User guide

901-10037001/1.1 FS 20/25 Operators Manual
Page 5.22 Maintenance and Troubleshootin
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Kongsberg Simrad Mesotech Ltd.
Port Coquitlam, BC - Canada
5.5.3.3 PWR/TTM Unit
The PWR/TTM Unit performs the following functions:
1. Generation of DC Voltages to run the LF Sub-assembly electronics.
2. Generation of High DC Voltage supplied to the Deployment Package (see
section 5.4.1).
3. Communication Interface (discussed in previous sections).
An FS20/25 System will be used as the example for an internal power supply failure
to the LF Sub-assemblies. The only apparent symptom is during the Connect/Detect
head process; there would be no head connected to either COM1 or COM2
(swapping cables would give the same result) and neither head would work if a full
system run up was done.
A failure to the high voltage generation can be verified by measuring the voltage at
the 3
rd
wire pigtail (56Vdc, 120Vdc or 200Vdc)
The following chart refers to internal PWR/TTM Unit failures.
Problem Action/Possible Cause
• Neither Vertical or FS925 Operates
-LF Sub-assembly Voltage Failure
• No indication of heads connected to
either COM1 or COM2 during
Connect/Detect Heads phase
• Both Vertical and FS925 heads react
when PWR/TTM turned on
• Will require repair by service
representative
• No Options: send PWR/TTM ashore
for repair
• Neither Vertical or FS925 Operates
-High Voltage Generation Failure
• Neither Vertical or FS925 reacts
when PWR/TTM turned on
• Heads connected to both COM1 and
COM2 during Connect/Detect Heads
phase
• Voltages not present at the 3
rd
wire
pigtail
• Will require repair by service
representative
• No Options: send PWR/TTM ashore
for repair