slit lamp randomly going on and off

[Matthew Kwong]

Hello group, This is a great resource that I have been scanning through. I have a question for the seasoned instrument maintainers;

My slit lamp bulb will randomly turn on and off for long periods of time.  It seems independent of movement of the slit lamp, or the arm, but I am thinking it is a loose connection.  What tool would be best to investigate further the loose connection? 

THank you for reading this post.

[Srinivasan]

Dear Matthew Kwong: I will be the happiest man if I get such questions every day. There could be many reasons for what you experience

1. Check the electrical supply of the clinic to which the slit lamp is connected. There could be some random lose connection
2. Check the power unit of the slit lamp. It could have a connection (a wire) that is not firm
3. Check the switch in the slit lamp (part of the power unit). It could have a spring that is not firm causing the random behavior  
4. Check the base of the bulb it may not be firm. Replace the bulb
5. Check the filament of the bulb by inspection. It could be broken but not fallen apart and so capable of making occasional contact giving the impression the bulb is good. Replace the bulb. 
6. Depending on the make of the slit lamp check the wire leading to the bulb it could get twisted and stretched as the illuminating system of the slit lamp is turned one side or the other (I have added this to make my list complete, you say the effect is independent of the movement of the slit lamp)

Please let the group know when you manage to rectify the defect. Best wishes. Thanks

[Matthew Kwong]

Thank you so much sir!

The reason was because one of the two screw that holds the bulb in the top housing was missing.  

Matthew

[Srinivasan]

GOOD. I am reminded of a poem I had come across may years ago (some time in 1945) when I was a student in high school

For want of a nail a shoe was lost

For want of a shoe a horse was lost

For want of a horse a soldier was lost

For want of a soldier a battle was lost

For want of a battle a kingdom was lost

All  for want of a horse shoe nail!

Small screws missing has been the culprit. You have found it. I am happy. Best wishes  Srinivasan