Problem Determination

This chapter describes how to isolate problems with the IBM 7171. Included, is a detailed procedure for resolving diagnostic, power and intermittent failures. Also addressed, are some of the more common setup problems, which are typically a result of incorrect cabling or configuring of a device attached to the IBM 7171, or the cabling or configuring of the IBM 7171 attached to the host processor.

If a problem exists, do the following:

1. Go to the "Symptom Index" on page 8-2, to find the symptom.

2. Go to the section indicated to the right of the symptom.

3. Perform the step-by-step procedure associated with the symptom.

8.1.1 Assistance for Problem Determination.

If problem determination procedures cannot be completed, then contact IBM for Service or Assistance.

Prepare to provide the following information.

Machine (IBM 7171) Configuration (number of ports) Serial number of the IBM 7171

Symptom (description of problem) Host type (model)

Host Operating System installed Channel & Control Unit address range

Company name, callers name, phone number for returning call.

Chapter 8. Problem Determination

8-1

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Symptom Index

Locate symptom in the following list; then go to the symptom code indicated to the right. The symptom codes follow the Symptom Index within this chapter. If the symptom is not found in the list, or, it can't be resolved through the procedure, then contact IBM for assistance. (Reference 8.1.1, "Assistance for Problem Determination. ")

Front End (TCC / CPU) related symptoms.

Unexpected or intermittent line drop (line disconnect) . . . F-1 Garbled data at terminal screen . . . F-2 Double characters 'Echoed' to the screen . . . F-2 Autobaud related problems . . . F-3 Port doesn't restart automatically . . . F-4 No data sent to terminal screen. (Enter Terminal Type:) . . . F-5 Specific range of ports can't present data to attached devices.F-6 Screen problems appear after entering the valid terminal type .. F-7 Modem Related problems. (strapping/configuring) . . . F-8 Printer overruns on data from host . . . F-9 Power Indicator does not turn on at Front Panel . . . F-10 Diagnostic failure at power-up. (red light(s) No Ready Light) .F-11 Intermittent Power or Diagnostic failures . . . F-12

Channel End (CA/CCC/CPU) related symptoms.

Can't VARY ONLINE or ENABLE device . . . C-1 Cursor to bottom right after

ENTER TERMINAL TyPE . . . C- 2 Interface Control Checks

GOT STATUS OF WRONG DEVICE WHEN CHANNEL EXPECTED STATUS

FROM ANOTHER DEVICE . . . C-3 7171 locks up on first readying

terminal with first write command . . . C-4 READY drops when 7171 switched online . . . C-5 Operational checks for a 7171 device . . . C-6

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IBM 7171 Reference Manual and Programming Guide

F-1: Unexpected or Intermittent Line drops.

• If Locally Attached (direct connection) PHYSICAL CONNECTION:

1. Confirm that cable wiring conforms to description in IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B).

or

-2. Explicitly configure the port to 'Locally Attached' Refer to section 9.8, "C - Configure IBM 7171 Ports" on page 9-7 of this manual.

• If Switched Network ... PHYSICAL CONNECTION:

1. Confirm that cable wiring conforms to description in IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B).

• If Leased Line ... PHYSICAL CONNECTION:

1. Confirm that cable wiring conforms to description in IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B).

or

-2. Explicitly configure the port to 'Leased Line' Refer to section 9.8, "C-Configure IBM 7171 Ports" on page 9-7 of this manual.

Chapter 8. Problem Determination

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F-2: Garbled data at terminal screen, Double characters echoed.

Line speed and/or line control parameters are inconsistent with attached device.

The line control parameters the port is initialized with, must be consistent with the attached device. The IBM 7171 is shipped with the following default line control parameters defined for all ports.

Port 0 is reset to these settings when the IBM 7171 is powered on, or receives a channel reset.

Seven data bits (7) Even parity One stop bit

The 'line control parameters' must be consistent with those of the attached device.

Reference the documentation (for attached device) for details on checking or mod-ifying the line control parameter s.

Verify that the attached device is configured for RS-232-C, asynchronous, full duplex operation. (Half-Duplex configuration may cause double character echo for each key depressed.) To confirm and/or modify the IBM 7171 line control param-eters, refer to section 9.8, "C - Configure IBM 7171 Ports" on page 9-7 of this manual.

Terminal Type Specification Errors

If no device type is specified for a terminal in Non-Volatile RAM (NV-RAM), the IBM 7171 assumes that the device is a terminal, and requests the terminal type from the user. If the wrong type (one that does not match the terminal) is entered even though it is a valid terminal type, the IBM 7171 will use the wrong Terminal Definition Table. This will probably result in the terminal malfunctioning.

