Ushikata LS-25 Compass Reading Incorrect or Unstable Causes & Troubleshooting Malaysia
Ushikata LS-25 Compass Reading Incorrect or Unstable Causes & Troubleshooting Malaysia
Is your Ushikata LS-25 compass reading inconsistent, unstable or different from what you expected?
Do not immediately assume that the instrument is damaged.
Because the LS-25 combines a magnetic compass, telescope, horizontal and vertical angle systems and levelling functions, inaccurate field observations can result from several different causes.
These may include:
Magnetic interference
Incorrect setup
Poor levelling
Targeting error
Instrument movement
Physical impact
or an instrument that requires professional checking.
The first step is to identify which measurement appears incorrect.
First Question: Which Reading Is Wrong?
Before troubleshooting the LS-25, determine whether the problem involves:
Compass / Bearing Reading
Horizontal Angle
Vertical Angle
Bubble / Levelling
Telescope Sighting
Stadia Measurement
These functions rely on different parts of the instrument.
A problem with magnetic bearing does not automatically mean the telescope or horizontal-angle system is defective.
1. Magnetic Interference
If the compass bearing appears incorrect or changes unexpectedly, check the surrounding environment first.
Magnetic compasses can be affected by nearby magnetic or ferrous objects.
Potential sources include:
Cars
Trucks
Steel fencing
Heavy machinery
Steel columns
Large metal structures
Electrical installations
Magnets
Other significant ferrous objects
This is one of the most important checks before concluding that an LS-25 is faulty.
Simple Field Test for Magnetic Interference
If a bearing looks suspicious:
Move away from nearby steel or magnetic objects.
↓
Set up again in a suitable open location.
↓
Observe the same known direction.
↓
Repeat the reading.
If the compass behaves differently after changing location, the original environment may have been influencing the observation.
Never diagnose a magnetic compass using only one reading taken beside a vehicle or large steel structure.
2. Instrument Not Properly Levelled
The LS-25 incorporates a bubble system specified at 5′ / 2 mm.
Proper setup matters for reliable surveying observations.
A common mistake is:
Target visible = instrument ready.
That is not necssarily true.
The telescope can show a clear target even when the instrument has not been correctly levelled.
Before taking important angle observations, check the bubble and setup.
3. Unstable Setup
The instrument itself may be functioning correctly while the setup is moving.
Possible causes include:
Soft ground
Unstable support
Loose mounting
Operator movement
Vibration
Wind
Uneven field conditions
If the instrument changes position between observations, repeatability will suffer.
4. Wrong Target Sighting
This problem is particularly relevant in forestry.
Imagine looking through the telescope at a dense area containing many similar trees.
The operator takes one reading.
Then the instrument is moved and the observation is repeated.
This time, a slightly different tree is sighted.
The resulting angle is different.
The problem is not necessarily the LS-25.
The target itself changed.
Use clearly identifiable survey markers, ranging poles or reference points whenever possible.
5. Reading Before the Compass Stabilises
Do not rush magnetic observations.
After changing direction or moving the instrument, allow the compass indication to settle before recording the reading.
A good field workflow is:
Sight → Stabilise → Read → Record → Repeat
For important work, compare repeated observations.
6. Instrument Was Dropped or Knocked
Surveying instruments are precision devices.
If the LS-25 has:
Fallen
Been knocked heavily
Received a strong impact
Been transported without proper protection
or
Started behaving differently after an accident
it should be checked before important measurements are trusted.
External appearance alone does not prove that the instrument remains correctly adjusted.
7. Bubble Does Not Behave Normally
If the bubble cannot be positioned as expected, or appears inconsistent after the instrument is repositioned, investigate the setup and instrument condition.
Possible issues may involve:
Setup
Support
Adjustment
or
Instrument condition
Do not attempt random internal adjustment simply to make the bubble appear correct.
For professional equipment, unnecessary adjustment can create additional errors.
8. Telescope Image Is Difficult to Use
If the telescope image appears unclear, first check simple causes.
These can include:
Dirty external optical surfaces
Incorrect focusing
Condensation
Poor visibility
Insufficient target contrast
If the optical problem remains after normal external checks, professional inspection may be appropriate.
Avoid dismantling the optical system without the proper knowledge and equipment.
9. Horizontal Angle Does Not Repeat
The LS-25 uses a 5′ horizontal graduation with O-BAC zero-setting system.
If repeated horizontal-angle observations differ significantly, check:
Instrument levelling
Reference target
Second target
Setup stability
Observation procedure
Instrument movement
Then repeat the measurement.
