I need help with my Nikon F4s

[pan_giannakis]

Hi everyone,

I recently acquired a Nikon F4. It seems to be working ok except from when i select the silent mode Cs where this is what happens.
Sometimes, when i press the shutter button, it lifts the mirror and open/closes the shutter but does not advance the film. The readings on the viewfinder switch off and requires a gentle tap on the shutter button to complete the cycle (i.e. sound like advancing the film and bring the LCD reading back on).
Sometimes this does not happen and the Cs works ok.
On the rest advance modes (S, CL, CH etc...) it works fine.

Any suggestions why that might be?

Thank you.

 

[shutterfinger]

Verify that the Nicd-LR6 battery switch is in the correct position for the battery type you are using. Clean any corrosion off the battery contacts, battery contacts should be bright and shinny. Install a fresh set of batteries. The built in battery test will show both lights, LR6 batteries, in a static condition but no lights once the shutter button is pressed with marginal batteries. New LR6 batteries will read 1.55-1.56 on a digital volt meter. A battery that reads 1.50 is too weak for the camera to work properly.

 

[pan_giannakis]

Thank you Shutterfinger for you reply.
I cleaned the contacts (they are bright clean with no signs of corrosion) and the batteries are brand new. Any other suggestion as to why it might be happening sometimes and not others?

Regards

 

[zanxion72]

I think that the motor drive is struggling advancing the film. When it goes at full power it manages to get to the next frame successfully (but I bet slower than a properly working F4). Don't want to let you down but it will start doing the same in the other modes too. And when it does it will not be worth repairing it.
Winding issues had been the cause I had sold (for parts) my F4.

 

[shutterfinger]

I seen "New" batteries be bad. Try another set from a different batch. Press and hold the battery check button then trip the shutter, if both battery lights go out then the batteries are weak.
If the body has a lot of wear then I'll agree with zanxion72 on the motor going out.
If the body looks very good to new then its possibly dried out lubrication causing the drag. It will still be pricy to have the body serviced.

 

[pan_giannakis]

Hm... funny you should mention this shutterfinger. I loaded it with new batteries. Holding the battery check button, both LEDs are on (batteries fully). If at the same time i press the shutter button (while keeping the battery check pressed) the battery LEDs go off and back on instantly. At times it goes to one LED on and then both LEDs on.