Pentax MX battery drain

mollyclare · Feb 11, 2018

Hi,
I recently purchased a pentax MX from eBay. I am very new to film photography and this is my first 35mm camera (or camera in general). The camera is obviously quite old and does not function 100% (self timer leaver is broken, some minor dents or rust). The seller also mentioned that he suspected there was a short since the batteries drain quickly. He sent two lithium batteries with the camera that were not new but when i tried them they did not work so i brought some brand new. They worked and I take them out whenever the camera is not in use to prevent unnecessary battery drainage, so overall they have probably been used between 30 mins-an hour but today while I was taking a photo they seem to have died as the LED lights are very dim and it is stuck on the bottom light. Does anyone know what would cause battery loss so quickly and if there's any way I can fix this myself? Thank you!

trendland · Feb 11, 2018

You have to switch off your camera.
How does it work ? I did sell my Pentax MX 1980.........hard to remember.
It must be the exposure bottom.
You might try to switch it 90degree with the clockwise direction. Have a try or download a manual from the net.
Keyword : manual Pentax mx....
Good luck.

PS : If the exposure control switches of after 2 min. that might be also posible (real Bad remind about) the function might be failed.
With activated electronic exposure messurement (look at this little led's) the batteries should indeed get out of min.
voltage within 48 hours.
That is definitivly your problem.
If you can't solve it you can use your camera manualy it take out the batteries.

Chan Tran · Feb 11, 2018

I think it's the film advance level. If you push it plush with the body the meter turns off. But of course there could be a short that draws too much current when it's on because the OP removed the battery when not using

trendland · Feb 11, 2018

Chan Tran said:
I think it's the film advance level. If you push it plush with the body the meter turns off. But of course there could be a short that draws too much current when it's on because the OP removed the battery when not using

Ok - if that would happen there is a real electronic malfunction.
(If the batteries gets off after just one shooting - 1 - 3 hours) the batterie live
normaly is min. 1 year.

trendland · Feb 11, 2018

Chan Tran said:
I think it's the film advance level. If you push it plush with the body the meter turns off. But of course there could be a short that draws too much current when it's on because the OP removed the battery when not using

But you are right I remember it has to be the film advance level - that is also the case with the LX.
With regards

Les Sarile · Feb 11, 2018

Just checked my MX's and the meter LEDs will light as soon as you half press the shutter button regardless of film advance. This is the same for the LX. Since the meter comes on only when the shutter is pressed, does the LEDs turn off when the shutter is released? Is there a chance the shutter is inadvertently pressed causing the batteries to drain sooner?
Other then that I would guess that there is a weak short somewhere. I haven't begun working on any of my cameras yet so I would recommend taking a peak under the bottom cover first and follow the wire from the battery to look for obvious signs.

AgX · Feb 11, 2018

Likely a internal circuit issue, but as others already hinted at it may by a stuck button. I once got this with another model where an accessory exposure-control button got stuck by grain of sand and thus the camera was constantly metering. So check if every button behaves as it should.

ronnies · Feb 12, 2018

The meter switch is at the very bottom of the release, just under the base plate. Take the base plate of and make sure the switch is disconnected when the shutter release isn't being pressed and the metering isn't locked on with the wind on lever.

Ronnie

GRHazelton · Feb 12, 2018

I have this problem with my MXs. The oldest one, bought used some 20 years ago, worked flawlessly for many years, cell life was a year or more. Then for no apparent reason it began to "eat" cells. I left it with an Atlanta area repair shop, urging them to keep it long enough to see if their fix was "good." They returned it within 3 weeks; the drain remained. Back to them under their "warranty," again I urged them to take some time. By then I had my LX. Still the problem persisted.

I ran across a suggestion that a tiny switch under the base plate wasn't opening fully. I checked with a digital VOM, it was fine. This suggests a problem in the circuit board. No territory for me! I now have another MX, in gorgeous black, with the same problem. Time for a trip to Eric, I guess....

