Tektronix 11A52 Service Manual page 76

Dia nostics
executed in looping mode. As a byproduct of the way the hardware operates, the front-panel LEDs will flicker
during test execution. This behavior is normal, and does not indicate any fault.
The test generates a bitmap that indicates which ACVS channels are suspected of not operating properly. This
bitmap is returned in the Actual field displayed on the oscilloscope's user interface as a 16-bit hexadecimal
number. When the hex number is converted to binary, each bit corresponds to a specific pin number on a Sample
&
Hold Farm. Table 4-2 relates bits to Sample
&
Hold farm pin numbers:
(MSB)
(LSB)
TABLE4-2
Bits to Sample and Hold Farm Pin Numbers
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
11A52
1/20
1/22
2/20
2/22
1/19
1/23
2/19
2/23
1/17
1/14
2/17
2/14
1/15
1/16
2/15
2/16
The designation X/YY
indicates pin YY on
Sample & Hold Farm X.
For example, suppose the ACVS test failed and returned an Actual field of OOA4. Converting OOA4 to binary
yields 0000 0000 1010 0100 on bits 15 through 0. The ones on bits 2, 5, and 7 indicate that the ACVS channels on
Sample
&
Hold Farm #1, pins 17 and 16; and Sample
&
Hold Farm #2, pin 17 were not operating properly.
4-10
11A52 Extended Service Manual