Gossen Luna Pro F

[Chuck_P]

My Gossen Luna Pro F that I use for general photography will not respond to the battery test button with a fresh battery.......is it fried or does anyone think it can be fixed. There's good battery connection and the wires look in good shape. Thanks.

 

[Sirius Glass]

Clean the battery contacts. That may help.

 

[Helios 1984]

Does it meter?

 

[Kyle M.]

You probably already know this but just in case you don't you do have to hit the button to take a meter reading to turn the Luna Pro F on then you can hit the battery test button. The meter times out and turns off after something like 30 seconds.

 

[Chuck_P]

Sorry should've stated that it doesn't respond to the meter button either

 

[eli griggs]

Could also be the switch wires have corrosion and broken.

Let us know what you find out.

 

[Marcelo Paniagua]

I used one of this sometime ago. For mine, wires that connect to the batteries where damaged. My test was to take the battery out of the light meter and carefully move it around a bit. If the wire has a shorts circuit it Will power on/off the meter when you move the battery.

Mine had this problem and, since I had others lightmeters, gave it away. If this is your case, it should be an easy fix if you are good with electronics.

 

[awty]

Mine just had a wire which come unstuck easy fix.
Heres a thread I prepared earlier

Gossen profisix light meter repair.

I bought a bag of camera stuff and this meter along with other stuff wasn't working. Just want to write a note to myself and maybe others who want to pull one apart and can't find any info on doing so. You need to desolder the three metal tabs going to the potentiometer as well as the 4 screws...

www.photrio.com

 

[MattKing]

The 9 volt battery connectors can wear and require replacement.

 

[Chuck_P]

The battery connectors are nice and tight...interesting, I took the battery out and put it back in, then the battery test worked for about three pushes on the test button then stopped (Still never metered)......took battery out and put it back again, battery test worked for another three pushes on the test button......I repeated that a few times.......still never metered though. The connectors are clean snug.

 

[MattKing]

The wires within the connector and harness tend to wear out.

 

[Chuck_P]

I think its toast

 

[awty]

I think its toast

Probably not toast, just needs fixing. The circuitry is pretty simple. Take it apart and take a look. I've fixed two that weren't working and I'm not very smart.

 

[eli griggs]

In testing your meter wiring and contacts, try using 1/4" - 1/2" duel conducting sided copper, self-adhesive tape.

It's cheap as dirt and will allow you to bridge bad connections.

Some people simply leave the tape on the wire/connection but I suggest if you can no protect the current with electronic shrink tube, you mix or buy some three pound (3#) Shellac and carefully paint your wire/connection carefully with it, allowing it to dry well between two or three coatings.

I first learned about this minimalist method in an video on doing the same on a Weston Master IV connection wires from it's solar cell, with shot wires and solder.

Give it a try, and remember, lots of battery and cell items will need such repairs, in your future.

IMO.

 

[Chuck_P]

Probably not toast, just needs fixing. The circuitry is pretty simple. Take it apart and take a look. I've fixed two that weren't working and I'm not very smart.

I attempted to take it apart, had the back aluminum plate off that exposed the green circuitry board, then there were 4 small but long brass screws in each corner of the board that I took out, but the circuit board still won't budge, so I don't know what's holding it in place............i would only be able to detect something that is blatantly obviously not connected or damaged. So if anyone can tell me how to free up the circuit board, I'll give it another shot.

 

[eli griggs]

Do you have a multimeter to hand with which you may test circuits?

If no, drop by a Harbor Freight and pick up their inexpensive red meter, which they use to offer free with purchase, but may cost almost $10US, so you have a connection feature, volts and micro amps to check out current and connections

DO NO FORCE ANYTHING?

Does anyone know if Loctite is used on this meter?

I've only taken apart Gossen Luna Pro SBC, meters in the past, never needed to do this with my Luna Pro F (U.S.) as you know, these things are tanks in their own right and battery leaks and corrosion one of the few things that can put them out of action (IMO).

Take your time, do it right or have someone whom knows the meter repair S.O.P.s do it.

Lastly, do you carry this meter in it's case, which offers very good protection.

Let us know your final resolution of this repair, please.

 

[awty]

I attempted to take it apart, had the back aluminum plate off that exposed the green circuitry board, then there were 4 small but long brass screws in each corner of the board that I took out, but the circuit board still won't budge, so I don't know what's holding it in place............i would only be able to detect something that is blatantly obviously not connected or damaged. So if anyone can tell me how to free up the circuit board, I'll give it another shot.

Read the link in post 8, shows how to take apart.

 

[Chuck_P]

Read the link in post 8, shows how to take apart.

I don't have soldering tools to complete that task.......I think it's beyond my abilities.

 

[awty]

I don't have soldering tools to complete that task.......I think it's beyond my abilities.

