Troubleshooting - HP 9805A Service Manual

Chapter 5
TROUBLESHOOTING
I nitial Checks
Before an attempt is made to repair the Model 5, a few quick checks should be made to ensure
that a failure has actually occurred:
1. Verify the customer's complaint and ensure that the complaint is not due to some type
of user error.
2. Check for an improperly installed system; especially verify that any installed PROM is
being used with the correct type of keyblock.
3. If the calculator is completely inoperative, check and, if necessary, replace the line fuse.
If the line fuse blows again, refer to Table 5-1 for repairing the instrument.
4. Disconnect any installed peripherals and verify that a peripheral is not the source of the
trouble.
5. Use the special System Test PROM (-hp- PIN 9805-90031) to check calculator - see
'Using the System Test PROM' on the following pages.
NOTE
The Power Supply Test Assembly (5060-9199) should be installed in
one of the I/O slots (component side to the left) and each of the power
supplies tested before performing any of the following procedures. Each
power supply output should be within the tolerances given below.
Isolating the Problem
Supply
+5Vdc
+6Vdc
-12Vdc
+15Vdc
Tolerance
+4.75 to +5.25
+5.6 to +6.6
-11.2 to -13.2
+ 14 . 1 to + 16.3
Once the initial checks have been made and are found to be satisfactory, Table 5-1 should
assist you in finding the defective assembly.
•
•
The Model 5 'System Test PROM' is programmed to test either the basic calculator, the data
storage registers, the printer, or the plotter I/O card (which includes a cursory test of the
9862A Plotter). To use the PROM, perform the following procedure:
1. Switch the calculator OFF, and install the PROM. Then, remove any installed keyblock
and peripheral (other than the plotter) and switch the system ON.
2. PRESS:
!~.:;
i01Q\
H
0~O
Exerciser 10 is selected to test the basic machine. This key sequence can be used for
other exercisers by replacing the 10 with the appropriate exerciser number (20,30, or
40).
3. When 3.14 is pri nted and displayed, exerciser lOis complete and the resulting pri ntout
should be the same as the exerciser 10
listin~1
provided on the following page.
4. If any exerciser fail5
~o
run properly, see Table 5-2.
5. Exerciser 20 (Dat3Storage Register), 30 (Printer), or 40 (Plotter) may be run by
performing the instructions given below, then using the key sequence from step 2 (with
the appropriate exerciser number) to run the test.
REPAIRING
THE MOOEL 5
USING THE
SYSTEM
TEST PROM
5-1