Nidek NT Series

NT-1000 no auto alignment
NT-2000 auto alignment Up/Down and side to side
NT-3000 auto alignment Up/Down, side to side and backwards/forwards

COMMON FAULTS

1. Instrument does not autofire on auto but does on manual
2. * readings or blank readings
3. Does not fire correctly and no puff coming from tube
4. Up/Down control operation
5. No video image but on-screen graphics
6. Picture on-screen will not stay still
7. No picture on-screen

1. INSTRUMENT DOES NOT AUTOFIRE ON AUTO BUT DOES ON MANUAL
This fault usually has the message "RETURN TO ORG" on the display and you will find that the safety lock does not operate.

REMEDY: Push the head of the instrument fully over to the left and lift up the joystick end of the head. Wedge something approx ½" thick between the head and base of the instrument underneath the joystick. I find the handles of a pair of pliers is usually about right. Look into the gap between the head and the base and you should see a small round peg approx 3mm in diameter pointing downwards. This should be about 1" to 2" behind the axle, between the axle and the joystick. Do not confuse this with the left / right microswitch which is several inches closer to the joystick and has a small wheel on it. Push the travel lock switch down and, using a long thin screwdriver, push the protruding peg towards the joystick. It requires a fair amount of force and will only move if the safety lock is pressed down. The peg should push back about 1 ½" and when it has moved, release the travel lock button and the peg should stay where it is. You should be able to see a recess in the top of the base into which the peg will locate. Remove the wedge and whilst lifting the head as high as possible, pull the head back as far as it will go. If all has been done correctly, the travel lock will now work and the "RETURN TO ORG" message has gone except when the head is pulled right back.

* READINGS OR BLANK READINGS
Instrument autofires correctly but readings are marked with a * or no reading appears

REMEDY: Check that the nose cone glass is clean. This glass gets very dirty very quickly because of splashes of moisture from the patient's eye. Clean with a soft lens cleaning cloth. If this does not cure the problem, call us for a service visit. There are many lenses inside the tonometer which need to be cleaned every 1 to 2 years depending on usage and a good service can usually make a great improvement to the operation of these units.

DOES NOT FIRE PROPERLY AND NO PUFF COMING FROM TUBE
This fault is usually caused by the piston seizing up in the cylinder. Undo the flap on the front panel and set switch to "test". Push the fire button in the middle of the joystick. The display should say PRS OK. If it does not, call us for a service visit.

UP/DOWN CONTROL OPERATION
Many Nidek instruments have a motorised UP/DOWN function controlled by rotating the joystick. A common malfunction is for the motor to intermittently turn in the wrong direction so that if you turn the joystick to go up, the head goes down and vice versa. This requires repair to the joystick mechanism so call for a service visit.

Video screen faults:

NO VIDEO IMAGE BUT ON-SCREEN GRAPHICS
If there is no image of the patients eye on the screen but the on screen graphics are still visible, firstly check the brightness and contrast controls located under the flap on the front panel. If a picture cannot be attained the video camera has probably failed. These can usually be re-furbished at a reasonable cost.

PICTURE ON-SCREEN WILL NOT STAY STILL
If the picture on the screen moves vertically and will not lock, try adjusting the vertical hold control which is located on the bottom of the head unit. Move the head fully to the right side so the bottom edge of the head unit can be seen. Level with the front of the screen are 2 potentiometers for vertical hold and horizontal hold. Whilst looking at the picture on the screen, adjust the potentiometers with a screwdriver until the picture is stable. If the picture cannot be stabilised or if it is stabilised but then unstable again if the unit is turned off and on, the monitor will require repair.

NO PICTURE ON-SCREEN
If there is no picture on the monitor or if there are just some white lines, the monitor will need repair. Sometimes, due to the age of the instrument, both the monitor and video camera need repair.

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