01753 524754Home > Help Files > Repair Tips > Tonometers > Topcon CT-10/CT-20
01753 524754
IMPORTANT NOTICE
Never open up your equipment in an attempt to alter the wiring or internal components.
Doing so could result in serious injury or death.
Check for split battery
The Topcon CT-20 can have a particularly serious problem which needs to be investigated. Move the head of the instrument fully to the right and examine the area of the base unit around the axle. Check for any signs of brown liquid on the base or rust on the axle. This problem is caused by a split battery on the PCB and results in the unit being beyond repair. Do not touch the liquid as it is poisonous.
Readings in ( ) or blank
If the instrument is firing correctly but the readings are in brackets or blank, the unit requires a service. Firstly check and clean the front glass around the puff tube. Clean the glass with a soft lens cloth and do not use any alcohol. The CT-20 front glass is held in with glue and will fall out if cleaned with alcohol. This also applies to the 2 small opaque lenses either side of the puff tube.
If the front glass is clean and the instrument still does not work correctly, call for a service visit. We can usually make good improvements to the operation of the unit.
Instrument not firing
If the instrument tries to fire but the air puff is very weak, it is usually caused by 1 of 2 problems. The piston may be stuck in the cylinder and if this is so, we can perform a small modification and service the assembly. Sometimes, the piston breaks from it's connecting rod and in this case, it will require a new piston/cylinder assembly. To test the unit, switch the instrument on and press the "test" button. If the piston is not working for whatever reason, it will display the message "NG-". If this happens, call us for a service visit.
Display Problems
If the picture on the screen is dim, the video camera or monitor or both may need repair. These can be done at a reasonable price. The CT-10 may also suffer from the on screen graphics not appearing. This can usually be rectified.
Flickering screen or instrument switching off and on
If the instrument switches itself off or the screen flickers, this is caused by an electronic fault which can be rectified. Call us for a service visit.