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Stuck Pentax Spotmatic Battery Cover

Stuck Pentax Spotmatic Battery Cover

Many times, customers would bring in cameras with the battery covers almost welded to the bottom cover from battery corrosion.
If you don’t know why this happens let me explain.
First you need to know the battery cover and bottom cover are made of brass with a brush silver colored plated finish. The battery cover has 2 small holes in the coin slot that are there to vent the gases produced as the battery generates electricity.
The holes in the battery cover are not for a tool or spanner wrench.  The slot in the cover measures 1.89mm wide and a Nickle will fit the slot just fine.


Pentax made a tool to remove these battery covers, part# 231K-A35-A.

I tried several methods to remove Spotmatic battery covers when they seemed permanently attached to the bottom cover.
When the tool you are using to remove the battery cover slips out of the slot, the tool rounds the edges of the battery cover. Rounding the edges makes it much more difficult to remove the cover. But the battery cover you have is the only one you have.

What not to try.

  • heating the cover.  There is a metal contact and a plastic insulator in the battery compartment assembly. The compartment assembly is spot welded to the cover.

This worked for many covers.

  1. Household vinegar attacks camera battery corrosion with a vengeance. I would remove the cover from the camera and place it in a glass dish. Pour in enough vinegar to immerse the bottom cover and let it soak for 24 hours. Any bubbles appearing mean the vinegar is reacting to the corrosion.
  2. The same as #1 with the addition of placing the dish in an ultrasonic cleaner for 3 x 30minute cleaning sessions and more additional soaking time.
  3. After thoroughly drying the cover inside and out. I then immersed the cover in an “over-the-counter” corrosion removal product like solution in the Liquid Wrench, PB Blaster, WD40, and other similar products. Sometimes soaking for days or several sessions in the ultrasonic cleaner and soaking again.
  4. If no amount a torque* on a good battery cover will remove it after all of the above… I replaced the cover set with a new or different parts

Lastly, I know I had covers in solutions for weeks to no avail.
Stuck Pentax Spotmatic Battery Cover

If some of you find this interesting. Please comment.


I started working on Pentax cameras in the 70’s. Pentax was kind of a hometown company at the time. Their cameras were very popular in the Colorado. Honeywell Corp, in Englewood was the importer at that time. Shared the same building with Rollei of America. Later Rollei closed and Pentax USA was formed and moved to the Inverness Dr business park in Englewood.

Many times, customers would bring in cameras with the battery covers almost welded to the bottom cover from battery corrosion.

1970’s film cameras are popular again?


About Gray

As a veteran attending National Camera's resident camera repair school in 1979, is where I found my true calling for the demanding yet extremely interesting field of photo equipment service and sales. For 25 years we grew every year. The staff and I serviced tens of thousands of film camera items, trained many technicians, met thousands of wonderful customers and truly had a fantastic time. Within 2 years of 2004, my service experience was devalued somewhat by the internet, film camera sales/service flatlined. Camera stores 50 times larger than mine were closing. I could see a new opportunity on the Internet. USCamera started as information site then became a family run internet business. Our mission remains the same, • Specialize in Vintage film equipment, mostly after 1958 • Knowledgeable • Provide quality products • Superior Service • Always available via phone - contact form – email All of us at USCamera look forward to serving you. Gray

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