***
No disc detected in unit.Troubleshoot the interrupt circuitry (refer to ta-ble 8-24).
TIl ... DIM Drive Troub ... ootlng .nd R ... ' (ContinueclJ
Repeat the disc test making sure that the disc is not write protected (the colored tab should block the hole). If the error message is repeated (with an unprotected disc), check the WRPT signal at pin 1 of U20 on the logic B PCA .
Ta .... 8·1. Disc DrIve Troubl . . . . o ... ' .ncI R...., (Continued)
...
1 G. Check pin 31 of UlS for a 125 ns wide pulse.
11. Check pin 29 of UlS for a 250 ns wide pulse.
12. Rerun the disc drive test.
I
Incllad. ActionThe waveform should appear as follows:
'It" ·'1.0 ..., . . . . La
.
• ..
~ •U the pulsewidth is not in the range 119 to 131 ns, adjust R44 on the logic B PCA.
The waveform should appear as follows:
.,. - t.. ..., ... -
0 ••If the pulsewidth is not in the range 238 to 262
115,
adjust R45 on the logic B PCA.If an error message appears, replace the logic B
PCA. .
8-40 Trou ... nd DI . . . tlcs Int ... _ 1 Computer
1"l1li1. "10. R .... TI . . . Clock Troubl . . hootlng.ncI ...
Use the following procedure to troubleshoot and repair a real-time clock problem. In each of these steps, always turn off the power before you connect or disconnect a cable or replace a component.
Not.: If the unit keeps time when connected to the power, but not when disconnected, the battery BTl is probably bad. Always check the battery voltage before replacing any components.
If the battery jumper PI is removed, or the battery is replaced, the time of day will have to be reset.
...
1. Set up the computer to troubleshoot the logic B PCA (refer to table 8-27).
I
Indicated Action2. Check the voltage of battery BTl. The nominal battery voltage is 3.0 Vdc. If the voltage is not in the range 2.5 to 3.5 Vdc, re-place the battery and reset the time.
3. If you get one of the following error mes-sages,' take the indicated action.
*** ERROR - 244
Replace U44 on the logic B PCA.*** ERROR - REAL T I ME CLOCK
Replace the logicB
PCA.failure
*** ERROR - Probable REAL TIME CLOCK failure
*** ERROR - REAL TIME CLOCK int.rrupt error
4. Adjust the RTC oscillator as follows: Moni-tor the oscillaMoni-tor frequency at pin 7 of U40 on the logic B peA. Use a six-digit fre-quency counter. (If a six -digit frequency counter is not available, and the customer requires the maximum accuracy, replace the logic B PCA.)
Go to step 4.
Troubleshoot the interrupt circuitry (refer to ta-ble 8-24).
Set the oscillator frequency to 32768 ±O.3 Hz by adjusting trim capacitor C43 on the logic B PCA.
Table 1-11. Sp_ker Trou ... hootin' .nd R .... lr
Use the following procedure to troubleshoot and repair a speaker problem. In each of these steps, always turn off the power before you connect or disconnect a cable or replace a component.
St.p
1. U you did not hear the ascending musical scale during the speaker test, set up the computer to troubleshoot the logic B PCA (refer to table 8-27).
2., While running the speaker test in continu-ous mode, check the waveform at pin 1 of U40 on the logic B PCA with an oscillo-scope set at 0.5 Volts per division and 1 millisecond per division.
3. While running the speaker test in continu-ous mode, check the waveform at pin 3 of U40 on the logic B PCA.
I
Indicated ActionYou should see a series of square waves of in-creasing frequency corresponding to the ascending scale. If the peak-to-peak voltage is within the range 9.5 to 10.5 volts, replace the speaker.
If the square wave is not present or the peak-to-peak voltage is not correct, go on to step 3.
If the peak-to-peak voltage is in the range 4.75 to 5.25 volts, replace U40 on the lOgic B PCA.
If the square wave is not present or the peak-to-peak voltage is not correct, replace the logic B
peA. ,
·8-42 Troubleshooting and Di ... tlca I ... Penon •• Computer
nable 1-12. HP·IR Tro.bI .... ooting and Repair
Use the following procedure if a failure of the built-in HP-IB is indicated (by either the short HP-IB test on the service ROM or the HP-IB test on the service diagnostic disc). In each of these steps, always turn off the power before you connect or disconnect a cable or replace a component.
Not.: The following procedure applies only to the built-in HP-IB. For problems with an external HP-IB interface, refer to the Integral Personal Computer Interface and Memory Mod-ule Assembly-Level Service Manual.
Itep while performing the following steps.
4. Probe pins 1 through 4, 9, 11, and 13
Figure
.-8.
Connector Pin As.lgnments,.. .... "t2. HP·I. Troubl . . . . otl ... and R ... ' (ContinueelJ
ltep
I. Probe pins 1 through 8, 10, 17, and 21 of connector J9 on the logic B peA. Refer to figure 8-8 for the pin assignments (pin 1 is nearest the power connector).
I. Probe pins 2 through 9 of U42, and pins 3, 4, and 9 of U43 on the logic B PCA.
7. Probe pins 12 through 19 of U42 on the logic B PCA.
8. Probe pins 14, 19, and 20 of U43.
I. Rerun the short HP -IB test on the service ROM.
I
IndicIIted ActionIf all of the pins are toggling high and low at J9, but some are not toggling at the back-panel con-nector, replace the HP-IB ribbon-cable assembly (which includes the back-panel connector).
1£ any of the pins are not toggling high and low at J9, go on to step 6.
If all of the pins are toggling high and low, but the corresponding J9 pins are not, replace the logic B PCA. Otherwise, go on to step 7.
If pins 12 through 19 are all toggling high and low, but any of pins 2 through 9 are not, replace U42. Go to step 8.
If any of pins 12 through 19 are not togglin~
replace U41. Go to step 8.
If pins 14, 19, and 20 are toggling high and low, but any of pins 3, 4, and 9 are not, replace U43.
If any of pins 14, 19, and 20 are not toggling, replace U41.
If an error message appears, replace the logic B PCA.
Int . . , •• PenoIUII CoIII _ _
the test menu. The printer will print out any error messages, and will then print out the test pattern shown in fi~ 8-9.
2. Take the action indicated for the error mes-sages that appear. If you need to
troubleshoot the printer control circuitry on the logic B PCA, prepare the computer as
The status-byte bits read from left (most signifi-cant bit 7) to right (least Significant bit 0). ,If a bit panel is flashing, troubleshoot the printer ROM, RAM, and CPU (refer to table 8-17).
Repeat the test. If the yellow light in the switch panel is flashing, troubleshoot the printer ROM, RAM, and CPU (refer to table 8-17).
Check the printer mechanism.