Mamiya rz67 65mm lens problem ?

Hi
I recently bought a 65mm lens for my Mamiya. Loaded up some film and tested it out on Sunday, today I processed the film and found out there wasn't any exposure.
Checked I put the film in correctly, was ok checked the lens and found it not to be working.
Not sure what is wrong with it. If I take the back off and set the shutter button to no battery and press it, it seems to close (the curtain) before the camera shutter. Sometimes it will work and I will get a glimpse of light, but mostly it wont. If I set the lens to lock open, it might work 6 times then stop then start again. Ive cleaned the contacts, the lens itself looks in perfect condition, everything seems to work on it.
I have 2 other lens and they work flawlessly. Cant see any difference.
The battery is OK.
I have cocked the lens.
I can manually close the lens and release, everything works the same as the other 2 lens, but once I put it on the camera it is very intermittent.

I have had a look in history but cant find anything similar to this problem.

Am I doing something wrong.....its driving me nuts. Any help will be appreciated. Thanks.

I would look to see if you're in mirror up mode. That could cause what you describe.

Thanks but no. Other 2 lens work fine.

I can cock the lens off of the camera and fire it no problems. Once on the camera it wont fire, even after pre cocking the lens.

The only thing different between the lens is the cocking pins have a little more resistance on the 65mm lens. What I think is the problem is the camera hasn't quite enough strength to complete the firing of the lens.

Can I use a bit of silicon spray to put in the slot where the pins are? Or maybe there is some adjustment in the camera.....dont know any advise would be appreciated.

The one on the right.

Actually When the small shutter lock pin on the lens is pressed down as it should be the cocking pins spin fine. Maybe the camera isnt depressing the shutter lock pin enough. Not sure if it can be tensioned?....anyway think Im getting closer to what the problem is.

No thats not it either. That small switch on the camera has nothing to do with the lock pin. There is a raised cylinder on the camera that holds the pin down.

Sorry to ramble on.

Cant work out why it wont fire once on the camera and the other 2 do. Will need to empty my only film back and try something different.

The cocking pins on the 65mm lens were a little tight to fire and the camera didnt have enough puff.
So I took the front plate off to take a looksy.
Decided to try and take the chrome ring off to get a better look at how everything works. Couldn't work out how to disconnect the electronics so left attached. There were 8 very thin small washers that I didnt see exactly where they were positioned or what they did???? Think they were just spaces to keep even pressure under the chrome ring??
Lubricated moving parts best I could, turned the cocking cog a notch so it would be more positive towards firing. That helped firing but then the lens wouldnt cock.
After a few goes and some testing (a lot of testing)I finally got it right, so it would cock and fire. Gave everything else a clean and lube, where I could get to with out being too invasive.......and low and behold it seems to be working. So basically the camera just needed (needs) a service.....lets hope so.
Ended up leaving the 8 thin washers out till I can find out were they exposed to be.