Toshiba DK 16, DK8 manual DK16 Hardware Fault Isolation, Station Cable Continuity Check

FAULT FINDING

SECTION 100-816-500

MARCH 1993

Important Note:

Do not attempt to replace Fuse F201

7 DK16 HARDWARE FAULT ISOLATION

7.01If a DK16 hardware fault is suspected, check the hardware using the following procedure:

1)Make sure the BATT jumper plug (SW1 on the base unit motherboard) is in the ON position to save the system’s customer data base.

2)Unplug the PBTC battery cable from BATT connector on KPSU16 Power Supply (see Figure 2).

3)Lightly press the -24V circuit breaker to en- sure it has not opened (Figure 3). If the circuit breaker has opened and will not rest, remove assemblies (KSTU, KCOU, Expansion Unit PCBs, Expansion Unit) one at a time and try to reset -24V circuit breaker. If it is found lthat one of the removable assemblies causes the circuit breaker to open, replace that assem- bly. (See Section 100-816-205for PCB re- moval and Expansion Unit installation and removal.)

a)If the -24V circuit breaker cannot be reset with all removable assemblies dis- connected, disconnect the DC OUT con- nect (P9) from the Base unit motherboard and try to reset the -24V breaker.

b)If the circuit breaker resets when the DC OUT connector is removed, the Base Unit or Power Supply may be defective. Replace the Power Supply first (per Sec- tion 100-816-205) to avoid reprogram- ming the system.

c)If the -24V breaker continues to open ;after the power Supply is replaced, in- stall the original Power supply onto the DK16 Key Service Unit (KSU) and re- place the KSU with another KSU.

4)If the –24V circuit breaker is not open (Step 3) check the Power Supply DC voltages as follows:

Using a voltmeter or other device which checks voltage, measure the voltages referenced to frame ground (FG) at the DC OUT connector pins (test points) located on the motherboard (Figure 2). The voltages should fall within the ranges below. If the voltages do not fall within the ranges, unplug the DC power pins from the DC OUT connector and measure again at the same location; if the ranges remain unac- ceptable, replace the Power Supply.

§(FG) Yellow-Green Wire: 0V

§Yellow Wire: – 24V

•Range: –26.3V ~ –27.8V

§Red Wire: 5V

•Range: 4.5V ~ 5.5V

§Blue Wire: –5V

•Range: –4.5V ~ –5.5V

4)Check system third wire ground per Section 100-816-202.

5)If the –24V circuit breaker, DC power, and third wire ground are within required limits, remove all hardware assemblies, one at a time, and test to see if the fault is cleared (remove KSTU, KCOU, K4RCU and Expan- sion Unit PCBs and remove Expansion Unit per Section 100-816-205).

6)If the above hardware check did not clear the fault, call your Technical Support Group.

8 STATION CABLE CONTINUITY CHECK

8.01Voltmeter Test

8.02The continuity of the cable run between the DK16 KSU and the digital or electronic telephone is checked with a voltmeter as follows:

NOTE:

Perform the following at the locations indi- cated:

1.Modular block: Check all stations cables.

2.MDF: Check cable from KSU to MDF.

3.These tests also apply for troubleshooting cable problems with DDCB and PDIU-DS devices.

4.Refer to Section 100-816-208for appropriate MDF wiring diagrams.

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