If the same controlled test continues to produce abnormal results, the instrument may require checking.
10. Vertical Angle Appears Incorrect
The LS-25 incorporates a full-circle vertical scale with 1° graduation.
If vertical observations appear questionable, first check:
Instrument setup
Levelling
Target definition
Reading method
Whether the instrument has suffered an impact
Persistent abnormal results should be investigated rather than corrected by guesswork.
LS-25 Troubleshooting Checklist
ProblemFirst CheckBearing changes unexpectedlyMagnetic interferenceBearing differs near vehicleMove away and retestHorizontal angle not repeatableLevel + target + setupVertical angle questionableLevel + repeat observationBubble inconsistentSetup / instrument conditionTelescope unclearFocus / external opticsReading changed after a fallProfessional checkingMultiple functions appear abnormalInstrument inspection
How to Check Repeatability
A simple controlled repeatability test can be useful.
Choose a stable location and clearly defined target.
Take an observation.
Record it.
Move away from the observation and then repeat the setup and measurement according to the correct procedure.
Compare the results.
The purpose is not to perform an unofficial calibration.
It is to answer a simpler question:
“Does the instrument give reasonably repeatable observations under controlled conditions?”
If it does not, further investigation may be required.
Do Not Confuse Magnetic Variation with Instrument Failure
A compass is fundamentally different from an electronic angle instrument.
Magnetic observations depend on the magnetic environment.
Therefore, a bearing disagreement does not automatically prove that the LS-25 is defective.
Before sending the instrument for repair, consider:
Where was the measurement taken?
Was there nearby steel?
Was the comparison instrument also magnetic?
Were both measurements taken from the same position?
Was the same target used?
Was the LS-25 properly set up?
Troubleshooting should eliminate environmental and operator factors first.
When Should the Ushikata LS-25 Be Checked?
Consider professional checking when:
Readings remain inconsistent under controlled conditions
The instrument has been dropped
The bubble behaves abnormally
Angle observations cannot be repeated reliably
Optical performance has deteriorated
Mechanical movement feels abnormal
The instrument has been stored for a long period
The instrument is being prepared for important fieldwork
For professional surveying equipment, checking the instrument before a major project can be more economical than discovering a measurement problem after fieldwork has already been completed.
Repair vs Checking vs Calibration
These terms should not automatically be treated as identical.
Checking / Inspection
Determines whether the instrument appears to operate correctly and whether relevant observations are within the applicable checking criteria.
Adjustment / Calibration
Deals with measurement performance and the applicable adjustment or calibration procedure.
Repair
Addresses a physical, optical or mechanical fault.
An instrument can require checking without requiring repair.
Similarly, repairing a damaged component does not automatically mean every measurement function has been verified.
Should You Adjust the LS-25 Yourself?
Basic operator checks are reasonable.
Examples include:
Checking for magnetic interference
Cleaning accessible external optical surfaces correctly
Checking setup stability
Repeating observations
Inspecting for obvious external damage
But avoid unnecessary dismantling or internal adjustment.
Precision surveying instruments should not be adjusted by trial and error.
Ushikata LS-25 Checking & Surveying Instrument Service Malaysia
MTM Precision operates a Showroom & Service Centre in Puchong, Selangor for surveying-equipment support.
Our broader surveying service work includes professional equipment such as:
Total Stations
Auto Levels
Rotating Lasers
and surveying instruments from brands including:
Topcon
Sokkia
Nikon
Leica
Trimble
Pentax
For an Ushikata LS-25 or other specialised surveying instrument, contact us first with the model, symptom and required service so the applicable checking or service scope can be confirmed.
A photo or short video of the instrument and the problem can also help with the initial assessment.
Before Sending Your LS-25 for Checking
Provide:
1. Model: Ushikata LS-25
2. Problem: Bearing / horizontal angle / vertical angle / bubble / telescope / other
3. When the problem started
4. Whether the instrument was dropped or knocked
5. Photos of the instrument
6. Short video if the problem can be demonstrated
7. Your application
This makes the initial technical assessment more efficient.
Contact MTM Precision
MTM Precision Sdn. Bhd. (744811-A)
Telephone: +603-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com / enquiry@mtmpre.com.my
Website: www.mtmpre.com.my
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia.
For an Ushikata LS-25 with inaccurate, unstable or questionable readings, contact MTM Precision with the instrument model and symptom for initial checking and service advice in Malaysia.
16 Sep 2026
