HP 3000 III Series Manual page 302

I/O Sys tern
through W7 (figure 7-21) determine the device number and, there-
fore, the DRT address associated with the Multiplexer Channel
PCA. A logic "1" is represented by the absence of a jumper and,
conversely, a logic "0" is represented when a jumper is install-
ed. The PCA's device number is normally %77 (no jumpers).
7-68. Port Controller PCA Servicing
The Port Controller PCA is a nonre·pairable PCA and must be re-
placed if found defective. No repair or servicing procedures are
required.
7-69. Selector
Channel Servicing
The Selector Channel consists of three PCA's; a Selector Channel
Register PCA, a Selector Cllannel Control PeA, and a Selector
Channel Sequencer PCA. Servicing information for the three PCA's
are contained in paragraphs 7-70 through 7-75.
7-70. SELECTOR CHANNEL REGISTER PCA. The Selector Channel
Register PCA is a nonrepairable PCA and must be replaced if found
defective. However, the PCA does contain jumpers and switches
(figure 7-22) that must be properly configured as discussed in
paragraphs 7-71 through 7-73.
7-71. Port Controller Channel Number. Jumper connectors XWl
through XW4 (figure 7-22) are used for the selection of one of
the three available channel ports from the Port Controller. Chan-
nel selection is made by installing a jumper in the jumper con-
nector corresponding to the desired channel.
7-72. Memory Size. Switch S3 (figure 7-22) is a 6-position
switch used to select memory word size. The switch positions and
corresponding memory word sizes are shown in figure 7-22.
7-73. Memory Interleaving. Two switches, S2 and 83 (figure 7-
22), are used for memory interleaving and, at present, must be
configured for non- interlea ving. (Refer to table 2-8.)
7-74. SELECTOR CHANNEL CONTROL PCA. The Selector Channel Control
PCA is a nonrepairable PCA that must be replaced if found defec-
tive. No repair procedures are required. However, the PCA does
contain the Error IDgging Register, a test switch and indicators
used for troubleshooting. Refer to the HP 3000 Series
I I I
CE
Handbook, part no. 30000-90172 for complete information on how to
use this PCA as a troUbleshooting aid.
7-75. SELECTOR CHANNEL SEQUENCER PCA. The selector Channel
Sequencer PCA is a nonrepair able PeA and must be replaced if
found defective. No repair or servicing procedures are required.
7-48