Specifications

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2013 Deepwater Corrosion Services Inc. Specications subject to change without notice
ROV-II operation manual
11 Document 354-MN01-ENG Rev. C
10. Troubleshooting
10.1 The cell-to-cell value is greater than 5 mV topside or 10 mV subsea
The problem could be one of the following:
• One reference electrode has failed.
Repeat the bucket calibration (section 5.3). The electrode with the more positive reading is prob-
ably in error. Replace the reference electrode element (section 9.2).
• There is damage to the tail assembly cable or umbilical cable.
When recovering the ROV-II Probe from the dive, any cable damage can be quickly located and
repaired. Monitor the cell-to-cell value as the cable comes out of the water. If the problem is cable
damage, the cell-to-cell value will revert to the acceptable range (10 mV or less) as soon as the
damaged area of cable clears the water.
10.2 Both displays reading low (more positive) voltages
If both electrodes read low during a stab (more positive than (–)500 mV), the problem is probably
with the contact tip wire attached to the nose cone assembly. If the tip wire is damaged, a temporary
soft-splice repair can be made using ScotchKote® sealant (not included) and splicing tape. How-
ever, prolonged operation in this manner is not recommended. Order a new nose cone assembly as
soon as possible.
10.3 Recalibration
After any replacement or repair, recalibrate the instrument by performing a bucket calibration as
described in section 5.3.
Table 2 - Troubleshooting quick guide
Symptom Possible problem Action
Instrument will not calibrate
One electrode is bad
Zinc coupon is passivated
Electrodes are dry
See section 9.2
Remove zinc and clean with rasp
Soak in seawater for 30 minutes and retry
Both electrodes reading low Tip wire damaged
Remove probe tail unit, unplug tip wire,
remove nose cone, inspect tip wire and
repair with ScotchKote as temporary
measure. Order replacement nose cone.
Readings are not steady and
continue to change.
Voltmeter batteries are low
Poor structure contact
Replace voltmeter batteries
Re-stab to ensure contact.
One reading suddenly goes
less negative
Connector is ooded
Lead wire (ying lead) is nicked.
Check connectors
Inspect and repair / replace as necessary
Deep C Meter LED readouts
are blank
Not enough light to photo-cell
Batteries are dead
Pressure housing is ooded
Increase light intensity and re-direct to
center of lens.
Replace batteries
Go to backup; return unit to Polatrak.
10.5 If a problem persists or is not listed, please call our hotline at [phone] and ask for PolaT-
rak technical support.