Auto Meter IV F unusual fault. Any ideas?

I have bought a Minolta Auto Meter IV F from an auction site. The

unit looks good and works, but I need to set the film speed on

one-tenth the real film speed to get correct readings. I've done lots

of tests, replaced battery, compared it to another Autometer IV F,...

 

I've read the manual, I've inspected it thoroughly, I've tried

removing the battery to "reset" the unit...

 

The vendor has ceased to be registered, and doesn't talk. The cost of

having something like this repaired here (Australia) makes that an

unattractive option.

 

If I'm using ISO=200 film, I set the meter on ISO=20, and seem to get

accurate results in Ambient and Non-Cord modes, which is all I need.

If further testing confirms its accuracy, I suppose I can live with it

being like this.

 

But does anyone have any idea why or how such a fault could occur?

The couple of Minolta Autometer samples I've had my hands on have been pretty inaccurate compared to meters I've know to be accurate.

I have available another Autometer IV F and it agrees with several other meters that I consider to be accurate. They all agree very closely with one another, anyway. The strange thing is that the meter in question is consistent and accurate IF i set it one one-tenth of the real ISO speed.

 

In other words, it reads about 3.3 stops too high, but appears to be quite consistent.

If your other meter is consistent with the others, you can adjust this one to agree with the rest. Just open the battery cover and look for the small plastic adjustment screw/knob and move it + or - according to the desired reading. Hope this helps.

 

Gary

Thanks Gary. I already thought of that, but it's only for small adjustments (+ or - 0.7 or so)

John,

 

This is a fairly common problem with this meter. It is the incident/reflected pin under the dome which is most likely causing grief. If it is not making proper contact (inside the head), it will cause erroneous readings. Fortunately, it's a pretty simply fix. You just remove the screws from the back of the head and you'll see two metal arms that (barely) contact eachother when pressing the metal pin under the dome. It's just a matter of cleaning the contacts and bending one of the arms so as to make better contact with the other.

Rob, spot on! I cleaned it with some clean cotton fabric, then some aerosol contact cleaner, and now it agrees exactly with the other meters.

 

Thank you very much!

 

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