M7 Power Failure, battery contact not springing back

[Joe Cunningham]

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After much reading here I learned that when inserting batteries into the M7, the unreachable upper contact (neg) should spring back when batteries are pressed against it. Mine no longer do (I assume they used to, because the camera used to work). Putting batteries in the camera and turning it on does nothing. No red in the viewfinder display and the only speeds that trigger the shutter are 60 and 125 (the mechanical ones). Is there a known cause for the failure of the springback of the negative contact, and is there known fix that does not involve taking it in for repair? Also, I don't know what that contact looks like so if something is missing I'd miss that. When I shine a light into the battery well I see two parallel metallic lines spaced slightly apart. I assume those are the contact points that are not springing back, but that is an assumtion on my part.

Edited January 9, 2024 by Joe Cunningham
added final thee sentences

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[jrh68uk]

Just checked mine and what you describe isn't the case. Perhaps they made changes later on but in mine the top connectors do not move or spring at all; the springiness is provided by the sprung tab at the bottom which is easy to see. It's black, on the bottom of the battery chamber right near the "+" sign of the battery symbol. Then, just to the side of that is the meta connector that connects with the + of the bottom battery, on its side rather than its base. When the door is attached it pushes the bottom battery against both the bottom spring (to force both batteries upwards and so make contact with the -ve terminal any the top) and against the bottom + terminal. 

Is that bottom part still poking upward and able to provide spring to the base of the bottom battery when the door is re-attached? Have you checked the adjacent + terminal to see if there's any corrosion or anything that might prevent proper contact? 

[Clook]

My M7 with 2946*** serial is as described by Jason above.  There is a small black sprung tab at the bottom of the compartment.  The terminal at the top is not sprung.

[williamj]

On 1/10/2024 at 9:16 AM, Joe Cunningham said:

After much reading here I learned that when inserting batteries into the M7, the unreachable upper contact (neg) should spring back when batteries are pressed against it. Mine no longer do (I assume they used to, because the camera used to work). Putting batteries in the camera and turning it on does nothing. No red in the viewfinder display and the only speeds that trigger the shutter are 60 and 125 (the mechanical ones). Is there a known cause for the failure of the springback of the negative contact, and is there known fix that does not involve taking it in for repair? Also, I don't know what that contact looks like so if something is missing I'd miss that. When I shine a light into the battery well I see two parallel metallic lines spaced slightly apart. I assume those are the contact points that are not springing back, but that is an assumtion on my part.

From the comments so far it sounds like you may need to post a photo if that’s possible. Cheers. 

[Joe Cunningham]

On 1/13/2024 at 8:01 AM, jrh68uk said:

Just checked mine and what you describe isn't the case. Perhaps they made changes later on but in mine the top connectors do not move or spring at all; the springiness is provided by the sprung tab at the bottom which is easy to see. It's black, on the bottom of the battery chamber right near the "+" sign of the battery symbol. Then, just to the side of that is the meta connector that connects with the + of the bottom battery, on its side rather than its base. When the door is attached it pushes the bottom battery against both the bottom spring (to force both batteries upwards and so make contact with the -ve terminal any the top) and against the bottom + terminal. 

Is that bottom part still poking upward and able to provide spring to the base of the bottom battery when the door is re-attached? Have you checked the adjacent + terminal to see if there's any corrosion or anything that might prevent proper contact? 

Yes, the batteries once inserted do want to escape a bit due to tension from the lower spring you mentioned, and they sit nice and tight when inline and covered again. Just no power when I flick the switch. This thread was a bid to determine if what I had read elsewhere here about the unreachable upper contact also being spring loaded was true or not. Clook reprorts it is not (mine is not, and therefore according to Clook, normal). There is no visible corrosion, and yes I used new batteries. Does anyone know of any common reason for a complete power failure that the user can address, before I send it off for repair? 

[Clook]

Joe, I had another close look to double check.  Aside from the small sprung tab almost covering the + marker there is also a tab with two small connectors which is sprung horizontally so that the connectors push against the side casing on the bottom battery.  Double check this one also, it should move and resist light force eg pushing a matchstick onto it.  I have no technical knowledge but if everything at the battery end looks ok my next thoughts would be directed at the on/off switch or film advance...over to the experts I'm afraid as far as I'm concerned.