Gossen Luna Pro F meter: Battery check

Roy in Silver · Jan 4, 2017

Hello all and Happy New Year!
I have just acquired a Gossen Luna Pro F meter. The battery in it was dead so I got a new one, a Duracell MN 1604, 9V.
The meter is working and giving what appear to be accurate exposure measurements. However, when i perform the Battery Check the meter's needle kicks too high, being far outside the green band that is supposed to indicate the correct voltage range. The green band is labelled BATT, just to the right of the 0 centreline, in the image shown here.

Should I be worried about this? Is this something that anyone else here has encountered?
Thanks for any advice!
Roy

AgX · Jan 4, 2017

My first idea was that you did not perform a battery check but a light metering.
This could be the case if the battery-check switch does not work.

Leigh B · Jan 4, 2017

Hi Roy,

Here's the manual for you meter: http://www.butkus.org/chinon/flashes_meters/luna-pro_f/gossen_luna_pro_f.pdf

Read and follow the directions on page 5 for initial operation.

- Leigh

Arvee · Jan 4, 2017

Completely normal, mine does the same thing. My SBC does, however, stay in the green zone.

Leigh B · Jan 4, 2017

Meters that use batteries usually have an internal adjustment to set the battery scale.
Here's an annotated photo of the Luna Pro-F:
Dead Link Removed
Note the adjustment on the left labeled (1) Voltage Adjust.
Turn that with a small flat-blade screwdriver.

Here's a thread on Photo.Net about calibrating the meter:
http://photo.net/classic-cameras-forum/00RjvJ

- Leigh

Roy in Silver · Jan 4, 2017

AgX said:
My first idea was that you did not perform a battery check but a light metering.
This could be the case if the battery-check switch does not work.

I can understand why you would think that, particularly because the first of the two steps in performing the battery check does in fact do the same as a normal measurement.
Here is the relevant extract from the instructions in the user manual:
"Check the battery by pushing and releasing the power switch (4) and then pushing in and holding the battery test
button (16). The meter needle should be well within the battery test zone (12)." I followed these instructions precisely. The power switch press makes a light reading and displaces the needle accordingly: the pressing of the battery test button kicks the needle abruptly clockwise i.e. to the high end of the voltage range. The final needle position depends to some extent on its position before the pressing of the battery test button.

AgX · Jan 4, 2017

Printed circuit board photo is of the Luna Pro.

Leigh B · Jan 4, 2017

AgX said:
Photo is of the Luna Pro.

Tell that to Google.

- Leigh

Roy in Silver · Jan 4, 2017

Fred Aspen said:
Completely normal, mine does the same thing. My SBC does, however, stay in the green zone.

Thanks! That is reassuring.
I suspect some internal calibration of the battery voltage circuit would be needed to ensure proper operation of the battery check as described in the user manual. At the present time I really don't want to be opening the case up and trying to make the calibration myself.
I think in the future I shall gauge battery condition by observing the accuracy of the exposure measurements made, rather than trying to perform the battery check.

AgX · Jan 4, 2017

The double designation by Gossen/their US importer is a mess... (the Luna Pro F without that flash metering should be a Luna Pro, but that is a complete different meter...)

Roy in Silver · Jan 4, 2017

Leigh B said:
Meters that use batteries usually have an internal adjustment to set the battery scale.
Here's an annotated photo of the Luna Pro-F:
Dead Link Removed
Note the adjustment on the left labeled (1) Voltage Adjust.
Turn that with a small flat-blade screwdriver.

Here's a thread on Photo.Net about calibrating the meter:
http://photo.net/classic-cameras-forum/00RjvJ

- Leigh

Thanks, Leigh, but that is a different meter, as pointed out by
AgX.

Roy in Silver · Jan 4, 2017

AgX said:
Printed circuit board photo is of the Luna Pro.

Thanks for that AgX.

jimjm · Jan 4, 2017

Mine has always done the same thing. It lasted over 5 years with the same battery, and I only replaced it because I wasn't sure how old it REALLY was. Might have been 10 years old.

If I'm not going to use the meter for a few months or more, I take the battery out just in case it starts corroding when I'm not looking.

Roy in Silver · Jan 4, 2017

jimjm said:
Mine has always done the same thing. It lasted over 5 years with the same battery, and I only replaced it because I wasn't sure how old it REALLY was. Might have been 10 years old.

If I'm not going to use the meter for a few months or more, I take the battery out just in case it starts corroding when I'm not looking.

That is very reassuring, jimjm! Thanks very much for taking the time to reply.
Roy

Roy in Silver · Jan 5, 2017

Roy in Silver said:
Hello all and Happy New Year!
I have just acquired a Gossen Luna Pro F meter. The battery in it was dead so I got a new one, a Duracell MN 1604, 9V.
The meter is working and giving what appear to be accurate exposure measurements. However, when i perform the Battery Check the meter's needle kicks too high, being far outside the green band that is supposed to indicate the correct voltage range. The green band is labelled BATT, just to the right of the 0 centreline, in the image shown here.
View attachment 170271

Should I be worried about this? Is this something that anyone else here has encountered?
Thanks for any advice!
Roy

Thanks to all responders!
For your information:I found this APUG thread from several years ago.
(there was a url link here which no longer exists)
It confirms, as some of you have already suggested, that my meter is behaving normally. Hurrah!

AgX · Jan 6, 2017

The problem is, that two manuals say the needle must be within that area, a third one however says it to be within that area or to the right of it.
We cannot exclude that calibration issues are involved too.

Another mess at Gossen...

Roy in Silver · Jan 6, 2017

AgX said:
The problem is, that two manuals say the needle must be within that area, a third one however says it to be within that area or to the right of it.
We cannot exclude that calibration issues are involved too.

Another mess at Gossen...

I agree, AgX.

However, in addressing my own original posting, I assume that the manufacturer, Gossen, being German, used precisely the correct logical description in the (original) German language manual. According to the dialogue in the earlier thread, the German manual uses the phrase "oder rechts davon steht", with reference to the green BATT. box. That means, it seems, "or stays to the right of it".
This fact, together with the statements of other Luna Pro F owners, has greatly reassured me.

Perhaps we should write our concerns to Gossen.

AgX · Jan 6, 2017

They do not even service them any longer...

Helios 1984 · Jan 6, 2017

Roy in Silver said:
I agree, AgX.

However, in addressing my own original posting, I assume that the manufacturer, Gossen, being German, used precisely the correct logical description in the (original) German language manual. According to the dialogue in the earlier thread, the German manual uses the phrase "oder rechts davon steht", with reference to the green BATT. box. That means, it seems, "or stays to the right of it".
This fact, together with the statements of other Luna Pro F owners, has greatly reassured me.

Perhaps we should write our concerns to Gossen.

Good detective work.

My Luna Pro F do the same.

frank · Jan 6, 2017

Lost in translation.

AgX · Jan 6, 2017

No not at all, there are two german manuals contradicting each other.

Also if the needle is to swing out far to the right the design of that green field in inappropriate.
Bujt to be fair. many state of battery indicators at photographic gear is ambiguos and one needs to look up things in a manual.

And such is not only limited to state of battery indicators.

Gossen Luna Pro F meter: Battery check

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