Honey I've Shrunk the PVM - A CRT Maintenance Log

Video Games
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It’s difficult to explain how to setup convergence through text. I want to make a video one day to explain the process. But hopefully this guide will help you.

Read

  1. Arcade Monitor - http://www.arcaderepairtips.com/wp-content/uploads/2016/01/guide_setup_adjust_arcade_monitors_v1.2.0.pdf
  2. Sony CRT-01 https://manualzz.com/doc/2314056/sony-crt-01-crt-tv-troubleshooting-and-diagnostic-training-…
  3. Read Service Manual for your TV

Big Picture

  1. Pushing the yoke front and back adjusts purity.
  2. Adjusting the yoke rings adjusts static (center) convergence.
  3. Tilting yoke left/right and up/down adjusts dynamic (outside) convergence.
  4. Adjusting the various pots and plate on yoke fine tunes dynamic (outside) convergence.
  5. Adding magnets fine tunes purity and convergence.

Understand this so you aren’t just wasting time.

Although the process to set the yoke in theory is very straight forward but in practice there are 2 big issues:

  1. Yoke has imperfections. To check convergence you look at symmetry between left and right or top and bottom. But since the yoke has imperfections it can be hard to tell if there is misconvergence or a yoke issues, which may or may not be correctable with strips).
  2. Although the yoke rings are used to adjust static convergence, they effect dynamic convergence so you might need to do touch

Step 0 - Prep Work

  1. Your rings are likely coated in paint. You’ll need to use cotton swabs and acetone to remove the paint. You might also want to remove the yoke and remove the rings to clean them if you have paint in-between the rings and on the metal spacers.
  2. Remove all wedges, magnets and convergence strips from your CRT. You might need extra strips which you can salvage from another step or make your own using permalloy magnets.
  3. Buy silicone and double-sided tape to lock the wedges, magnets and strips in place after you finish the calibration.
  4. Install 240p test suite onto your Wii or Dreamcast. Wii has good full 240p output so it’s the best version to use. Dreamcast is fine too. But stay away from the lower rez (224p only) 4th gen consoles.

Step 1 - Purity

  1. Display a pure green background image in 240p.
  2. Pull the yoke back until you see 3 bands: red, green, and blue.
  3. Inspect. Look at the figure in section 2-1 of the 27FV310 service manual. If the bands are PERFECTLY vertical and parallel then you’ll have really good purity. If the bands are diagonal or misshapen then you’ll have purity issues in that area and you might need to add magnets to the backside of the tube.
  4. Adjust the purity rings (2 pole magnets) so green is centered with blue and red equally spaced on the sides and push the yoke forward.
  5. Readjust rings if necessary to fine tune the purity. On these larger sets, the purity is very sensitive to minor changes. Try to keep purity rings as close to perfectly vertical and as closed as possible.

Step 2 - Static (Center) Convergence

To adjust static convergence you need to use the 4 pole magnets, 6 pole magnets and H Stat-VR701.

  • 4 pole magnets (ribbed end) adjust blue/red (magenta) vertical convergence.
  • 6 pole magnet (notched end) adjust green/magenta convergence.
  • H-Stat VR adjusts blue/red (magenta) horizontal convergence.
  1. Use 240p Backlit Zone Test
  2. Look at figure 3-14 of the 14M4U service manual. You want to spread the 4 pole magnet while keeping it symmetrical around the yoke to adjust red/blue vertical convergence.
  3. Adjust H-Stat VR to achieve blue/red horizontal convergence.
  4. Adjust 6 pole magnet to align green convergence.

Once done the center dot should be perfectly white.

Tips:

  1. It helps to set brightness at 120nits because the lower brightness results in a sharper image.
  2. If your G2 is set too high, you’ll have red flare as shown in the Sony CRT-01 manual.
  3. Use the GON setting to disable the green gun when doing magenta convergence.

Step 3 - Dynamic Convergence.

To adjust dynamic convergence, you’ll need adjust the follow parameters. Not all are available on all models.

  • Yoke Tilt: up and down.
  • Yoke Tilt: left and right
  • TLV1/HTRP - Adjusts HTRP size and TLV
  • TLV2 - only adjusts TLV
  • YCH
  • XCV - Adjust using the plastic dial or using an PLASTIC hex key into the slug, depending on the set. DO NOT USE A METAL ALLEN WRENCH OR ELSE YOU WILL DESTORY THE SLUG AND NEED A NEW YOKE!!! https://www.tubesandmore.com/products/alignment-kit-gc-electronics-color-tvs
  • TLH plate (not all yokes have/need the TLH plate)
  1. Use the 240p Linearity pattern and cycle to the version with an overlaid grid.
  2. See upper figure (a) and (b) in the dynamic convergence section of the arcade monitor PDF. Pull the yoke up to converge red/blue at the top and bottom of the screen. Adjust YCH VR to fine tune vertical convergence and XCV to fine tune horizontal convergence.
  3. See lower figure (a) and (b) in the dynamic convergence section of the arcade monitor PDF. Tilt yoke left and right to adjust parallel convergence. Fine tune top and bottom convergence with TLV, and likely TLV1/HTRP. Fine tune right and left convergence with TLH plate.

Tips

  1. To adjust HTRP. Disable BON and RON to display a green-only mode. Then use the linearity pattern with grids and dots to adjust the size.
  2. You want might to adjust tilt:up and down while adjusting purity as it as a large impact on corner puriety.

Step 4 - Final steps.

  1. Adjust the final set of rights on the VM board. Open/spread the rings while keeping them symmetrically around the horizontal axis of the yoke (opposite the 4 pole rings which must be symmetrically around the vertical axis). This will adjust VCEN aka the vertical geometry bowing.
  2. Set wedges in place and lock them in with silicon.
  3. Set convergence strips in corner.
  4. Add magnets to correct for purity issues.

Tips

  1. Only put 2 strips in each corner MAX.
  2. In general red/blue corner misconvergence is easy to fix with a strip but other types of misconvergence are difficult or impossible.
  3. Place purity magnets as far away from the yoke to minimize geometry warping.

Conclusion

Hope this helps. The process isn’t TOO difficult but it does require experience. In my experience, all consumer sets can be improved dramatically with a convergence adjustment. If you aren’t feeling very confident. Don’t remove the yoke and only do a static convergence adjustment. That alone should help quite a bit. In fact, I always start by doing a static adjustment first and then determining if I need to reposition the yoke depending on purity or dynamic convergence.

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