Rolleiflex 3.5F Meter SHOULD work but....

Both the selenium cell and contacts inside where the cell is inserted register over 60 OHMs on a multimeter. So, theoritically the meter should work. However, there is no meter movement when a flash light is shined into the exposure cell, or when I place my hand over it.

Any suggestions?

Check the voltage of the selenium cell first. You'll need to expose it to bright sunlight or up close to a 75-100W light bulb. The voltage should be at least 0.2-0.3 volts

Check for continuity (use ohms scale) from the selenium cell to the ends of the wires. If the wires are soldered to the cell, there should be no problem with continuity

If the wires are only contacting the cell by "spring" pressure, you will have a problem, you'll need to clean the wires and surfaces thoroughly for the wires to make good electrical contact

If the cell and wiring pass electrical current and the needle still doesn't move, you may have an open circuit in the armature that the needle is attached to or the armature is stuck somehow

Just push the needle with a toothpick to see if it's free to move, and check how much slop there is in the armature bearings. There should be an adjusting screw on top but you need to know what you're doing to adjust it

Check the voltage of the selenium cell first. You'll need to expose it to bright sunlight or up close to a 75-100W light bulb. The voltage should be at least 0.2-0.3 volts

 

Check for continuity (use ohms scale) from the selenium cell to the ends of the wires. If the wires are soldered to the cell, there should be no problem with continuity

 

If the wires are only contacting the cell by "spring" pressure, you will have a problem, you'll need to clean the wires and surfaces thoroughly for the wires to make good electrical contact

 

If the cell and wiring pass electrical current and the needle still doesn't move, you may have an open circuit in the armature that the needle is attached to or the armature is stuck somehow

 

Just push the needle with a toothpick to see if it's free to move, and check how much slop there is in the armature bearings. There should be an adjusting screw on top but you need to know what you're doing to adjust it

I checked the contacts on the back of the selenium cell and the contacts inside where those "pins" would go before posting and both registered over 60 OHMs. The needle with the circle on the tip does move when I make adustments with the knobs but not with light shined into the exposure cell on front or when I put my hand over it. The other needle moves freely when I nudge it with a toothpick. I have repeatedly tried the exposure meter adjustment instructions in the manual but have not had any results. This includes using the adjustment screw on the back. Should the needle without the circle on the end touch the edge of the red "marker"? Right now it does not. It stays about 1/4 inch from it.

Are you saying I need to disassemble the selenium cell?

It seems you have a worn out selenium cell or bad contacts or both. There are other components that can become faulty as well

This link may help you to understand more about the meter

rolleiflex 3.5f -- light meter issue

You may have to send it out for repair, or simply start using a handheld meter

This link may be of assistance also

Rolleiflex 3.5F meter not working

A resistance or continuity test tells you nothing about the condition of the cell or meter. Dead or dying selenium cells that are 30 years old or more are the rule rather than the exception.

An on-camera reflection meter like that in the Rollei is unreliable anyway, even when properly working and calibrated. My advice would be not to waste your time or money on it, and to buy a handheld meter capable of incident measurement.

That's why I asked Ray to check the voltage of the cell first before proceeding to continuity checks. If the cell produces any less than 0.25Volts, it's underpowered

Selenium cells shouldn't be written off until their power is checked and are given a good visual inspection. They are painted with lacquer for moisture proofing and if the lacquer is still in good condition over the whole surface of the selenium, the cell is probably still producing adequate voltage. Kept well, they can last for many decades and then some

A Polaroid cell 59 years old. On the back of this cell there is printed "11/7/1959" - do the math and it's 59 years old. It's like new and would power your home, it's that powerful. I'm guessing, but this cell might even fit Ray's 3.5. If I had the dimensions of the Rolleiflex's cell, I'd know for sure if it would or wouldn't.

The number of non-working selenium meters that I encounter far outweighs the number of good ones, and even when they're 'working' the accuracy across the range is often questionable.

A simple voltage test also doesn't count for much; it's current that drives a mechanical moving-coil meter, not voltage. The way that most selenium cells go bad is to develop either a high internal resistance or partial short. This results in insufficient current being produced to drive the meter mechanism to full scale.

I've read of 'remedies' that involve baking the cell. However, given the toxicity of Selenium, I really wouldn't advise messing with the stuff. Not unless you're willing to risk chronic halitosis that smells like rotten cabbage!

I know what you mean Joe but that doesn't mean the meters can't be repaired

I cut a piece off the Polaroid cell to replace the crook cell (below) in my Metra. As you can see, the cell was encased in plastic which yellowed and aged, but the cell, made in 1958, still produced enough power to use again however the cell wasn't protected anymore so had to be replaced

Current is never a problem as long as the cell's voltage is right and the soldered joints are solid and corrosion free

Old Metra cell, as bad as it looks, was still producing 0.3volts in bright light

I know what you mean Joe but that doesn't mean the meters can't be repaired

 

I cut a piece off the Polaroid cell to replace the crook cell (below) in my Metra. As you can see, the cell was encased in plastic which yellowed and aged, but the cell, made in 1958, still produced enough power to use again however the cell wasn't protected anymore so had to be replaced

 

Current is never a problem as long as the cell's voltage is right and the soldered joints are solid and corrosion free

 

 

Old Metra cell, as bad as it looks, was still producing 0.3volts in bright light

 

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There is one place, in Germany, that at one time repaired them. Then there is Quality light metric. But I don't see websites for either. The email address I did find for QLM bounced back.

"Current is never a problem as long as the cell's voltage is right and the soldered joints are solid and corrosion free..."

- Yes it is! I've come across several meters where the cell voltage into a 10 Megohm DVM has been in excess of .5v in bright light. Yet when connected back up to their meter, they gave nothing like the deflection they should have done. Testing revealed nothing wrong with the meter, wiring or contacts.

You also need to be very careful with the MC meter mechanism if attempting DIY repair. A small particle of dust, or worse, magnetic metal swarf, can ruin a meter and be almost impossible to remove without dislodging the coil from its delicate pivots. The coil wire and its connections are also extremely fragile and a slip of a tool or finger can easily open-circuit the meter and render it beyond repair. Even if you manage to re-solder the coil wire, it affects the weight of the coil and any balance weights then need to be re-positioned to bring the meter back into dynamic stasis.

FWIW. Those cheap solar garden lights are a good source of silicon cells. These can pretty well replace a similar sized selenium cell directly.