Spotmatic SP meter stays at + limit when switched on

Falkin · 10-29-2022, 10:34 PM

I just bought a Spotmatic which looks to be in generally good condition. While it's not essential, I'd like to have the meter working if possible. For now, I am using a SR927SW 1.55V, inserted with the + side inward to the camera, and a ring cut from heat shrink to insulate the sides of the battery.

The meter powers on, because the needle moves to the + position. Other than that, it doesn't react to changes in aperture, shutter speed, or ISO. Only switching to ISO 100/ B shutter speed drops the needle back to minimum. So far, I've only cleaned the contacts that I can easily access: bottom of the battery cover, the battery compartment thread, the contact tab for the + side of the battery, and the contact terminal of the battery compartment. In addition to that, the tab in the camera that makes contact with the battery compartment terminal. I used contact cleaner for all these.

What should I look at next? I realize it means going a bit deeper into the camera, and I'm sure this topic has been covered, but would appreciate any links to the best information on troubleshooting this.

Not a Number · 10-29-2022, 11:29 PM

Service manuals for the Spotmatics can be found online:
https://learncamerarepair.com/product.php?product=11

If the meter movement needs to be replaced the K1000 movement can be adjusted and modified for Spotmatics
Pentax 23704-J100 Meter Movement | K1000 Old | Spotmatic | USCamera

**arnold** · 10-30-2022, 12:05 AM

Yes, negative goes to the cap. Here is my list of batteries for the Sp (not SPF). Note they are not all full size. You can also use a hearing aid battery size 302
LR41,AG3, Vinnic S936S, SR 45, LR45, SR936S, SG9, AG9.
The LR41 size fits with a spacer. its size is 7.9x3.6
The normal battery size is 9.5x3.6

Falkin · 10-30-2022, 02:36 AM

Thanks for the information.

If I can get the meter working I would perhaps get the adapter that drops the voltage. I have handheld meters that I can use, so it's mainly bloodymindedness that makes me want to get the camera working with the metering it had originally. That simple TTL metering method is also what I had in my first SLR, so I enjoy that relatively bare bones way of taking photos.

10-29-2022, 10:34 PM	#1
Falkin New Member Join Date: Oct 2022 Posts: 9	Spotmatic SP meter stays at + limit when switched on I just bought a Spotmatic which looks to be in generally good condition. While it's not essential, I'd like to have the meter working if possible. For now, I am using a SR927SW 1.55V, inserted with the + side inward to the camera, and a ring cut from heat shrink to insulate the sides of the battery. The meter powers on, because the needle moves to the + position. Other than that, it doesn't react to changes in aperture, shutter speed, or ISO. Only switching to ISO 100/ B shutter speed drops the needle back to minimum. So far, I've only cleaned the contacts that I can easily access: bottom of the battery cover, the battery compartment thread, the contact tab for the + side of the battery, and the contact terminal of the battery compartment. In addition to that, the tab in the camera that makes contact with the battery compartment terminal. I used contact cleaner for all these. What should I look at next? I realize it means going a bit deeper into the camera, and I'm sure this topic has been covered, but would appreciate any links to the best information on troubleshooting this.

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10-29-2022, 11:29 PM	#2
Not a Number Moderator Join Date: Mar 2012 Location: Venice, CA Posts: 10,526	Service manuals for the Spotmatics can be found online: https://learncamerarepair.com/product.php?product=11 If the meter movement needs to be replaced the K1000 movement can be adjusted and modified for Spotmatics Pentax 23704-J100 Meter Movement \| K1000 Old \| Spotmatic \| USCamera

10-30-2022, 12:05 AM	#3
arnold Site Supporter Join Date: Aug 2012 Location: Queensland Photos: Gallery \| Albums Posts: 4,294	Yes, negative goes to the cap. Here is my list of batteries for the Sp (not SPF). Note they are not all full size. You can also use a hearing aid battery size 302 LR41,AG3, Vinnic S936S, SR 45, LR45, SR936S, SG9, AG9. The LR41 size fits with a spacer. its size is 7.9x3.6 The normal battery size is 9.5x3.6

10-30-2022, 02:36 AM	#4
Falkin New Member Join Date: Oct 2022 Posts: 9 Original Poster	Thanks for the information. If I can get the meter working I would perhaps get the adapter that drops the voltage. I have handheld meters that I can use, so it's mainly bloodymindedness that makes me want to get the camera working with the metering it had originally. That simple TTL metering method is also what I had in my first SLR, so I enjoy that relatively bare bones way of taking photos.