Fuses; Lithium Battery; Psu - Siemens TC12 Installation, Commissioning And Maintenance Handbook

Symptom
No power to handset terminal

3.4.4 Fuses

3.4.4.1 Outstation PCB Fuses
The outstation PCB is fitted with two fuses - FS1 and FS2; see Figure 18 for the
position of the fuses.
Fuse FS1 is used to protect the +5 V supply for the handset terminal.
Fuse FS2 is used to protect the +24 V for the 32 Digital Inputs.
Both fuses are 500 mA 250 V Quick Blow 20x5 mm, part number
518/4/90285/004.
3.4.4.2 5 V Supply Fuse on the OTU Module Assembly
The 5 V signal from the PSU is fitted with a 5 A, 32 V, 1.25" Quick Blow fuse (part
number 518/4/90286/007). This is situated on the side plate of the mechanics near
the PSU and is labelled FS1.
3.4.4.3 Internal Power Supply Fuse
The Power supply (part number 667/7/22671/000) manufactured by XP PLC type
NFS110-7602PK is fitted with a 5 A, 250 V fuse (518/4/90624/009). The power
supply needs to be removed and the case taken off in order to change the fuse.

3.4.5 Lithium Battery

The outstation PCB is fitted with a Lithium Battery (B1, part number
418/4/97186/000), see Figure 18 for the position of the battery on the PCB.
This battery must be replaced every four years.
There may be a label already on the battery showing the date the battery was
shipped. This should be covered with a label showing the date the battery is
fitted into the equipment. The replacement date is therefore four years after the
date on the label.
WARNING - Care should be taken when handling or disposing of Lithium

3.4.6 PSU

The power supply part number is 667/7/22671/000. To remove the power supply
remove the OTU PCB, loosen the four screws inside the PCB bracket that hold the
power supply in place. The power supply should now be pulled upwards until the
666/HE/43100/000
TC12 Installation, Commissioning & Maintenance Handbook
batteries. Refer to code of practice CP526.
Page 135
Possible Reason
Check handset fuse
Issue 10