Teleconverter contact issue

[Peter Connan]

Need some help please.

I have a TC-1.4EII, and two lenses that can be used with it.

The 500mm f4 works fine, but recently the 300mm f4 AF-S doesn't focus. The lens works fine when fitted directly to the camera.

Any ideas on what I can try?

[Bjørn Rørslett]

Clean the contacts with a soft, clean toothbrush or similar, then try again.

Also, check that the spring-loaded contacts on both TC and lens move freely and are not jammed. If movement is insufficient, contact issues will develop. Sometimes the only solution is to disassemble the contact block and reshape or replace the silver pin(s) that caused the contact problem. 

[Peter Connan]

Thanks Bjorn, will fiddle and report back.

[Peter Connan]

Bjorn, cleaning has not solved the problem, and I can't actually see anything wrong with the pins.

Can you tell me which pins are used for AF (everything else seems to be working fine as far as I can tell)? Also, how does one go about dismantling the contact block? Don't want to bugger anything up...

[Bjørn Rørslett]

Pins 1-4 and 6 are grounding (#1), lens information, and light metering. The remainder are AF-and power-related.

Pin#1 is the leftmost when you hold the lens in the hand with the front pointing away from you.

Push the pins in one by one with a thin screw driver or similar, and see whether they immediately spring back when pressure to it is removed.