pentax sp500 slr

[Mauro]

Dear friends, I've just received a wonderful gift....Asahi Pentax SP500 with a Tokina 70-210 f3.5!
The camera works perfectly but I'm experiencing a problem with the battery cap: an old battery is still inside and I fear that chemicals leaked and glued the cap to the bottom plate. I can't open the cap to replace the battery..what can I do?
Any advice is much appreciated, thanks.

 

[Tom hicks]

you might try taking the bottom plate off carefully so as not to damage the wires going to the battery.

 

[Pioneer]

I had a Pentax Spottie with the same issue. I applied very small amounts of vinegar around the edge of the cap, left it sit for a day, then applied some more. Every day I tested the cap until it finally moved and unscrewed. A little more vinegar and the battery came out. I was able to clean the inside of the battery compartment until a new battery would work.

In my case the wires inside were still attached. There are circumstances where you may need to remove the bottom cover, clean things up and then reattach a wire or two.

But patience and the judicious application of mild acids to clean the battery leakage and eventually it will clean back up again.

Of course, the neat thing about these old cameras is that they are very usable without the meter.

 

[Mike Fish]

Once you get in - and get it cleaned up, an Energizer E387S is an exact fit replacement. The original was a 1.35v mercury cell. The E387S is 1.55v. But the Pentax meter circuit has voltage regulating bridge circuitry, so the voltage difference is not an issue. With some cameras the voltage difference matters, with this one it doesn't.

I ran the 387 in a SP1000 I recently had and it worked great.

Dear friends, I've just received a wonderful gift....Asahi Pentax SP500 with a Tokina 70-210 f3.5!
The camera works perfectly but I'm experiencing a problem with the battery cap: an old battery is still inside and I fear that chemicals leaked and glued the cap to the bottom plate. I can't open the cap to replace the battery..what can I do?
Any advice is much appreciated, thanks.

 

[Ranchu]

You can take the bottom off to make it a little easier to handle. The battery compartment is attached to it, but you can soak the whole thing in vinegar.

 

[charjohncarter]

I had a Pentax Spottie with the same issue. I applied very small amounts of vinegar around the edge of the cap, left it sit for a day, then applied some more. Every day I tested the cap until it finally moved and unscrewed. A little more vinegar and the battery came out. I was able to clean the inside of the battery compartment until a new battery would work.

In my case the wires inside were still attached. There are circumstances where you may need to remove the bottom cover, clean things up and then reattach a wire or two.

But patience and the judicious application of mild acids to clean the battery leakage and eventually it will clean back up again.

Of course, the neat thing about these old cameras is that they are very usable without the meter.

Same thing with my Spotmatic, give this a try. Go slow but consistent daily application.

 

[JP Owens]

It may not be a leaky battery. The Pentax cameras had very shallow threads on the battery cover that were easy to cross thread if you weren't very careful. As many have pointed out, it is easier to deal with you take the bottom off.

 

[Dwig]

It may not be a leaky battery. The Pentax cameras had very shallow threads on the battery cover that were easy to cross thread if you weren't very careful. As many have pointed out, it is easier to deal with you take the bottom off.

+1, but it is much more likely that it is a corroded battery.

@OP: remove the baseplate if you can. Note that the outside end pair of screws are different than the pair near the tripod socket. Don't mix them up. Soak the seam around the battery cap with a trace of acetic acid (white distilled vinegar or photographic stop bath) and repeat after 5 to 10 min. Use a mint condition US nickel, or similar coin that fits extremely well, held in a pair of locking pliers (ViseGrip, ...) as the tool to turn the cap. Once open, wipe out the battery compartment carefully but don't use any abrasive as you can easily damage the plating and cause chronic connection problems.

 

[Mauro]

Dear Friends,
thans to your help I have been able to remove the battery cap: the bottom plate has been soaked in vinegar for 5 hours as per your advices, and it worked well. I have replaced the old mercury battery with a new LR41 with a rubber o-ring to compensate the diameter difference. It seems that the lightmeter is overexposing a bit: but I will test its accuracy soon.
By the way the camera is a great juwel: my first roll is dedicated to you all!

Ciao!!!