[Hi John,
I have the SCA 382 and it is a very straight forward to use unit (unlike the SCA3802). The manual for the Metz flash would be more useful as the manual for these SCA300 series units only tell you how to attach the unit and how the 2nd curtain sync works.
I've used the SCA 382 with a metz 30BCT, 32MZ3 and 40MZ3i on an RX. There is *no* pre-flash exposure check on the RX, this function is only on the RTS III. I think you're describing the *post*-flash exposure check, where the 'flash ready (also called the OK symbol)' will fash a few times after the shot is taken. This OK symbol goes on and off about 3 times a second, and will flash a couple of times even if your flash is ready. ie. flash ready does not override the OK blinking symbol.
From my experience, the symptom you describe is on of the following:
a. The flash is not producing sufficient light, so the blinking symbol doesn't come on b. You're shooting in Contineous mode (but the blinking should come on if the last shot got sufficient light) c. The sensor in the RX is faulty
The blinking symbol does not depend on the SCA unit, as long as it is a coupled Contax, Metz or Yashica unit that allows the flash ready light to come on (and the body knows that it has a flash attached), the TTL sensor will sense the light and blink if there is enough light.
For the SCA 382 unit, there are only 3 functions associated with the SCA unit: * 2nd curtain Sync * TTL controled exposure * Flash ready light
To test your sensor, you need to have film in the camera as the sensor is calibrated to the grey color of film and not the black color of the pressure plate. I keep a roll of expired (unprocessed) film which I use over and over again for these flash tests. Take a photo of a blank wall from 3-4 feet away with you apature set wide open and the sync speed at 1/60. This will definately produce an overexposed shot, and the OK symbol should blink. If not, something is wrong with the RX's TTL sensor.
Off topic: the lack of the flashing symbol only means there isn't sufficient light. If it blinks, it means there is enought light, *or too much*. It cannot control over-exposure, even TTL can be over exposed if you are too close to the subject.
Hope this helps. ]