Well dont throw it out, pass it on to some with a soldering iron. Soldered joints can come lose over time and switches need cleaning.

 

[eli griggs]

Call around to your local high school and college engineering and shop teachers, asking if they or their better students could do the soldering for you, for a small fee or donation of a used tool.

Years ago, when I bought my first quality Japanese woodblock carving knives, I wanted larger handles than what came, which are made for Japanese folks with smaller hands.

I called my old high school, asked for the shop director and asked him about having some student turn handles out of exotic wood I had to hand.

He said he'd do it for a tool and as I had an old but working circular saw I could spare, that's what I took him.

He turned me three new handles, in blackest Gibbon Ebony, Chechen, and Pink Ivory (for instantly picking up the correct profile while carving) and I was set to go.

I also gave him a section of that nice Ebony for his personal use.

I suggest you look over your old electronics and see what you might trade for soldering, in case, a small cash payment is no sufficient or wanted.

A new roll of good electrical solder might do the trick as well.

Cheers,
Eli

 

[Sirius Glass]

I don't have soldering tools to complete that task.......I think it's beyond my abilities.

Call KEH and ask if they are able to repair the light meter.

 

[awty]

Call around to your local high school and college engineering and shop teachers, asking if they or their better students could do the soldering for you, for a small fee or donation of a used tool.

Years ago, when I bought my first quality Japanese woodblock carving knives, I wanted larger handles than what came, which are made for Japanese folks with smaller hands.

I called my old high school, asked for the shop director and asked him about having some student turn handles out of exotic wood I had to hand.

He said he'd do it for a tool and as I had an old but working circular saw I could spare, that's what I took him.

He turned me three new handles, in blackest Gibbon Ebony, Chechen, and Pink Ivory (for instantly picking up the correct profile while carving) and I was set to go.

I also gave him a section of that nice Ebony for his personal use.

I suggest you look over your old electronics and see what you might trade for soldering, in case, a small cash payment is no sufficient or wanted.

A new roll of good electrical solder might do the trick as well.

Cheers,
Eli

Great suggestion, there is also plenty of old retired electronics people who could easily fix.......just mention that they need to desolder the three legs on the main potentiometer , the rest is straight forward.

 

[VinceInMT]

I don't have soldering tools to complete that task.......I think it's beyond my abilities.

It’s not beyond your ability to learn. Soldering and desoldering is a fairly simple skill and there are lots of YouTube videos to help you out. Pick up a low wattage iron, some solder (thin type), and a solder sucker. Practice on a couple wire twisted together that are clamped or taped down to something. You will probably encounter other things in life that will benefit from having this skills.

Full disclosure: I’m a retired high school shop teacher and taught lots of kids how to solder. I’m the owner of a Luna Six 3 (Euro version of the Luna Pro.)

 

[eli griggs]

Harbor Freight has a simple iron for no much money and other related things so stop in and look at what they offer.

The hardest things about soldering, IMO, is getting the wiring and iron tip CLEAN and learning to apply and judge when they are getting enough heat.

Learn that and you've learned to solder, only needing to get you're technic and work flow fine tuned for really strong connections.

Make sure you get the correct flux and solderand "tin" your iron tip before anything else.

VinceinMT can correct my errors, as newer materials and technology exist.

 

[VinceInMT]

Harbor Freight has a simple iron for no much money and other related things so stop in and look at what they offer.

The hardest things about soldering, IMO, is getting the wiring and iron tip CLEAN and learning to apply and judge when they are getting enough heat.

Learn that and you've learned to solder, only needing to get you're technic and work flow fine tuned for really strong connections.

Make sure you get the correct flux and solderand "tin" your iron tip before anything else.

VinceinMT can correct my errors, as newer materials and technology exist.

I agree. Get some tools and give it a try. A couple things I’d add are that when soldering a connection, attempt to make a good mechanical connection first, such as twisting wires together, making a secure loop though an eyelet, etc. and then applying the solder. Also, keep in mind that the solder will run toward the heat so the iron goes on one side of the connection and the solder is applied to the other side and it will then run into that mechanical connection.

Yes, obtaining the correct solder is important. Don’t use the type used in plumbing. I use a 60/40 rosin-core solder that is .032” diameter for general electronics work. My iron is 25 watt. Occasionally I use a solder paste flux to clean the connection. Since removal of old solder is sometimes required, I use a solder sucker, essentially a spring-loaded vacuum. The only other tool I find invaluable is a “third hand” which is a heavy metal base that has an adjustable armature with alligator clips on the ends. It can hold the parts while the dolding takes place.

Like mentioned, this stuff is available at Harbor Freight. If one really gets into it, a “soldering station” with adjustable power, solder vacuuming system, lighting, and such can be obtained. It’s pricey.