Vivitar 400/SL meter woes - am I missing something???

[xkaes]

Yet another M42 camera has landed in my lap -- this one with a problem, the TTL meter.

The camera came with the manual, but the CdS meter doesn't respond as it should. It might be dead, but I thought I'll ask for opinions.

It's a typical, simple system. You dial in the ISO and select a shutter speed. Both of these mechanically adjust the needle in the viewfinder - as they should. When I press the shutter release half-way, it stops down the lens to the set aperture and takes a meter reading. The needle should move on it's own, at that point. But despite the lens stopping down, the needle does not respond -- or change at all as the f-stop is adjusted.

I have the correct battery (it works fine in other cameras) -- and the contacts in the battery chamber are nice and clean.

There is no function in the camera to test the electrical system -- other than the needle responding to a change in the aperture -- which it doesn't.

I can't think of anything else to try. Can you? CdS meters are usually pretty bullet-proof except for battery corrosion -- and I see no evidence of that.

 

[ic-racer]

Check all the contact switches in the meter path.’ Is it just one or are there others?

Rollei SL35M Meter Switching Repair

Rollei SL35M has a curious series of micro switches to aid in backwards compatibility with NON-OPEN APERTURE metering using the SINGLE-PIN Rollei lenses. The idea is that when a lens is removed the meter will turn off. If an OPEN-APERTURE lens (so called two-pin lens) is attached, the meter...

www.photrio.com

 

[Nicholas Lindan]

You say the shutter speed/asa dial causes the needle to move - which implies the meter movement, the meter on/off switch and at least some of the wiring do work. Can you center the needle using the shutter speed dial? I ask as this gives an indication of the state of the CdS arm of the metering "bridge circuit."

CdS cells do go bad if moisture gets to the element. You may or may not be able to find a replacement that fits.

 

[xkaes]

As with many other cameras, even with the meter OFF, changing the ISO or the shutter speed moves the needle -- mechanically. The only time the needle moves electronically is when it is turned ON by pressing the shutter release half-way -- which stops down the lens -- and by changing the f-stop, the needle will match the right spot, as the light through the lens changes.

On this camera, the needle moving as the ISO or shutter speed are changed does not indicated that the meter is working -- because that happens when the meter is OFF. It indicated that the mechanical functions of the metering system are working correctly. It's the electrical part that I'm having a problem with.

 

[xkaes]

Check all the contact switches in the meter path.’ Is it just one or are there others?

I was hoping for a possible solution without surgery.

 

[xkaes]

I finally got around to looking at this camera again -- maybe just to give me a new idea. I hadn't done anything to it, but today I picked it up, selected a shutter speed, pressed the shutter release halfway, the aperture stopped down -- AND the meter needle moves correctly, as it should as I change the f-stop. Best think of all, it's accurate.

Stranger things have happened.