Pentax ME: exposure problem, OVER led always on

viscard · 09-22-2022, 01:19 PM

I recently bought a Pentax ME (not the Super) that was stopped for about 20 years, and I identified a problem, with new batteries, in automatic mode, when I lightly press the shutter button, the red LED next to the OVER lights up on the display, no no matter which ASA is set or which aperture is selected, the LED is always on OVER, and if I release the shutter the mirror locks. I don't know if it could be a problem with the electronics because the LED lights up, so power is coming. I'm suspicious of the exposure compensation dial, it behaves in an unconventional way for cameras, when I turn it sometimes it doesn't "stop" at the "1x, 2x, 4x" markings, only sometimes it "stops", it doesn't seem to be perfectly assembled, showing these two different behaviors.
Another possibility would be an oxidation on the dial, maybe spraying contact cleaner would help?
Pentax ME owners have had a similar problem, could you help me?

Not a Number · 09-22-2022, 03:22 PM

You could try checking the service manual if it mentions the problems. There could be a fault somewhere in the system even if the lights come on.

A contact cleaner might make the problem worse unless you use one that is made for moving contacts or the surface lubrication would get removed.

Service manual can be downloaded here:
https://www.pentax-manuals.com/manuals/service/servicemanuals.htm

viscard · 09-22-2022, 05:40 PM

Originally posted by Not a Number

You could try checking the service manual if it mentions the problems. There could be a fault somewhere in the system even if the lights come on.

A contact cleaner might make the problem worse unless you use one that is made for moving contacts or the surface lubrication would get removed.

Service manual can be downloaded here:
https://www.pentax-manuals.com/manuals/service/servicemanuals.htm

Thanks for the link to the manual, I'll check it out.
I found a video on youtube (

Youtu.be

) where he seems to have the same problem as me, fixed exposure in OVER, and the cause seems to be in the dial itself, mounted wrongly or pasted due to time without use. I don't have the tools needed to make the repair, I'll have to send it to a technician and maybe indicate the possible problem.
Anyway, if anyone had the same problem and knows the solution, I'd be grateful if you could share your experience.

reh321 · 09-22-2022, 06:29 PM

Originally posted by viscard

I recently bought a Pentax ME (not the Super) that was stopped for about 20 years, and I identified a problem, with new batteries, in automatic mode, when I lightly press the shutter button, the red LED next to the OVER lights up on the display, no no matter which ASA is set or which aperture is selected, the LED is always on OVER, and if I release the shutter the mirror locks. I don't know if it could be a problem with the electronics because the LED lights up, so power is coming. I'm suspicious of the exposure compensation dial, it behaves in an unconventional way for cameras, when I turn it sometimes it doesn't "stop" at the "1x, 2x, 4x" markings, only sometimes it "stops", it doesn't seem to be perfectly assembled, showing these two different behaviors.
Another possibility would be an oxidation on the dial, maybe spraying contact cleaner would help?
Pentax ME owners have had a similar problem, could you help me?

By ‘automatic mode’, you mean when the camera body is supposed to set the shutter speed?
What happens if you select the shutter speed?

viscard · 09-22-2022, 07:51 PM

Originally posted by reh321

By ‘automatic mode’, you mean when the camera body is supposed to set the shutter speed?
What happens if you select the shutter speed?

The Pentax ME does not have a manual mode, there is an "AUTO" option where I set the aperture and the camera determines the speed, and there is a flash sync option where the camera shoots at 1/100, but without any photometer aid , in this mode my camera shoots normally.

Wheatfield · 09-23-2022, 07:08 AM

Originally posted by viscard

Thanks for the link to the manual, I'll check it out.
I found a video on youtube (https://youtu.be/elvrysdJ18w) where he seems to have the same problem as me, fixed exposure in OVER, and the cause seems to be in the dial itself, mounted wrongly or pasted due to time without use. I don't have the tools needed to make the repair, I'll have to send it to a technician and maybe indicate the possible problem.
Anyway, if anyone had the same problem and knows the solution, I'd be grateful if you could share your experience.

The ISO and aperture cam follower resistors are prone to corrosion on all the Pentax cameras from that era.
Try this: Hold down the ISO adjuster lock and quickly rotate the ISO dial from lock to lock about 50 times. Do the same with the aperture cam lever inside the mirror box. With luck that will scrape off any corrosion that has accumulated and return the camera to normal operation.

viscard · 09-23-2022, 11:48 AM

Originally posted by Wheatfield

The ISO and aperture cam follower resistors are prone to corrosion on all the Pentax cameras from that era.
Try this: Hold down the ISO adjuster lock and quickly rotate the ISO dial from lock to lock about 50 times. Do the same with the aperture cam lever inside the mirror box. With luck that will scrape off any corrosion that has accumulated and return the camera to normal operation.

