Atari Vector Monitor Repair/Upgrade

Contents:

11.2.1) COLOR PURITY

This information comes from the Wells-Gardner Service Manual.

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As far as adjusting purity (red gun hits red phosphors only, green gun hits green, etc.) and convergence (red, green, and blue guns hit adjacent dots to make white instead of separate colors), that is a whole different subject and the manual does a decent job of walking you through the procedure.

For best results, it is recommended that purity adjustment be made with display unit facing west or east. The display unit must have been operating 15 minutes or more prior to this procedure.

With yoke on CRT neck, set convergence assembly on CRT neck with the center line (of Purity Adjustment Magnet) over gap between grids No. 3 and No. 4. The convergence assembly consists of 3 sets of ring magnets with tabs (Figure 6).

FIGURE 6: 


-------------------             +-----------+
  \             /       /-+     |===========| <- Purity Adj.
 ////////////////======|  |     |===========| <- Red/Blue Adj. (4 pole)
  --------------        \-+     |===========| <- Red/Blue
    |  +--+  |                +-+----II-----+    on Green Adj. (6 pole)
    |+-|  |-+|                +-+-----------+
    || |  | || <- Grid No. 4      TOP VIEW
    |+-|  |-+|                /|\
    |  |  |  | <- last gap     |    Concentric Convergence
    |+-|  |-+|                 s    Assembly shown in zero
    || |  | || <- Grid No. 3   c    correction position.
    ||_|  |_||                 r
    || |  | || <- Grid No. 2   e  REAR VIEW
    || |  | ||                 w     __
    |+-|  |-+|                 |    /  \
    |  |  |  | <- first gap    |    |++| <- Tabs of ring magnets all
    |+-|  |-+|                \|/  _||||_   in vertical position.
    ||-|  |-|| <- Grid No. 1      / ____ \
    ||=|  |=||                ===/ /    \ \
    | \+--+/ |                 ~| |      | |
     \ |  | /                  ~| |      | |
      \|  |/                  -~-\ \____/ /
      ======                   ~  \______/
      ||||||                         II

Tabs of the 3 magnetic ring-pairs are to be in a vertical position which will produce a zero-correction state and facilitate adjustments. (Figure 6).

Connect a generator or game (self-test mode) which can generate a crosshatch patter of red, green and blue inependently and in combination of colors. Refer to "INTERFACE BOARD ADJUSTMENTS" for input signal level and pattern size.

With a green crosshatch pattern, pull the deflection yoke backward as far as it will go. The center vertical portion will be green. If green is not horizontally centered between other colors, move the 2 purity magnets with respect to each other in order to center green crosshatch on the screen.

Push deflection yoke forward gradually, until crosshatch is a uniform green (pur in color) across the entire pattern. The deflection yoke should be secured in place.

Both red and blue colors are to be checked for uniformity and true color. Reposition the deflection yoke, if necessary, to obtain optimum purity of all colors. Tighten clamp to secure deflection yoke.

11.2.2) STATIC CONVERGENCE ADJUSTMENT

4-Pole Magnets and 6-Pole Magnets are for static convergence.

  1. A crosshatch signal should be connected to the monitor.
  2. A pair of 4-Pole Convergence Magnets is provided and adjusted to converfe the blue and read beams (Figure 6). When the Pole opens to the left and right 45 degrees symmetrically, the magnetic field maximizes. Red and blue beams move to the left and right. Variation of the angle between the tabs adjusts the convergence of red and blue vertical lines.
  3. When both 4-Pole Convergence Magnet Tabs are rotated as a pair, the convergence of the red and blue horizontal lines is adjusted.
  4. A pair of 6-Pole Convergence Magnets is also provided and adjusted to converge the magenta (red + blue) to green beams (Figure 6). When the Pole opens to the left and the right 30 degrees symmetrically, the magnetic field is maximized. Red and blue beams both move to the left and right. Variation of the opening angle adjusts the convergence of magenta to green vertical lines.
  5. When both 6-Pole Convergence Magnet Tabs are rotated as a pair, the convergence of magenta to green horizontal lines is adjusted.

11.2.3) ADJUSTMENT OF DYNAMIC CONVERGENCE (Figures 7, 8 and 9)

[NOTE: This text refers to a monitor oriented in the proper horizontal position. Some games such as Tempest use the monitor rotated 90 degrees into the vertical poisition.]

  1. Feed crosshatch signal to the monitor.
  2. Insert a wedge temporarily and fix the Deflection Yoke so as to obtain the best circumference (Figures 8a through 9b). NOTE: The wedges may need to be moved during adjustments.
  3. Insert three rubber wedges to the position as shown in figure 7 to obtain the best circumference convergence.