To correct this situation, press the "Return to ENTER TERMINAL TYPE

Message:" key as described in "Return to 'ENTER TERMINAL TYPE:' Message"

on page 3-10.

If the user cannot get back to the "ENTER TERMINAL TYPE:" message via entries at the keyboard, he must cause the IBM 7171 to restart the communication line. This can be done for a locally attached terminal by powering the terminal off.

For remotely connected lines, intervening communications equipment (modems, port selectors, etc.) may prevent proper restart when the terminal is powered on and off.

Under no circumstances will the MASTER RESET function defined in section 3.1.7, "Local Reset and Control Facilities" on page 3-10 be useful in recovering from an incorrectly chosen terminal type table.

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IBM 7171 Reference Manual and Programming Guide ,

F-3: Autobaud related problems.

Define the line speed explicitly to the IBM 7171 and re-attempt the connection. If this resolves the link problem, then confirm the following points have been

satisfied:

1. The line speed that the attached device uses for the connection must be a sup-ported 'Autobaud' line speed. Refer to Chapter 5 of this manual for supsup-ported speeds.

2. Verify that the first character transmitted by the attached device, is a 'Carriage Return'or (x'OD')

3. Verify that the cable length conforms to RS-232-C. (Generally less than 50 feet.) This is with respect to the RS232-C cables between modems, and the device. In the case of Locally Attached devices, the direct connect cable should conform to RS-232-C specifications.

F-4: Port doesn't restart automaticaUy.

Confirm the following:

1. Refer to section F-1. Verify cabling and configuring information.

2. For Switched Network Modem attachment, verify that Data Set Ready (pin

#6) is dropped for a minimum of 200 milliseconds, between sessions.

3. For Leased Line Modems, verify that DSR is dropped.

In the event that DSR can't be dropped, explicitly configure the port as Leased Line, refer to section 9.8, "C - Configure IBM 7171 Ports" on page 9-7 of this manual.

Chapter 8. Problem Determination

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F-5: No data sent to terminal.

This section addresses the situation where no data can be sent to a terminal. (IBM 7171 output of any form.) If any of the following local IBM 7171 functions can can be completed, then the local connection to the IBM 7171 is effective.

• Character depressed, is echoed by the IBM 7171. (Confirm that the attached device is not echoing characters locally i.e. half-duplex)

• 'Enter Terminal type:' displayed.

• Host data on screen.

Host status message displayed or a partial 'Logo' displayed.

Send a note to the port in question, using the note command. Refer to section 9.20, "N - Send Notes to Attached Terminals" on page 9-23 of this manual.

No data sent to terminal. (ENTER TERMINAL TYPE:)

Prior to sending the attached terminal the 'ENTER TERMINAL TYPE' message, a number of events must take place.

1. The 'ENTER TERMINAL TYPE:' message, will not be displayed, if the port has been dedicated to a specific terminal type. Refer to section 9.8, "C - Con-figure IBM 7171 Ports" on page 9-7 of this manual. The default setting will result, after satisfying the 'Autobaud' function, in the displaying of the prompt.

2. The RS232-C control signals must indicate a line initialization sequence.

The message will be inhibited if the state of the RS232-C interface control leads suggests that the terminal interface has not completed a successful link.

The following interface control leads are expected to be active prior to the transmission of any data from the IBM 7171:

DSR Data Set Ready (Pin #6) CTS Clear To Send (Pin #5)

RLSD Received Line Signal Detector (Pin #8)

Refer to the IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B) for specifics regarding recommended cable wiring.

If the terminal is attached through a modem (leased or switched), the modem must correctly condition all of the monitored leads. For Direct Connect configurations, DSR and CTS are driven by the cable jumpering, and RLSD is driven by RTS from the attached device.

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IBM 7171 Reference Manual and Programming Guide

)

3. The IBM 7171 may need to be enabled for 'host communication'

• Confirm that the 'Online/Offline' is in the 'Online' position.

4. Confirm that' Autobaud' has been satisfied.

• Refer to section F-3 to determine if the problem is unique to 'Autobaud'.

F-6: Specific range of ports can't communicate with IBM 7171.

Note: In this section the procedure addresses the 'local' communication link, between the attached device, and the IBM 7171. Reference section F-5 for an under-standing of the local link being considered here.

• Are the devices failing to operate all related to ports associated with a particular TC Card (see Figure 8-2 on page 8-9)?

1. Turn the power OFF at the 7171 unit and reseat the TC Card that is suspect. Turn the power back ON at the 7171 and verify that the problem has been corrected.

2. Turn the power off at the 7171, obtain a replacement TC Card and replace the suspect TC Card. Turn the power back ON at the 7171 and verify that the problem has been eliminated.

