Pentax ME Super Troubleshooting

The LEDs in the viewfinder don't light up.

Install new batteries in the camera to ensure that low battery voltage is not the issue. Batteries should be inserted with the negative side facing the battery compartment cover.

Check the contacts in the battery compartment. Old leaky batteries are a common problem and the acid can corrode battery contacts. Vinegar can be used to clean the corrosion.

Corrosion can also occur inside the camera. Remove the top cover and check the voltage at the red wire. It should be around 3.0 V. If it is lower, the connection to the battery compartment may be corroded.

The batteries die in a day or two when the camera is in auto mode.

The camera uses a momentary switch on the shutter button to turn on the meter. When it is pressed half way, a contact closes and turns on the light meter. When the button is released, the contact opens and the light meter turns off after about 30 sec. If the contact is not properly adjusted, it may not open when the shutter button is released. The light meter will stay on and drain the battery.

If this malfunction is occurring after a repair, it's possible that a short was created during reassembly. Check the solder connections in the area of the shutter button switches. Use a continuity probe to identify shorts between wires that should be isolated. Disassemble and reassemble if necessary.

The mirror flips up and down but it is slow. There is a delay in actuation after pushing the shutter button.

The ME Super has an air damper attached to the mirror mechanism for noise and vibration reduction. Inside the damper is a rubber bumper. Over time, the rubber can degrade and start to gum up the sliding action of the damper. This is typically the cause of a slow mirror. Follow the Pentax ME Super Mirror Box Service to clean out the old rubber bumper.

The reflex mirror in the body of the camera is stuck in the up position blocking the viewfinder. The shutter won't fire and the advance lever is locked.

This is usually caused by a failure in the mirror box mechanism. After the shutter fires, the closing curtain triggers a latch allowing the mirror to return to its viewing position. As the camera ages, some of the rubber bumpers on the mirror box degrade and get sticky. The mirror return latch no longer moves freely at it gets stuck in the up position. The old rubber bumpers need to be removed and the mechanism cleaned (see Pentax ME Super Mirror Box Service).

There are also some small rubber components in the shutter unit that can degrade. Sometimes the residue will make its way onto the shutter blades and seize the shutter. In this case, the closing curtain of the shutter won't trigger the mirror return and it will stay in the taking position, locking the camera. See the guide on servicing the shutter of the Pentax ME Super to remove and clean the degraded components.

The advance lever winds continuously but is unable to cock the shutter. The camera won't fire.

This is a different failure mode but is also caused by degraded rubber on the mirror box. In this case, the latch that holds the mirror spring in the charged position gets stuck. The mirror can't charge, which also means the shutter won't fire. The old rubber bumpers need to be removed and the mechanism cleaned (see Pentax ME Super Mirror Box Service).

When winding the camera, the shutter will fire without pressing shutter release. The mirror also rises as the advance lever is turned. Sometimes only happens when a lens is attached.

This is most commonly seen after servicing the mirror box. It's typically caused by a slightly slow return of the mirror, which prevents the mirror latch from catching (see pic). Sometimes it only occurs when a lens is attached because the mirror mechanism also has to push the aperture tab on the lens back to wide open, adding just a bit more resistance to the system.

It can usually be fixed by revisiting the mirror mechanism and making sure there is no extra resistance during mirror return. A common cause is the air damper. Disassemble it, replace the old rubber pad and clean any residue. Make sure that all bias and helper springs that aid the mirror return are properly in place. Clean all relevant pivots.

When evaluating the mirror return with the camera disassembled, make sure that it still latches during a "slow" return. Rather than letting the mirror snap back at the normal speed, control the speed of the return, and only let it go at the end of its travel. If it still latches with no momentum behind it, it should work properly in the fully assembled camera.

The self-timer is wound and released but it won't complete its cycle. It stops part of the way back and won't trigger the shutter.

The clockwork mechanism of the self-timer is dirty and needs to be cleaned. Do not force the timer to complete its cycle. It is located on the backside of the front plate and can be removed with two screws. To clean it, soak in isopropyl alcohol and/or use an ultrasonic cleaner. Disassembly of the unit is not usually required.

The mode dial is set to 'Auto', the camera won't enter auto exposure mode.

The mode dial communicates its position to the camera electronics through a set of contacts between the top cover and the camera body. The contacts may be dirty, oxidized, or misshapen. Clean the body-side and cover-side contacts.

When the mode dial is set to 'M', the shutter speed adjustment buttons don't change the selected speed in the viewfinder.

The button contacts are located in the top cover. Remove the top cover and disassemble the mode dial and button housing. Clean the button contacts.

The button presses are communicated to the camera electronics through a set of contacts between the top cover and the camera body. The contacts may be dirty, oxidized, or misshapen. Clean the body-side and cover-side contacts.