KM light meter gone a bit odd

As title really, I checked my KM's meter against a couple of other known good bodies and found it was overexposing by anything between two and three stops. Any ideas? I know the Spotmatic meters tend to regard being within a stop of correct as ok, but I thought the K bodies were a bit more sophisticated?

Weird thing is I've had a few rolls of Ilford HP5 from this with no problems. Some of the frames are amongst the best images I've produced! I just thought I'd check it before using slide film as I realise that is much less tolerant of exposure errors.

I have had a brief look under the shutter speed dial and couldn't see much dirt or corrosion which could cause the problems, the body has presumably spent its entire life in an ERC (it came with one). About the only thing I can think of is that it came with an M42 adapter - could long-term use of this have upset the aperture coupling mechanism somehow?

Not that I have tested it but my KM's meter seemed fine when I used it last. I wouldn't have thought the adapter would cause problems. Maybe the camera just needs a CLA.

Sorry I cannot be more helpful.

K.

Well after a quick drop of lighter fluid and a lot of wiggling of the film speed dial it's now only over-exposing by one stop. I will check it again, but I can cope with that by just setting it to 400ASA for 200ASA film and so on. I'm not expecting pinpoint accuracy but something in the vague vicinity of my other bodies would be nice.

This does explain why the roll of Ilford SFX I used in it a few months ago came out a bit overexposed. I tend to shoot IR by metering, adding the filter, then knocking eight stops off the shutter speed to compensate for the filter. If the camera's metering was out of whack the error would have been compounded by the lengthy exposure times this technique produces.

A little cleaning under the shutter speed dial and the aperture coupling might also help. I have had similar issues with a KX film body.

Thanks, I'll give that a go too. I haven't had to dismantle too much of the camera yet, as this is a very tidy example I'm worried about marking screwheads and similar.

Need to check my KX too. It spent a few hours bagged in the freezer after I noticed a dust mite wandering around in the viewfinder, then overnight in the airing cupboard to make sure it was fully defrosted and dry. The metering seems fine but I've yet to try winding on and taking a photo.