• Is the problem associated with all devices associated with port 16 and higher?

1. Turn the Power Switch OFF.

2. Remove the TC Cards TCO, TC 1, and TC2.

3. Reseat the two crossover cables located in the rear of the Card Container.

4. Reinstall the TC Cards. Be certain that they are seated firmly.

5. Turn the Power Switch to ON.

• Is the problem associated with all devices associated with port 32 and higher?

1. Reference section C-l, of this chapter.(Sysgen)

• Do all of the ports fail to respond?

1. Turn the power OFF at the 7171 unit and reseat the CPU Card. Turn the power back ON at the 7171 and verify that the problem has been cor-rected.

2. If not, turn the power off at the 7171 and replace the CPU card. Turn the power back ON at the 7171 and verify the problem has been eliminated.

3. Be sure to restore any customer defined Terminal Definition Tables.

Chapter 8. Problem Determination

8-7

IBM 7171 Physical Layout

Figure 8-1 is an illustration of the front of the 7171. Familiarize yourself with the locations of the following key items:

1. On Line

I

Off Line Switch 2. Power On Indicator 3. Ready Indicator

4. Main Power OnlOff (II 0) Switch 5. Castor Locking Device.

6. EMC Pads.

1

----...-.:~-13

8--~

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Figure 8-1. IDustration of the Front of the 7171

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IBM 7171 Reference Manual and Programming Guide

RS-232-C port numbering

The RS-232-C ports are referenced in two ways. The first is the octal numbering indicated on the IBM 7171 Panel Assembly units (Refer to Figure 8-2). These numbers correspond to RS-232-C Panel Assembly units zero through seven and to ports zero through seven on each Terminal Controller Card.

The second is the system decimal numbering of the RS-232-C ports sequentially from zero to 63. The table in Figure 8-2 converts the octal numbering on the back of the IBM 7171 RS-23 2-C Panel Assembly units to the system sequential decimal port numbering. The hexadecimal equivalent of the decimal number is also

included.

Figure 8-2. RS-232-C port numbering conversion chart

Chapter 8. Problem Determination

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F-7: Screen problems appear after entering the terminal type.

• Confirm that the terminal type entered, is correct for the device being used.

Certain terminals may require a special Terminal Definition Table to be cus-tomized and loaded into the IBM 7171.

F-8: Modem Related problems (strapping/configuring)

1. Confirm that cable wiring conforms to description in IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B).

2. Verify that the attached modem has the following general characteristics:

a. Asynchronous - Start/Stop operation b. Full Duplex.

3. Verify that the modems at each end of the link are configured with compatible options.

Character lengths must be equal.

Modulation techniques are compatible.

• Baud rates must be equal.

Refer to the respective modem documentation for lists of options.

4. Configure the modem attached to the IBM 7171 end of the link such that it uses the RS-232-C leads in the manner defined by the EIA RS-232-C specifi-cation. Avoid using options that force various leads to an 'active' or 'true' state.

5. If Switched Network Modem attached:

• Verify that the modem attached to the IBM 7171 monitor's DTR (pin # 20) to determine if the modem should go off hook and answer the tele-phone.

Verify that DSR (pin #6) is dropped between sessions. (Minimum drop of 200 milliseconds.)

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IBM 7171 Reference Manual and Programming Guide

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F-9: Printer overruns on data from host.

A buffer overrun can occur if pacing is disabled to the attached device, or if the device does not support pacing characters. (XON /XOFF)

• Confirm the following:

1. Verify that the pacing characters being used for the device are equal to those being used in the IBM 7171 for the port in question.

2. If the device being locally attached is a write only device, it may deactivate either DTR or RTS to inhibit transmission when the buffer is becoming full. In this case refer to the alternate local attach wiring diagram in IBM 7171 ASCII Device Attachment Control Unit Description and Planning Guide (Appendix B).

Chapter 8. Problem Determination

8-11

F-10: Power Indicator does not turn on at Front Panel.

If the 7171 is operating normally, the Power Indicator on the front cover (see Figure 8-1 on page 8-8) lights immediately and the Ready Indicator lights a few seconds after the Power On (

I )

Switch is activated.

If the power indicator does not light, it is an indication that a malfunction exists in the 7171. If the ready indicator lights, it may mean that the power on indicator light is defective and that the 7171 is operational. If the power on light and/or card indicator lights, turn on for only an instant, proceed to Step 5 below. If neither light is on, proceed as follows:

1. With the ON-LINE/OFF-LINE switch to OFF-LINE, turn the Power Switch OFF (0), wait for at least 20 seconds and turn the Power Switch ON (

I ).