I tried this way, and it didn't work, I believe that the oxidation stuck the metallic disc that makes the contact. I will take the camera to a trusted technician. My fear is that the camera is doomed, not having a concert, but from the video I mentioned, he had the same problem and managed to fix it with some ease.

09-22-2022, 01:19 PM	#1
viscard New Member Join Date: Sep 2022 Posts: 4	Pentax ME: exposure problem, OVER led always on I recently bought a Pentax ME (not the Super) that was stopped for about 20 years, and I identified a problem, with new batteries, in automatic mode, when I lightly press the shutter button, the red LED next to the OVER lights up on the display, no no matter which ASA is set or which aperture is selected, the LED is always on OVER, and if I release the shutter the mirror locks. I don't know if it could be a problem with the electronics because the LED lights up, so power is coming. I'm suspicious of the exposure compensation dial, it behaves in an unconventional way for cameras, when I turn it sometimes it doesn't "stop" at the "1x, 2x, 4x" markings, only sometimes it "stops", it doesn't seem to be perfectly assembled, showing these two different behaviors. Another possibility would be an oxidation on the dial, maybe spraying contact cleaner would help? Pentax ME owners have had a similar problem, could you help me?

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09-22-2022, 03:22 PM	#2
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	You could try checking the service manual if it mentions the problems. There could be a fault somewhere in the system even if the lights come on. A contact cleaner might make the problem worse unless you use one that is made for moving contacts or the surface lubrication would get removed. Service manual can be downloaded here: https://www.pentax-manuals.com/manuals/service/servicemanuals.htm

09-22-2022, 06:29 PM	#4
reh321 Pentaxian Join Date: Nov 2014 Location: South Bend, IN, USA Photos: Gallery \| Albums Posts: 23,185	Originally posted by viscard I recently bought a Pentax ME (not the Super) that was stopped for about 20 years, and I identified a problem, with new batteries, in automatic mode, when I lightly press the shutter button, the red LED next to the OVER lights up on the display, no no matter which ASA is set or which aperture is selected, the LED is always on OVER, and if I release the shutter the mirror locks. I don't know if it could be a problem with the electronics because the LED lights up, so power is coming. I'm suspicious of the exposure compensation dial, it behaves in an unconventional way for cameras, when I turn it sometimes it doesn't "stop" at the "1x, 2x, 4x" markings, only sometimes it "stops", it doesn't seem to be perfectly assembled, showing these two different behaviors. Another possibility would be an oxidation on the dial, maybe spraying contact cleaner would help? Pentax ME owners have had a similar problem, could you help me? By ‘automatic mode’, you mean when the camera body is supposed to set the shutter speed? What happens if you select the shutter speed?

09-22-2022, 07:51 PM	#5
viscard New Member Join Date: Sep 2022 Posts: 4 Original Poster	Originally posted by reh321 By ‘automatic mode’, you mean when the camera body is supposed to set the shutter speed? What happens if you select the shutter speed? The Pentax ME does not have a manual mode, there is an "AUTO" option where I set the aperture and the camera determines the speed, and there is a flash sync option where the camera shoots at 1/100, but without any photometer aid , in this mode my camera shoots normally.

09-23-2022, 07:08 AM	#6
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,991	Originally posted by viscard Thanks for the link to the manual, I'll check it out. I found a video on youtube (https://youtu.be/elvrysdJ18w) where he seems to have the same problem as me, fixed exposure in OVER, and the cause seems to be in the dial itself, mounted wrongly or pasted due to time without use. I don't have the tools needed to make the repair, I'll have to send it to a technician and maybe indicate the possible problem. Anyway, if anyone had the same problem and knows the solution, I'd be grateful if you could share your experience. The ISO and aperture cam follower resistors are prone to corrosion on all the Pentax cameras from that era. Try this: Hold down the ISO adjuster lock and quickly rotate the ISO dial from lock to lock about 50 times. Do the same with the aperture cam lever inside the mirror box. With luck that will scrape off any corrosion that has accumulated and return the camera to normal operation.

09-23-2022, 11:48 AM	#7
viscard New Member Join Date: Sep 2022 Posts: 4 Original Poster	Originally posted by Wheatfield The ISO and aperture cam follower resistors are prone to corrosion on all the Pentax cameras from that era. Try this: Hold down the ISO adjuster lock and quickly rotate the ISO dial from lock to lock about 50 times. Do the same with the aperture cam lever inside the mirror box. With luck that will scrape off any corrosion that has accumulated and return the camera to normal operation. I tried this way, and it didn't work, I believe that the oxidation stuck the metallic disc that makes the contact. I will take the camera to a trusted technician. My fear is that the camera is doomed, not having a concert, but from the video I mentioned, he had the same problem and managed to fix it with some ease.