[ChrisM]

I just purchase an MX and replaced the battery but the meter is very inconsistent. Sometimes it works (LED's on on) and sometimes it doesn't (LED's don't light up). I know of a good place to get it CLA'd but it rather save my money if I can.

Could it simply be a dirty electronic contact? How hard is it to remove the top?

Returning the camera isn't really an option because it came with an SMC-M 28mm f3.5 lens and the price I paid for the pair is about how much I'd expect to pay for the lens alone.

Thanks,
Chris

[Finn]

I would just send it in for a CLA. Eric Hendrickson (Home) is as we speak doing a complete overhaul on mine: new prism, new focusing screen, CLA, the works. It's costing me $93, which is money well spent for essentially a new camera. Mine had a meter issue where it wouldn't turn off, no matter what I did, so it ran down the battery really fast. Hopefully no longer.

[Ivan Glisin]

Could it simply be a dirty electronic contact? How hard is it to remove the top?

Most likely the meter switch that is easy to access by removing the bottom plate:

Does the Pentax MX have mirror lock-up? and repair tips

Scroll down and look at the second picture, where red arrow points. That is the meter switch and cleaning it should help. With removed bottom plate try operating shutter release button and see how it works, it is simple and easy to understand. To clean, cut a strip of paper, put it between contacts, press shutter release to sandwich it between contacts and gently slide paper out. Repeat several times if necessary. A drop of alcohol before cleaning helps.

Once cleaned and adjusted (I had to adjust mine) do the following tests: (1) with shutter release button free the LEDs should NOT operate; (2) with rewind lever in extended position and shutter release locked in "metering" position the LEDs should operate; (3) with shutter release in locked position and while applying pressure on it LEDs should NOT operate -- if they do contacts are too close and you'll have to gently flex outer contact plate to allow for a bit more clearance. (Lack of clearance in "L" position is the main cause of battery leakage, as paragraph just before the picture describes.)

If this does not help then shutter speed selector or aperture coupler contacts may need cleaning. However, if your problem is consistent at all shutter speeds and all apertures then it is most likely the meter switch that is easy to fix as described.

[Jerry Thirsty]

I've seen a similar problem on a K1000. The reason was that the base plate screw next to the tripod socket was missing, so the battery cap could flex away from the battery and lose the connection. The MX base plate and the K1000 baseplate are virtually identical in that area, so you could have the same problem. When the meter is mis-behaving, try pressing on the battery cap with your thumb and see if it comes on.

[ChrisM]

Finn - Eric is exactly who I had in mind.

Ivan - Thanks for that link. I tried that and the meter works when I put the bottom plate back on, but the meter only works for the first shot. Once I re-cock the shutter and press the shutter down half-way to activate the meter, it doesn't work, no LED lights. I even tried cleaning the contacts again (with sand paper) and the same thing happened. The meter only worked for the first shot.

Jerry - the camera is mechanically sound. No screws missing and no flex in the bottom plate.

Any more suggestions? It looks like a CLA is in my future.

[ChrisM]

Well, it's off to Eric at Pentaxs.com and will hopefully return with a working meter.

[Barbecueboy]

I just purchase an MX and replaced the battery but the meter is very inconsistent. Sometimes it works (LED's on on) and sometimes it doesn't (LED's don't light up). I know of a good place to get it CLA'd but it rather save my money if I can.

Ahem.. I had the same problem and it was the voltage of my batteries, I used two 1,4 V where you should use the 1,55 V varta or at least a 1,5 V.
Stupid, I know, but it might help you