Motorola ASTRO Digital Spectra Plus Service Manual page 238

5-22
A
Inspect U201
No
Repair component
OK?
Yes
16.8MHz
Measure waveform at U201-39
Clock
should match Figure 6-12
Inspect R200,
No
Waveform
R201, and C201
correct?
Yes
Check SSI connections per
Figure 5. U201-35 = STD - T1
U201-34 = FS -T2
U201-33 = SCK - T3
No
Inspect U201-
OK?
35, 34, 33
Yes
Check SPI connections per
Figure 6. U201-44 = ADDAG_SEL
-T1
U201-43 = QSCKA - T2
U201-42 = MOSIA - T3
U201-41 = MISOA - T4
Chart C.28 ASTRO Spectra Plus VOCON TX Modulation Failure Sheet 2 of 4
October 28, 2002
Repair components
No
Yes
Repair oscillator
OK?
circuit
Repair U201
No
Yes
OK?
No
Inspect U201-
OK?
41, 42, 43, 44
No
Yes Measure wavefoorm at U402-17,
OK?
should match Figure 6-17
Repair regulator
circuit
Yes
No
OK?
Check Patriot supplies
L300 - T1 -3.0V
L301 - T2 - 1.8V
Repair U201
Check SAP connections per
Yes Figure 8. U402-7 = FS -T1
Yes
U402-11 = DCLK - T2
U402-13 = TXD - T3
U402-10 = PWRD - T4
OK?
Troubleshooting Charts
Check Patriot clocks
C326 - T1 - 16.8MHz
R428 - T2 - 32kHz
Yes
Inspect and repair
OK?
Patriot IC - U300
No
Repair proper clock
circuit
No
Yes
Replace U201
OK?
No
Continued on
C
next page
6881076C25-D