Procedure D. Light Pen Problems - IBM 3250 User Manual

Procedure D. Light Pen Problems
Note: This procedure will stop operations at all 325 ls controlled by this
3255.
Go to the 3255 that controls the 3251.
I
Open the front door of the 3255 and press the OPER button on the test
panel (see Figure 1-1). Wait for approximately 30 seconds.
I
On the test panel, is TEST NO 20 displayed with the OPER indicator on
and the ERROR indicator off?
YES NO
I
Report a 3255 problem to your IBM Representative.
Press the TEST button on the test panel. Return to the 3251 and, if
necessary, adjust the brightness and focus. Is the IBM test pattern
(see Figure 2-1) displayed on the 3251?
YES NO
I
Report a 3255 problem to your IBM Representative.
Check the light pen as follows:
1. Tip Switch: Observe the
>
sign near the bottom left-hand corner of the
test pattern while you press and release the tip of the light pen. Pressing
the tip should change the
>
to
<;
releasing the switch should restore the
>
sign.
2 Light Pen Detect:
a. Use the light pen to select each of the numbered intensity levels in
the left center of the test pattern. When levels 5, 6, and 7 are
selected, a
<
sign should appear alongside the level. Levels below
5 should not respond when selected.
b. Point the light pen at the word TEST in the pattern. The
<
sign
following TEST should change to
>.
Note: 3255 Model 2. When Single Element Intensification (SEI) has
been enabled, pointing the light pen at the word TEST should
brighten each character at which the pen is pointed to intensity
level 7.
c. Point the light pen at the
<
sign following the word TEST. An
*
sign should appear in the center of the test pattern.
d. Point the light pen at the spiral of short vectors in the right center of
the screen. The vectors following the vector selected should disappear.
(In this test, other components of the test pattern also disappear.)
If any of the light pen tests fail, check that the light pen is properly
connected at the front of the 3251. If this does not help, change the light
pen for a spare, or one from another 3251. Repeat the tests. ff the tests do
not fail now, the first light pen was faulty. Report the problem to your IBM
Representative.
To return the 3251 to the operating condition, go to the 3255 test panel and
press the OPER button, then close the front door of the 3255.
Chapter 2. Problem Determination Procedures 2-9