Asahi Pentax Spotmeter battery compartment

[cakemuffin]

135652

I have this old Asahi Pentax Spotmeter, and this is how the inside looks like. Can somebody with the same model upload a photo of theirs?

It works, but requires fiddling with the metal tongue very often. I am wondering whether it's missing a piece...

[HMG]

There were at least a couple of versions of the analog (needle) Pentax Spotmeter. The earlier version ("1/21") used a 9v battery. The later version used button cells. Yours looks like the 1/21 version. Is that correct?

[cakemuffin]

Yeah mine has a 9v battery.

[OKAROB]

135800 Interesting photo, does your meter use two batteries or one. Mine uses a 9v plus some odd mercury button battery for which I have not figured out a solution for. Here is a picture of mine. Il looks like you are missing a spring that keeps the battery hatch closed. its just a tiny spring to keep the hatch door lock in the closed position. The bigger problem I had was the contact for the mercury battery in the door. It was suppose to make contact with a metal strip when the door is closed. If you bent the little flipper/contact too straight it would not allow the door to close or if it was bent too much it would not make contact at all. Hope the photo helps you.

[Don Barton]

I have had a 1/21 since purchasing it new in Japan. OKAROB is correct about the spring. The mercury battery was a PX-640. There is an alkaline replacement. I am reasonably sure the PX-640 supplies reference voltage, so you may need to tweak ISO setting. I had my meter repaired and calibrated by Quality Light Metric in 2001 and it works fine with the alkaline.

Don

[cakemuffin]

135800 Interesting photo, does your meter use two batteries or one. Mine uses a 9v plus some odd mercury button battery for which I have not figured out a solution for. Here is a picture of mine. Il looks like you are missing a spring that keeps the battery hatch closed. its just a tiny spring to keep the hatch door lock in the closed position. The bigger problem I had was the contact for the mercury battery in the door. It was suppose to make contact with a metal strip when the door is closed. If you bent the little flipper/contact too straight it would not allow the door to close or if it was bent too much it would not make contact at all. Hope the photo helps you.

Thank you for the photo, that is exactly what I was looking for. Now I know what's missing.

And indeed, that is also exactly the problem I have. The contact for the mercury battery in the door. It requires fiddling with almost every time I want to use it. Do you have any idea if it's just fiddly or whether we are missing another piece?


I have had a 1/21 since purchasing it new in Japan. OKAROB is correct about the spring. The mercury battery was a PX-640. There is an alkaline replacement. I am reasonably sure the PX-640 supplies reference voltage, so you may need to tweak ISO setting. I had my meter repaired and calibrated by Quality Light Metric in 2001 and it works fine with the alkaline.

Sounds like I'll have to live with it then. I'm using one (1) Wein Cell MRB625 and a small piece of wood with some wires to bridge the gap. It seems to work OK, but I haven't had it calibrated or anything.

Really appreciate the help!