[monkmonk]

Hello!
I just bought a second hand Pentax MX and the previous owner told me that the light meter was fine and working properly lol it doesn't work. (Well, not quite)
The exposure issue I'm having is that when I replaced the LR44 batteries to see if it worked, the LED did work, but in a fixed position with underexposure and only for a few seconds. After that I can't turn it back on, only if I let the camera rest for a while and try to turn it on again.
I was looking for a solution here, but only found problems related to the lower circuit being bent and not making good contact.
I checked it like 5 times with a tester and it works fine.
So imagine that the problem came from higher up, specifically from the upper circuit.
Then I opened the upper frame but I couldn't see anything that was burned or any circuit cut, since it was open I did a little cleaning.

Could someone tell me if they see something strange or have any idea what can happen and how I could solve it?
I attach some images of the circuit and a video so that the state of this can be seen well.
Images: Top circuit Pentax MX - Album on Imgur
Video: Top circuit Pentax MX - Video on Vimeo
Thanks in advance!

[FozzFoster]

I do not have the solution to this problem.
What I might provide is a service manual for the MX:
https://pentax-manuals.com/manuals/service/mx_sm.pdf

[builttospill]

Welcome to the forum. I love the MX.

Do you have a battery tester? Can you check the voltage on the batteries? Or you might try another set of batteries to make sure that's not the problem.

[texandrews]

The above suggestion to actually test the batteries is a good one. But my solution was a Gossen Luna Pro S with the Zone dial. An excellent solution, I might add....

[monkmonk]

I do not have the solution to this problem.
What I might provide is a service manual for the MX:
https://pentax-manuals.com/manuals/service/mx_sm.pdf

I had it but in very low quality, thanks for that one! ;D

Welcome to the forum. I love the MX.

Do you have a battery tester? Can you check the voltage on the batteries? Or you might try another set of batteries to make sure that's not the problem.

Yeah, did it, 3v total :/ I wish it were the batteries haha

The above suggestion to actually test the batteries is a good one. But my solution was a Gossen Luna Pro S with the Zone dial. An excellent solution, I might add....

Its a good solution, but i wanted a compact camera ;D

Thank you all for all! but finally I bought another camera body and the seller assures me that it works correctly, I hope this time it's true haha
And I will proceed to sell the old body to someone who does not mind that the exposure meter does not work once I verify that it works correctly.
Have a nice day people!

[Jonathan Mac]

The MX is a lovely camera but it's forty or more years old and doesn't have the most reliable meter. If the seller told you it works and it doesn't then you have grounds for a refund but I have manual cameras whose meters I don't trust at all but I shoot them using sunny-16 or an external meter. It depends if you want that level of automation and if you paid premium for a camera with a working light meter.