Extension Tubes - Contacts

Thank you Charlotte for the reference - which suggests that my problem is other, as my extension tubes (Triplus) do in fact have the seven contacts. They are of Japanese manufacture and quite solidly made.
I have found that a 30mm tube, for example, makes it much easier to see what I am focussing on when using the Pentax 100mm macro. Of course if I am unable to set an aperture from the camera then I am forced to stick at f2.8 and bang goes my depth of field!

Sometimes I wish I had stayed with the Sigma 105....

Regards
Roger

Tail end of this thread (didn't see what Charlotte wrote), but is your tube conducting with the body? Before I got my extension tube to work properly I had to sand it down ("short" it), works fine on -a now. Google for it, it's a common Pentax extension tube issue