Hallicrafter 509 image shifted horizontally

[ohohyodafarted]

Just finished recap of a Hallicrafter 509 10". I have good vert and horizontal width and locking. I have good vertical height and locking. However as can be seen in the photo attached, the image is shifted by 50% horizontally. I assume the vertical bar up the center of the screen is the horizontal blanking interval that would normally be at the right side of the crt and out of sight off the face of the crt. Because I have full height and width I believe the horizontal and vertical of the deflection yoke is working so I do not suspect the yoke itself.

In the attached photo (although it is hard to see the detail of the image) the half of the image on the right side of the vertical bar is actually the left half of the full video image. (IE: the image is shifted to the left by 1/2 of the screen)

I am not real good at tv theory so I am hoping someone with a better technical background can point me in the right direction.

Thanks for your help!

[Kevin Kuehn]

I haven't looked at the schematic. I'm guessing the horizontal frequency is off by some multiple of what's correct. Any chance you could have installed a cap value that is off by one decimal place? Otherwise is there a course horizontal frequency adjustment that could be off?

[ohohyodafarted]

Originally Posted by Kevin Kuehn

I haven't looked at the schematic. I'm guessing the horizontal frequency is off by some multiple of what's correct. Any chance you could have installed a cap value that is off by one decimal place? Otherwise is there a course horizontal frequency adjustment that could be off?

Yes. I did adjust the horizontal frequency to get the H-hold to lock. H-hold locks very well and I do not have multiple images.

There is just one image. The image is shifted to the left on the crt by 1/2 of the screen. That is to say; the vert bar in the middle of the screen separates the image on the crt into a left half and a right half. The image on the left half of the screen is the right half of the full image and the right half of the screen is the left half of the image

If I remove the rf antenna input (or go off channel) I get a nice snowy raster. without the vertical bar up the middle. I can see full scan lines from left to right.

Likewise if I pull the 6al5 video detector between the output of the IF section and the input of the Video amp section, I get a nice clean raster. So it appears that what is being fed into the 1st video amp is a corrupted image (maybe)?

With all of that said I am leaning to an issue in the IF section.

I am going to try and scan the original Halicrafters schematic and post it in my next post.

And I will go back and check my cap values as you have suggested.

I already checked all the electrolytics to make sure I didn't switch the polarities, and that all checked out OK.

[ohohyodafarted]

VK wont let me upload the schematic. VK says file too big. I downsized the file but it loses too much detail and can not be read.

What do I do?

[old_tv_nut]

This is almost certainly not a problem in the IF, as the H sync and blanking looks normal in the picture.

I think the problem would be somewhere in the H sync waveform or H sweep waveform being fed to the H phase detector.

Can you post a link to a schematic for that section?

[ohohyodafarted]

Originally Posted by old_tv_nut

This is almost certainly not a problem in the IF, as the H sync and blanking looks normal in the picture.

I think the problem would be somewhere in the H sync waveform or H sweep waveform being fed to the H phase detector.

Can you post a link to a schematic for that section?

Tried to post it on VK but file is too big. I looked for it on the web but my set differs from the Sams which is posted at the ETF site and the OEM schematic is of poor quality at the ETF site.

I have an old email address for you. I will try to send it to that address.

Thanks Wayne
Bob Galanter

[old_coot88]

Assuming the scan frequency is correct, could there be a DC bias current running thru the yoke winding? Just a SWAG.

[old_tv_nut]

Originally Posted by old_coot88

Assuming the scan frequency is correct, could there be a DC bias current running thru the yoke winding? Just a SWAG.

A DC current would shift the raster sideways, not wrap it around.

Bob and I have started an email exchange. I think the problem is somewhere around the sync discriminator or its inputs.

[Electronic M]

Originally Posted by old_tv_nut

A DC current would shift the raster sideways, not wrap it around.

Bob and I have started an email exchange. I think the problem is somewhere around the sync discriminator or its inputs.

