Tektronix CSA7404B, Service Manual

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Troubleshooting
6- 84
CSA7404B, TDS7704B, TDS7404B, TDS7254B & TDS7154B Service Manual
Table 6- 13: Diagnostic LED (Cont.)
LED
Test method Testing Passed test
7 DRAM cell test with cache DRAM march test with out
cache DRAM march test. Test data lines. Write to address range set
by switch 1. Cache is disabled.
8 DRAM march test with out
cache DRAM march test with cache Test data lines. Write to address range set by switch 1.
9 DRAM march test with cache DRAM walking one Test data lines. Walk a one through DRAM memory location.
Cache is disabled. Walk a one through buss MEM_DL.
A DRAM walking one NVRAM walking one Walk a one through NVRAM memory location. Cache is
disabled. Walk a one through bus XPC_ISA_D.
H POST passed
L Boot parameters loaded and
waiting for host Program has loaded boot parameters and is waiting to
connect to host.
P Loading files from host Program has connected to host and is loading instrument files.
— Load process complete Files have completed loading.
Troubleshooting Using Reset Circuits
The Power PC (PPC) board uses a combination of removable jumpers and
surface mount resistors to manipulate circuit reset for troubleshooting.
There are three PCI busses on the PPC board, the MicroATX primary PCI bus,
L2 PCI bus, and the embedded PPC PCI bus. A hardware fault on any of these
busses can prevent Windows from starting properly.
Bus 0
J115
J114
Bridge
MicroATX
(Windows)
PPC (Instrument)
Transparent Bridge
Bus 1
MicroATX Primary PCI Bus
Tvia Video Adapter
Drawbridge
Figure 6- 46: The three PCI busses
Using jumpers J114 and J115 (see Figure 6--48 on page 6--86) you can selective-
ly remove components from the MicroATX primary PCI bus. This is useful
when Windows will not start. The Bridge board components on the MicroATX
primary PCI bus are the Intel 21152 transparent bridge, and the Tvia CP5202
video adapter.