NOTE:

  1. Tilting the angle of the yoke up and down adjusts the crossover of both vertical and horizontal red and blue lines (Figures 8a and 8b).
  2. Tilting the angle of the yoke sideways adjusts the parallel convergence of both horizontal and vertical lines at the edges of the screen (Figures 9a and 9b).
  3. Use three rubber wedges (tapered rubber wedges are used for thie purpose.)
  4. The position of each rubber wedge is shown in Figure 7.
  5. Do NOT force the permanenet wedges in. They are to be inserted until they just make contact with the yoke - after the yoke ahs been positioned.
  6. Fix the three permanent rubber wedges with chloroprene rubber adhesive.
  7. After the adhesive has dried enough to hold the wedges in place, carefully remove the temporarily installed wedge.
FIGURE 7 (Rear View) 

          _
         | | <---------- Temporarily Installed Wedge
      ___|_|___
 /\  /_________\  /\
/  \//         \\/  \ <- Rubber Wedge
\  //           \\  /    (60 degrees from Temporary)
 \// +---------+ \\/
 //  |   ___   |  \\
||   |  /   \ <--------- CRT Neck
||   | |     | |   ||
||   |  \___/  |   ||
 \\  |         |  //
  \\ +---------+<------- Deflection Yoke
   \\           //
    \\_________//
     \_________/
         | |
         |_|
FIGURE 8A 

+---------------------------+
|        B    G    R        |  Insert rubber wedge
|         \   |   /         |  from upper (right for
|          \  |  /          |  Tempest) side
|  R___     \ | /     ___B  |      |
|      ---___\|/___---      | S V  v 
|  G----------*----------G  | I I    / \    /
|      ___---/|\---___      | D E   /   \  /
|  B---     / | \     ---R  | E W  / DY  \/
|          /  |  \          |     /      /-----+
|         /   |   \         |     ------/------+
|        R    G    B        |          / 
+---------------------------+         /
FIGURE 8B 

+---------------------------+         \
|        R    G    B        |          \ 
|         \   |   /         |     ------\------+
|          \  |  /          |     \      \-----+
|  B___     \ | /     ___R  | S V  \ DY  /\
|      ---___\|/___---      | I I   \   /  \
|  G----------*----------G  | D E    \ /    \
|      ___---/|\---___      | E W  ^
|  R---     / | \     ---B  |      |
|          /  |  \          |  Insert rubber wedge
|         /   |   \         |  from lower (left for
|        B    G    R        |  Tempest) side
+---------------------------+
FIGURE 9A 

+---------------------------+     TOP VIEW
|+-------------------------+|        /\
||+-----------------------+||       /  \  /
|||                       |||      / DX \/
|||                       ||| +-> /     /|
|||                       |G| |   -----/||
|||                       B|R |       / ||
|||                       ||| |         ++
|||                       ||| |
|||                       |||  Insert rubber wedge
||+-----------------------+||  from left (top for
|+-------------------------+|  Tempest) side
+---------------------------+
FIGURE 9B 

+---------------------------+     TOP VIEW
|+-------------------------+|        /\
||+-----------------------+||    \  /  \
|||                       |||     \/ DX \
|||                       |||     |\     \ <-+
|||                       |G|     ||\-----   |
|||                       R|B     || \       |
|||                       |||     ++         |
|||                       |||                |
|||                       |||  Insert rubber wedge
||+-----------------------+||  from right (bottom
|+-------------------------+|  for Tempest) side
+---------------------------+

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Chapter 12) Improving your Monitor (preventing future problems!)

Now that you have your monitor repaired and adjusted, I'll discuss the variety of ways that exist to make your monitor (or rather, your deflection board) more robust and hopefully reduce or eliminate future failures.

Here is some text from the Major Havoc conversion kit installation instructions (TM-268). It describes the Atari sanctioned upgrades and includes instructions for converting all Wells-Gardner P314 Deflection Board PCB variations to Atari's "official" upgrade. Thanks to Tony Jones (ant@palm.cray.com) for sending this to me.

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12.1) Major Havoc Installation Instructions TM-268

[NOTE: Atari did copyright these documents and they are clearly marked with a copyright symbol.]

H. MODIFY THE WELLS-GARDNER DEFLECTION PCB

NOTE The following procedure applies to those Space Duel, Gravitar, and Black Widow games that used a Wells-Gardner display. If your game has an Amplifone display, proceed to I. Modify the Amplifone Deflection PCB [found earlier in this document].

Four versions of the Wells-Gardner display were used in the Space Duel, Gravitar, [Tempest,] and Black Widow games. Perform the preliminary procedure for all versions of the display, then refer to Table 3 to determine which version of the four displays was installed in your game and perform the additional procedure for that version. CAUTION! When soldering components to the display circuitry, apply just enough heat to provide a proper electrical connection. Excessive heat can damage the semiconductor material.

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