2. With the Power Switch ON, determine by inspection whether or not the two fans located behind the power supply are running. If you cannot hear them, you may have to remove the air deflector plate above the power supply by taking out the two thumb screws that secure it to the power supply. MAKE SURE THAT THE POWER IS OFF UNTIL AFTER YOU HAVE

REMOVED THE AIR DEFLECTOR. You can now observe the fans while you are turning power on. If one fan does not turn, replace it with POWER OFF.

3. If the fans do not turn, turn the Power Switch OFF (0) and check that the 7171 power cable is plugged into an active outlet. If so, check that the power cable inside the 7171 is plugged into the junction box located beside the fans and that the power supply is also plugged into the same box.

4. Replace the power supply and turn the Power Switch ON (

I )

to verify correct operation. If the spare power supply has two metallic shipping plates held in place with thumb screws on the under side, remove them before installing the supply.

5. If the power light and/or the card indicator lights turn on for only a short time when power is turned on, it is an indication that there may be a short some-where in the 7171.

a. Turn the Power Switch OFF (0), unplug any half of the cards and turn the Power Switch ON (I).

b. If the problem persists, turn the Power Switch OFF (0), unplug the other half of the cards while reseating the first half (this assures proper power supply regulation) and turn the Power Switch ON (I ).

6. If the power now stays on, turn the Power Switch OFF (0) and insert the cards one at a time, turning the Power Switch ON (

I )

after each card is inserted. Continue replacing one card at a time until you find the card that is causing the short, replace that card.

7. If the problem still persists, replace the power supply.

8. If you are unable to continue, invoke your Support Structure.

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IBM 7171 Reference Manual and Programming Guide

F-JJ: Diagnostic failure at power-up. (When Ready Indicator Does Not Light) If the Ready Indicator does not light, it is an indication that an error has been detected by the 7171 internal diagnostics. In most instances, the failure can be found by using PDP detailed below.

LEAVE THE POWER SWITCH (see Figure 8-1 on page 8-8) ON(

I).

POSI-TION THE ON-LINE/OFF-LINE SWITCH TO OFF-LINE.

1. If the Power indicator also did not light, see the section "PDP When Power Indicator Does Not Light."

2. Open the front door of the 7171.

3. Examine the individual cards in the Card Container and familiarize yourself with the location of the RED indicators on the individual cards. Refer to Figure 8-3.

Note that each card has an alphabetic group of letters marked on the surface of the part that cams the card into its slot position. A corresponding alphabetic group of letters are marked on the surface of the Card Container immediately above each card slot location (see Figure 8-3).

4. Match the card light patterns with the failing conditions patterns shown in Figure 8-4. Turn the Power Switch OFF (0). Remove the cards and replace as instructed. Insert the replacement card into the slot location of the removed card and seat firmly, using the card locking device. AVOID EXCESSIVE FORCE!

Note: If the failing condition (light pattern) does not match the failing condi-tions described in Figure 8-4, invoke your Support Structure.

5. Mark each card for identification, masking tape and a marking pen may be used. This is important to eliminate future mix ups with good cards.

6. The card will contain an identifying part number on a label on the component side. Obtain a replacement card with an equivalent part number.

7. Close the 7171 front door and turn the Power Switch ON (

I ).

8. The Ready Indicator should now light.

a. If it does, skip to the step below for the ON-LINE/OFF-LINE switch.

b. If it does not, continue.

9. Turn the Power Switch OFF (0) and remove and reinsert each card.

Note: Avoid excessive force on the card! Each card type has a unique con-nector pattern that will not allow it to be inserted into the wrong card slot posi-tion or in the wrong orientation.

10. Activate the power switch to the ON (

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position.

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11. Does the Ready Indicator light?

a. If the Ready Indicator lights, the problem is corrected. Go to the ON-LINE/OFF-LINE step below.

b. If not, invoke your Support Structure.

12. Activate the ON-LINE/OFF-LINE switch to the ON-LINE position.

13. The Ready Light should remain on. If the Ready Light goes out and all of the card indicator lights are on, the 7171 is not communicating with the Host System properly.

a. Verify that the Host end of the cables are attached correctly.

b. Inspect the channel cables and connectors for damaged or missing pins.

c. If the problem persists invoke your Support Structure.

14. Activate the Power On switch to the OFF(O) position.

15. PDP is 'completed, proceed with normal operation.

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IBM 7171 Reference Manual and Programming Guide

+12V -12V

Figure 8-3. Card Identification, Error Lights, and Voltage Test Points 1. Card camming device

Figure 8-3. Card Identification, Error Lights, and Voltage Test Points 1. Card camming device

Dans le document Reference Manual and Programming Guide (Page 182-200)