Only see bright light effect in viewfinder and LCD

Could be your CCD - Minolta was bought out by Sony, they changed alot of their part numbers, but I do know of a Service Center in Florida.

If when switching from playback to LCD then Viewfinder and no preview display is visible in either LCD nor viewfinder then the switch is not switching. If the red battery light is on try new batteries as some functions are unavailable with low battery power or connect the AC adaptor to see if power is a problem. Does the menu work? Does the zoom function move the lens? If all is functional in the playback mode then the switch may not be making contact internally. Carefully apply pressure to the switch while slowly moving it between all 3 positions while seeing if any display changes both through the viewfinder and the LCD. If you are technically confident you can open the camera case and try bridging the switch poles with a small screw driver to see if the switch is defective or misaligned. EBay has had DiMAGE cameras listed for 'parts only' very cheap but the Z3 would not merit the cost of a camera repair shop. My last successful bid for a Z6 was $200 2 years ago. My first repair on a digital camera was pretty simple since inside the case is a single printed circuit board with little ribbon connectors that can be reseated at ZIF type connectors. Just be careful, slow and keep track of the screws and parts orientation. Any friend who fixes laptops can help you but a shop will cost you more than the camera is worth. Good luck.

well perhaps you forgot to switch it to the playback mode (red switch on the power ) in the record mode you have to choose between lcd and viewfinder . further more it is possible to switch the display off .

the camera needs enough power i reccommend 2500 NIMH
accu's

please use my real email account to deal with buying my battery door. $10 or for $25 I'll install it for you. keithtracypierceATcomcast.net

I am no expert at all, and the only camera I took apart was a Z3, which I did only to remove the battery door. dunno if Z3's similar to Z1; it IS similar to Z6 though.
Just a guess: electrical contacts at the viewfinder switch?

CCD sensor on its way out: sometimes still outputs ok but sometimes it does not. This problem only gets worse and you should have another sensor put in. Find out if Minolta repairs this particular fault on this model free of charge because many manufacturers do.

Is the lens cover completely retracted? Look at it.

With this function, you can adjust exposure, contrast, and saturation through the viewfinder itself, prior to image capture. You can check how your adjustments will look using either the viewfinder or the LCD monitor. This feature makes it easy to get the unique images you want in many different shooting situations. DiMAGE 7i is capable of setting contrast, color saturation and filter in the following increments. Contrast: In seven levels from -3 to +3 Color Saturation: In seven levels from -3 to +3 Filter: In seven levels ranging from warm (reddish) to cool (bluish) colors.

DiMAGE Z3 does not employ the Switch Finder that was employed in the Z2. Frame rate is 50 fps in both models, and smooth real motion monitor can be obtained. Specifications are as follows: Viewfinder : 0.3 inch, approx. 11.8 million pixels LCD monitor : 1.5 inch, approx. 7.8 million pixels

The DiMAGE Z3 has a 3.8cm (1.5 inch) digital-interface TFT color LCD Monitor, which displays approximately 78,000 pixels.

After a quick look at the manual you can find in the setup menu 3 "reset defaults" which shoud set you camera back to its first settings.