Dynamic Convergence (Online Test 7); Focus Adjustments - IBM 3279 2A Maintenance Information

3. Unless the raster is uniformly red, adjust
horizontal and vertical (H and V) 'PURITY'
potentiometers (see Figure 1-4) until the red
area covers the screen. Pay close attention to
the four corners.
Note:
That as the color becomes pure
it
also
becomes brighter and the adjustment should thus
~
made to leave the color both as pure and as
bright as possible.
4. Set the Normal/Test switch to Normal and back
to Test. Check that the raster is uniformly
green.
5. Press the following keys: CONTROL
0 Q
(alphabetic)
Check that the raster is uniformly blue.
6. If the green and blue rasters arc not uniform.
readjust the two purity potentiometers.
7. If any readjustment was necessary. return to
step 1. If raster colors are not acceptable on
the second time through the seq uenee, go to!
MAP 0000, Entry Point A.
8. Remove jumper D2Y02 to D2Y08.
5.3.3 Dynamic Convergence (Online
Test 7)
This procedure converges the screen. The
convergence pattern is stepped through 13 areai;)
and each is converged in turn.
Note: [f, after executing step I.e, )( -f or
)C
c-f appears in the operator information area,
another operator is probably using the convergence
routine. Wait a few minutes before trying again.
[f the terminal is attached to an [DPA, the same
effect occurs when the IDPA is in manual mode.
[f )( -f, )( c-f, or any other symbol appears in the
operator information area at any other time.
press the RESET key and retry the action.
1. Display the convergence pattern as follows:
a. Set the Normal/Test switch to Normal.
b. Hold down the 'ALT' key and press 'TEST',
then release both keys. 'TEST' appears in
the operator information area.
c. Press the following keys: / 7 ENTER
The pattern '-
I - I -'
appears at the center of
the screen. Adjust the brightness control if
necessary.
3279 MIM
The following steps (2 through 7) are repeated 13
times with the pattern in different positions on the
screen.
2. Use cursor control control keys to move the
green pattern until the red and green images are
superimposed (as closely as possible) to give a
yellow pattern.
3. Press the following key: R
4. Use the cursor keys again to move the blue
pattern until the blue and red images are
superimposed (as well as possible) and give a
pink pattern.
5. Press the following key: R
Go back to step 2 at least once to check.
6. Press the spacebar once or twice until the
pattern appears in the next position.
7. When you press the spacebar after converging
the 13th area, the (white) pattern appears
simultaneously in all J 3 positions. Until this
happens go back to step 2 to continue
converging.
8. On the first pass through the complete fine
adjustments, when all J 3 patterns appear. hold
down AL T and press TEST then release both.
The screen will clear. Go to section 5.3.4.
9. On the second pass through the 'complete fine
adjustments. when all 13 patterns appear. check
the convergence of each pattern. If any need
further adjustment, press the spacebar once and
return to step 2.
10. If, on the second pass, you cannot converge
the screen, then there is a fault. Inspect the
position of the convergence coil assembly, see
Figure 4-8, and correct it if necessary. If you
have exchanged the amplifier card go to section
5.3.9; otherwise, go to MAP 0600, Entry Point
A.
J 1. Hold down the 'AL T' key and press 'TEST',
then release both keys. The screen will clear.
5.3.4 Focus Adjustments
J.
Set up a bright red pattern as follows:
Turn the brightness control fully' clockwise.
Set the Normal/Test switch to Normal and
then to Test. .
Press the following keys: CONTROL 0 I
(alphabetic)
Chapter 5. Display Adjustments 5-5