Kurzweil K250 - Page 136

The following table shows the integrated circuit pin numbers
to probe with the ocilloscope to observe these sinewaves:·
TABLE 2: ALIAS FILTER OUTPlITS .
U20 PIN 2
CHANNEL 1
U21 PIN 2
CHANNEL 2
U22 PIN 2 CHANNEL 3
U23 PIN 2 CHANNEL 4
U24
PIN 2 CHANNEL 5
U25 PIN 2 CHANNEL 6
U26 PIN 2 CHANNEL 7
U27 PIN 2 CHANNEL 8
U28 PIN 2 CHANNEL 9
U29 PIN 2 CHANNEL 10
U30
PIN 2
CHANNEL 11
U31 PIN 2
CHANNEL 12
The following, Table 3, shows the Sample D/A Converter test
points to probe if any of the
Channel Alias Filter outputs are
incorrect. The sinewaves at these points are not as
clean in
appearance.
Note:
Be sure to use the C2 sinewave at 5kHz sampling rate.
If a sample DAC output is bad, refer to the CGP procedure.
TABLE 3: SAMPLE DAC OUTPUTS
U62 PIN 20 CHANNEL 1
U63 PIN 20 CHANNEL 2
U64 PIN 20 CHANNEL 3
U65
U66
U67
U68
U69
U70
U71
U72
U73
PIN 20
CHANNEL 4
PIN 20 CHANNEL 5
PIN 20 CHANNEL 6
PIN 20 CHANNEL 7
PIN 20 CHANNEL 8
PIN 20 CHANNEL 9
PIN 20
CHANNEL 10
PIN 20
CHANNEL 11
PIN 20
CHANNEL 12
Kurzwell 250 Service Manual, Chapter 4
4-66