Technical data

1-17
General Information
Preventative Maintenance
Preventative Maintenance
The following tasks should be performed at the yearly calibration interval.
Perform Mainframe Modification Inspection—86100A
Verify that the following modifications have been installed on your 86100A DCA.
Intermittent Front
Panel Keypads
Service Note 86100A-01
Serial Number: US4032 and below
Early production units had keypad assemblies with carbon ink on the printed circuit boards to-
gether with silver contacts on the rubber keypads. Over time resistance builds up on the contacts.
Newer keypads have carbon contacts.
This modification involves replacing the entire A7 Front Panel Assembly with the exchange front
panel assembly (refer to ”Replaceable Parts—86100A” on page 5-1 for the A7 Front Panel As-
sembly part number). The defective assembly must be returned to Agilent for credit.
Refer to ”To Remove the Mainframe Front Panel” on page 4-7 as applicable.
Intermittent or Slow
Floppy Disk Reads
Service Note 86100A-02
Serial Number: US4106 and below
On early DCA mainframes, the LS-120 disk drive would occasionally experience difficulty with
read and write operations.
A new ground connection was added on the A16 LS-120 Adapter Board Assembly. Replace the
A16 (part number 86100-66505) with the newer assemblies. Some DCAs may have already
received this modification; refer to Figure 4-15 on page 4-13. The new board assemblies have a
large ground trace added to the connector.
Refer to ”LS-120 Disc Drive Modification (86100A Only)” on page 4-12 as applicable.
Intermittent Problems
with Vertical
Calibrations or
Vertical Trace
Service Note 86100A-03
Serial Number: US4032 and below
On early DCA mainframes, the PLDs on the A13 Acquisition Assembly would occasionally go
into a write mode on power up. This will cause various symptoms such as vertical cal failure,
vertical trace at top or bottom screen, and loss of control of the vertical trace. Sometimes the
DCA fails to completely boot up leaving just the splash screen and the DCA buttons displayed.
Rebooting the DCA fixes the problem. If the DCA boots up properly, the problem will not
appear again.
Installing a PLD header plug on a connector on the A13 Acquisition Assembly can solve the
PLD lockup problem.
Refer to ”A13 Acquisition Board PLD Header Modification (86100A Only)” on page 4-36 as
applicable.