ZX-60 Shutter Problem. Is it the lens?

[paul_noble]

I have a ZX-60, with the Pentax 28-80mm zoom lens. The camera has begun

exhibiting a strange problem with the shutter.

 

With this lens, the shutter doesn't open. The mirror flips up, something in the

shutter moves, it makes all the right sounds, but no light comes through. I

shot a test roll and all 24 negatives were blank. Not extremely under exposed;

they were blank.

 

If I open the back and then close the latch (which fools the camera into

thinking that the back is closed), I can watch through the lens as I trip the

shutter. If I take the lens off and trip the shutter a few times, all looks

fine. If I put the lens back on, it will work once. After that, no light is

visible through the shutter. I find it odd that the camera won't work with a

non-autofocus lens, or if the aperture is moved off the "A" setting, but it

will work with no lens at all, but I digress.

 

The only other autofocus lens I have is a Sigma 70-210mm zoom. I just shot a

test roll with that lens and all pix came out perfectly.

 

If I do the same test, looking through the open back of the camera, the Sigma

lens works fine. If I take it off and put the Pentax lens back on, no joy.

Return to the Sigma; perfect. I can repeat this as often as I like. Nothing

changes.

 

It doesn't seem to matter which exposure mode the camera is set for, either.

 

Based on all this, it seems clear that the lens is somehow mis-communicating

with the camera and confusing the electronics.

 

The contacts on the lens seem to be intact and clean of dirt or corrosion.

 

Can this lens be saved? Is it worth it, or should I just buy a new lens?

 

Thanks,

Paul Noble

[alan_chan4]

ZX-60 has a crippled mount and it will work when the aperture is set to 'A' only. Could that be your issue?

[paul_noble]

I am aware of the "crippled" mount used on the ZX-60. The lens was set at "A". When it is moved off of the "A" setting, the camera just sits there and blinks an error code on the LCD display. It won't even try to operate the shutter.

 

The lens seems to work perfectly on my ME Super, which has a purely mechanical linkage between the camera and lens. It also seems to work on my P5, which uses Pentax-A lenses and has the electrical contacts.

 

I'm stumped. I've ordered a new Tamron AF 28-80mm zoom. If that works on the ZX-60, I'll have to assume that something is wrong with the lens.

 

Thanks,

Paul Noble

[alan_chan4]

Maybe you can try this. There is a moving arm at the rear of the lens. Sometimes the arm could be a little too close to the outer side and jam the stop-down mechanism of the camera. You might push it a little inward with finger and see if it works.

[paul_noble]

Alan,

 

I'll give that a try, but I'm not confident that this is the problem. As I said, it works fine on my all-mechanical ME Super. However, its possible that the camera clearances are different on the ZX-60 than the ME Super.

 

Thanks for the suggestion.

 

Paul Noble

[anthony_armstrong]

I have experienced similar strange behavior on both a Pentax ZX10 and a Nikon N2020. In both cases replacing the battery solved the problem - though why the old one had enough juice to operate the wind-on motor but couldn't trip the lower-current shutter magnets is a mystery to me. Perhaps the batteries were not bad and the fact I removed them caused a 'cold reboot' of the internal computer chip?

 

I would recommend trying a new battery before springing for a new lens

[alan_chan4]

The mirror motor inside all MZ/ZX cameras has to drive 3 things - stop down aperture mechanism, mirror down, and cork the shutter. It takes quite a bit of torque to do this. But winding film is a simple straight forward mechanism and motion. This might explain your experience.