Eric Rose · Feb 12, 2018

I found I had to keep the lens cover on when I wasn't using it.

shutterfinger · Feb 12, 2018

Download a copy of the factory service manual here:
Dead Link Removed

Arvee · Feb 15, 2018

ronnies said:
The meter switch is at the very bottom of the release, just under the base plate. Take the base plate of and make sure the switch is disconnected when the shutter release isn't being pressed and the metering isn't locked on with the wind on lever.

Ronnie

This is the answer. Take off the bottom plate and actuate the shutter release button noting the mechanism that actuates the meter switch. There is a very simple set of brass contacts that are adjustable and, over time, the adjustment changes and the meter stays on all the time. IIRC, the adjustment screw is a tiny Phillips in an oval slot and you need to loosen it and reset it so the meter only comes on when the shutter release is pushed. It really is a simple adjustment. Fixed my MX in about 5 minutes.

Andrew K · Feb 15, 2018

ronnies said:
The meter switch is at the very bottom of the release, just under the base plate. Take the base plate of and make sure the switch is disconnected when the shutter release isn't being pressed and the metering isn't locked on with the wind on lever.

Ronnie

Being a Canon camera technician I only repaired a few MX's over the years, but this was always a very common problem with them. I can recall installing small pieces of rubber onto the edges of the switch to prevent them staying closed...

Les Sarile · Feb 16, 2018

The OP hasn't confirmed if the LEDs stay on.

eatfrog · Feb 16, 2018

I have the same problem.. Led does not stay on, i have checked the switch beneath the bottom plate, problem is not there.. Used to work just fine for many many years, then this problem started to happen. It eats through a pair of batteries in a matter of days.

GRHazelton · Feb 16, 2018

Fred Aspen said:
This is the answer. Take off the bottom plate and actuate the shutter release button noting the mechanism that actuates the meter switch. There is a very simple set of brass contacts that are adjustable and, over time, the adjustment changes and the meter stays on all the time. IIRC, the adjustment screw is a tiny Phillips in an oval slot and you need to loosen it and reset it so the meter only comes on when the shutter release is pushed. It really is a simple adjustment. Fixed my MX in about 5 minutes.

I'm glad it worked for you, but as I noted in an earlier post, it didn't work for me. Anyone have any other ideas?

GRHazelton · Feb 16, 2018

While we're discussing the MX, Pentax dropped the ball with the winder, IMHO, at least with the closure of the battery compartment. A tiny screw with a little thumbwheel threads into the plastic body of the winder. Every time I change the cells I dread the inevitable stripping of those threads. The winder for the ME cameras uses a recessed slide to open the battery compartment, a much more reliable method. Anyone strip the threads on the MX winder? If so how did you fix it?

trendland · Feb 16, 2018

GRHazelton said:
I'm glad it worked for you, but as I noted in an earlier post, it didn't work for me. Anyone have any other ideas?

The best idea is to buy a second mx.Hope you will find a normal used cheap model. That might be not the worst idea - think about : These cameras become higher and higher prices in used condition and they become not better from that age. The right time to buy a cheap mx in best condition with just 60bucks or a "used" LX at about $125,- (good working condition,technical ok) has ended. And prices will increase more and more. I have a me-super,mg, super A
all second hand to some bucks.But meanwhile no one is working (shutter problems) that seams to be the problem with all of that 40years aged models.
By the time my LX I checked yesterday has electronic problems with electronic times : 1/30,1/15,1/8 a.s.o.
But I could manage it to weak up the long times.
The worst case with mx, LX is to let them sleep for a while. You have to use it.
And some kind of "malfunction" seams to be normal with ALL pentax mx and most pentax LX.
The electronic of that period did not reach the year 2018 and Pentax didn't had any ideas in 1977 to make a design for that long livetime.
with regards

with regards

PS : Pentax/Riccoh has also no idea to bring out such models again.
PPS : 2004 I visited a professional camera dealer in Paris.He had just some mx cameras in good condition/hight priced but not a single one in "mint".
Suddenly he opened his camera storage :
P30 models (I don't like) - but it was a real
"Army of Pentax P30" - more than 60!!
Dealers "hamster" such cameras to sell them later for over 100bucks
(....not with P30

)

Pentax MX battery drain

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