indian Head"



And the TV Analyst:



Some linearity patterns. The circle looks a tiny bit egg-shaped on the right, but for the most part looks pretty good:





And lastly a still B&W image:

[earlyfilm]

Originally Posted by UberVacTuber

Thanks for the input. The picture quality seems pretty good, and the audio is clear. . . . . . .

Here's a few screen shots using the Techpreservation test pattern DVD.

Uber,

I think we have a little mix up in terms here.

I do not see an alignment problem with your pictures, but do see a lot of other adjustments off.

On a B&W set, alignment normally refers to IF and Tuner circuits, and unless you have the equipment and have done one before, I'd suggest that you have someone who has experience here watch you the first time you attempt one, because it is very, very easy to convert a small problem into a major one.

The incorrect adjustments that I see in your pictures are:

Neck shadow on right edge of the picture. (Possible causes: Yoke position, focus coil position and/or ion trap magnet position or weakness.)

re: The top of the picture looks a little wavy

Your sync seems to have a locking problem, which might be related to your linearity problems, but it probably is not. Substitute known good sync tubes. Try to get a schematic, like Sams that gives the voltages and check sync circuits. Suspect plate to grid caps of having leakage and you will have to open one end of them to check.

Once your sync is stable, trouble shoot the linearity issues.

Both the horizontal (do first) and vertical linearity adjustments seem off. If controls don't have enough range, suspect tubes first and then leaky caps. The Ryder schematic for the 30A1 on the ETF site gives good instructions for these adjustments.

Re: (the picture will twitch along with spikes in the volume).

Disconnect the speaker and put a 5 to 10 ohm resistor across the feed connector.
If this removes the video problem gently tap tubes in tuner/if/sync and video to see which one has gone microphonic. (Note: It is not necessary to put the load on the audio output transformer with a disconnected speaker, but on a tube set, it always is safer and a heck-of-a-lot less expensive than a fried output transformer.)

re: At maximum brightness, a sliver of the right side of the raster disappears.

Poor high voltage regulation. Check 1B3, horizontal output, damper, if check is OK, substitute a known good damper tube as testing.

Another less common cause of poor HV regulation is a gassy CRT, or leaking coupling caps in the grid circuits of the CRT.

Jas.

[UberVacTuber]

No mix up in terminology. Banderson answered my question and then the thread took a bit of a change in direction. Now that I'm getting good video I wanted to share it and compare it to his photos. I know you're being helpful with the suggestions, and I appreciate it. If I should have started a new thread instead, my apologies...

I don't have half of the equipment listed in the repair manual for the alignment procedure, nor did I intend to try it. After the comments given, it doesn't look like alignment is an issue.

I know there are still issues with the adjustments. I haven't had much time to do a lot of fine tuning. As I mentioned, the waviness is pretty much eliminated with the Horizontal hold. I hadn't fine-tuned it before I took the pics. The horizontal frequency has been adjusted per the instructions.

The ion trap is causing the shadowing. When I move it to a point where I get the maximum brightness, that's when the shadow is the worst. When I move the trap to a position that completely eliminates the shadow, the picture dims a fair amount. Are you saying that this is indicative of a high-voltage issue?

All the capacitors with the exception of the 10kV "Doorknob" for the CRT anode are new. I have both the Rider's and Sams schematics and the voltage and resistances check out OK. Originally I had too much width and the control had no effect. It turns out the damper resistor had failed and once replaced, the raster was the correct size and the controls then had good range. All the tubes in the cage check out good.

[earlyfilm]

Originally Posted by UberVacTuber

The ion trap is causing the shadowing. When I move it to a point where I get the maximum brightness, that's when the shadow is the worst. When I move the trap to a position that completely eliminates the shadow, the picture dims a fair amount. Are you saying that this is indicative of a high-voltage issue?

Nope! Now, I've put my foot in my mouth, as I misunderstood your discription.

Reduced sweep at high brightness is often associated with incorrect high voltage regulation, although blooming is a more common result. Any power tube drawing higher current than it should could shift the focus coil current or cut your width by pulling down the "B" voltage. This failure mode usually leaves the edges more-or-less straight when the image reduces, not curved like the neck of your tube.

Lets first tackle the neck shadow issue.

Generally (curved) neck shadow issues are yoke/focus coil/ion trap issues.

First adjust the ion trap for maximum brightness and refocus.

Is your focus adjustment at the end of it's range as that may be a clue?

With ion trap in the new brightest position, try repositioning the yoke and focus coil to reduce the curved shadow. (Mark both exact positions prior to moving and do the yoke first.)

If this helps, then tweak the ion trap again for max brightness.

These adjustments sometimes shift when the set is transported, or sometimes have been shifted by a prior repairman to fix an unrelated problem.

Originally Posted by UberVacTuber

Originally I had too much width and the control had no effect. It turns out the damper resistor had failed and once replaced, the raster was the correct size and the controls then had good range. All the tubes in the cage check out good.

Are you talking about the multi-tapped 50 watt R435 on the Ryder schematic?

If not which one?

Since you recapped, did you replace the .5mfd off of your width control with a .47mfd? It is a small change, but it could have pushed the width coil beyond its limit.

Have you adjusted the horizontal drive?

Jas.

[UberVacTuber]

"Is your focus adjustment at the end of it's range as that may be a clue?"

I think we're getting there.. I had been moving the focus coil around quite a bit as I was having a hard time getting the picture centered. It is in quite close and the best focus is close to the end of dial travel. I'll try your recommendation RE resetting the ion trap and then resetting the focus coil. The deflector yoke is locked in place and the tube up right up against the mounting. The only adjustment available on the yoke is to tilt the raster in order to get it level.

"Are you talking about the multi-tapped 50 watt R435 on the Ryder schematic?"
Yup.

"Since you recapped, did you replace the .5mfd off of your width control with a .47mfd?"
When I recapped the set I used exact-value replacements. The width coil now has good range and the raster fills the tube mask at about half travel.

"Have you adjusted the horizontal drive?"
I made an attempt to, as the directions say to use that first to adjust the linearity, mainly for the outer portions of the raster.

I'll tackle the shadow first, and report back on the results. Thanks!

[Penthode]

I have repaired/ restored a number of TVs over the years. If the set is more than twenty years old, I make a habit of checking alignment. I generally find that even changing tubes is enough to change the IF alignment noticably.

With practice, IF and RF alignment becomes very straightforward and does not take long to perform. I recently went through the alignment of my RCA 9TC275 in about two hours. And like other aspects of this hobby, it is fun!

The interesting thing is that prior to alignment, the picture and sound on the set was pretty good. However after alignment the picture was noticably better and the audio was louder and clearer. I have attached some snapshots of the RCA's IF response (full IF and the overcoupled transformer between the tuner and 1st IF stage) and the 21.25MHz sound discriminator. The full IF has markers at the adjacent channel video (19.75MHz), sound carrier (21.25MHz), 22.1MHz, 25MHz, video carrier (25.75MHz) and adjacent channel sound (27.25MHz). Note that the KCS29 chassis has two adjacent video, two adjacent sound and two sound traps in the video IF strip.

I particularly like the earlier sets (prior to 1953) because many sets then had four IF stages. The four IF stages were needed to get the four MHz bandwidth. After color was introduced, three or even two stages were the norm which limited bandwidth to 3MHz or less.

My opinion is that in the earlier days, the loss of bandwidth was not too noticable because broadcasters, especially remotely located network affiliates, were hard put trying to provide 4MHz on network programming. However today, with excellent quality DVDs and downconverted HD broadcast, the NTSC quality has never been so consistently good. The early four MHz sets can display the extra quality now to good advantage.