I agree. The H osc appears to be locking to the sync, but locking to it out of phase. The horizontal phase detector/horizontal AFC circuit is probably the issue though if the sync or sweep signals feeding it are somehow phase shifted that could also do it.

[old_coot88]

Originally Posted by old_tv_nut

A DC current would shift the raster sideways, not wrap it around.

Right you are. That was a senior moment/brain fart on my part. Dumb, dumb.

[ohohyodafarted]

Originally Posted by old_tv_nut

A DC current would shift the raster sideways, not wrap it around.

Bob and I have started an email exchange. I think the problem is somewhere around the sync discriminator or its inputs.

-------------------------------------------------------------------------------
This is what Wayne wrote to me................

Thanks. First let me say I never have trouble-shot one of these, so I can only make suggestions based on general principles.

Let me know: Do you want to proceed by email or on Video Karma? If VK, please copy the following there. It might be the best way to get someone with particular experience to help.

Have you tried subbing v11 and V12? Can you poke around this area with a scope?

The left half of V11 separates the sync. I’d guess it’s OK because you have vertical sync.

The right half of V11 is the phase inverter. One polarity is on the anode and feed the vertical circuit and the upper half of the sync discriminator.

The opposite polarity should be on the cathode of the inverter (R74) and feeds the lower half of the sync discriminator. A scope should show equal and opposite polarity waveforms at left sides of C58 and C59.

There should be a horizontal waveform of some kind coming through C61 and shaped by C60 and R79. I don’t know if it should be a pulse or a sawtooth wave or what on C60, but I’m thinking sawtooth more or less. If I understand the circuit correctly, the pulses from the sync phase inverter should be occurring in the center of the sawtooth, creating a neutral control voltage out of the sync discriminator and making the horizontal sweep line up with sync.

If V11 and V12 are good, I would check components in this area. Anything connected to right half of V11; anything connected anywhere on V12.

(FYI Vert sync is fed to the vertical oscillator through R75 and the following R/C integrator components to filter out the H sync and transmit a vertical pulse.)

Regards,

Wayne

[old_tv_nut]

if the image is a single image (it is) and is not skewed diagonally (it's not) [as shown], the frequency is correct. No need to try measuring it. Only the phase is wrong.

[Electronic M]

Originally Posted by old_tv_nut

if the image is a single image (it is) and is not skewed diagonally (it's not) [as shown], the frequency is correct. No need to try measuring it. Only the phase is wrong.

I agree with old TV nut.

Some counters are tricked by the non-sinusoidal horizontal waveforms so I typically adjust horizontal frequency by first measuring scope divisions between leading edges of horizontal sync pluses in a digital composite video source (DVD player, DTV converter, etc) then adjusting the vintage TV H osc for the same number of scope horizontal divisions between peaks (and usually the peak slightly higher than the hump on synchroguide based circuits) works well.... Probably not needed here, but useful if your frequency counter gets confused on complex waveshapes.

[Kevin Kuehn]

Originally Posted by old_tv_nut

if the image is a single image (it is) and is not skewed diagonally (it's not) [as shown], the frequency is correct. No need to try measuring it. Only the phase is wrong.

Is it not possible to have the horizontal oscillator adjusted wrong and still be locked, but out of phase?

[old_tv_nut]

Originally Posted by Kevin Kuehn

Is it not possible to have the horizontal oscillator adjusted wrong and still be locked, but out of phase?

There are two things happening.
1) The oscillator is locked. The phase locked loop is basically functioning. The free running horizontal frequency may be off center, but it is within the pull-in range of the loop.
2) It is locked at the wrong phase and is stable at the wrong phase. This should not happen whether the free-running horizontal frequency is correct or not.

Note that when the loop is locked, adjusting the free-running frequency +/- will rock the phase back and forth a bit to generate the correction voltage that keeps the locked frequency correct. This effect can be seen when the circuit locks at the correct phase as normal or the incorrect phase as shown here.

Something is making the control voltage out of the phase detector correct when the phase is 180 degrees from normal.