Tektronix 2230 Service Manual page 272

Options— 2230 Service
The displayed address is offset from 0x80000 and is
a 4 digit hexadecimal number between F800 and
FFFF.
If an error is found, the address of the error, the actual
data found at the address, and the data expected at the
address are displayed on the crt:
COMM_RAM : @ <address> <actual data> < >
<expected data>
CMOS_RAM. This test checks the nonvolatile CMOS
memory. It is performed during Power-Up. Each stored
waveform is analyzed to determine if they contain errors. If
errors are found, the diagnostic either repairs or removes
the waveform. If seven or more errors are found, the entire
CMOS memory is reformated,
waveforms. If errors are found, the result of the recovery
attempt displayed on the crt:
CMOS : reformated
CMOS : recovered
If errors are reported, the instrument should be turned
off and then powered up again. An error should be ignored
unless it is repeatable.
R0M_MATCH. This test checks to see that all ROMs
are the correct version number ROMs. Each ROM is
checked during Power-Up. If an error is found, the version
numbers found are displayed on the crt:
ROMS:mismatch,nn,mm,oo
where nn, mm, and oo are the version numbers of the
ROMs in the instrument.
COMM_READBACK. Bit paths within the Option are
checked by COMM_READBACK. GPIB circuitry checked
includes U1335B and U1323. RS-232-C circuitry checked
includes U1236 and U1223. Data is first written to the
Option. Registers are then read and checked for the
correct data. If the data read back is in error, the actual
data read back is displayed on the crt:
COMM_RB : rt>(1) = ■ x2x, & rb(0) = y2yi
where:
rb is the data written to the Option (U1236 pin 7 or
U1335 pin 10).
7 -4 6
NOTE
erasing all
or
x, = y, — data read back from the Option (U1223
pin 3 or U1323 pin 3).
x2 = y2 = data read back from the Option (U1223
pin 2 or U1323 pin 2).
COMM_LOOPBACK. This test checks the GPIB con­
troller U1321 and associated circuitry by commanding the
controller to change its TR output and then checking the
TR output. If an error is found it is displayed on the crt:
COMM_LB : FGET NOT CLEAR
INPUT_PORTS. Two additional ports are added to the
INPUT_PORTS diagnostic. Option 10 adds U1322 and
U1323. Option 12 adds U1222 and U1223. They are
stored
labeled on the crt display as COMM_STAT U1x23 and
COMM_PARAM U1x22.
OUT_PORTS. Two output ports are added the the
OUT_PORTS diagnostic by the Options. OUT_PORTS is
run at power-up only. Option 10 adds U1335B. The pat­
tern seen on U1315B pin 10 is about an eight second
square wave. Option 12 adds U1236. The pattern seen on
U1236 is the same type of shift pattern as for the PRC
test.
Removal and Replacement Instructions
The exploded view drawings in the " Replaceable
Mechanical Parts" list (Section 9) may be helpful during
the removal and reinstallation of the GPIB and RS-232-C
assembly and its circuit boards from the instrument. Cir­
cuit board and component locations are shown in the
" Diagrams" section.
CABINET. To remove either the GPIB or the RS-232-C
Assembly from the instrument, perform the " Cabinet"
procedure
removal
Instructions" of Section 6. In step 4 of the procedure,
remove two screws and two post spacers and washers
from the GPIB side panel or two screws and four post
spacers and washers from the RS-232-C side panel.
MEMORY CIRCUIT BOARD. The Memory circuit board
can be removed and reinstalled as follows:
1. Remove the four flat-head screws that secures the
insulation and the Memory circuit board to the Option
Assembly. Remove the insulation from the Memory circuit
board.
COMM_LB : FGET NOT SET
or
in the "Removal and Replacement