Gossen Lunasix 3 (Luna Pro?)

[Bassism]

Hey everybody,
I'm wondering if anybody has any experience with repairing a Lunasix 3. I just picked one up off of ebay, and it was DOA. I put a new set of batteries in and it still wouldn't work.

If I bang it around a little bit while holding the battery check button, I can get a response from the needle ranging anywhere from a half to a full charge. This leads me to assume that the batteries are making faulty contact.

My question is whether anybody has any experience with these meters. Either tips about likely points of failure, or even just tips on disassembly.

Thanks for any help

 

[Larry Manuel]

I have a good one and a spare one. Somehow the glass broke on my good one and I disassembled it, and replaced the glass. It still works.

To disassemble, heat the thin aluminum plate on the back, which will soften the glue. While it's warm, gently pry it off, then remover the screws. The case will then split in half, giving good access to the guts. A hot hair drier should do it.

Now I'm speculating: My spare Luna Six has the same wavering needle syndrome. My batteries are fine [work OK in the good Luna Six], thus I suspect it is suffering from oxidized contacts on the switch[es]. My plan is to pull a very fine-grit piece of silicon-carbide wet-dry sandpaper through the contacts a few times to clean them. Something like 400 or 600 grit.

The glue will likely stick well when you re-apply the plate, cold.

Good luck. I love the meter.

 

[plummerl]

Hey everybody,
I'm wondering if anybody has any experience with repairing a Lunasix 3. I just picked one up off of ebay, and it was DOA. I put a new set of batteries in and it still wouldn't work.

If I bang it around a little bit while holding the battery check button, I can get a response from the needle ranging anywhere from a half to a full charge. This leads me to assume that the batteries are making faulty contact.

My question is whether anybody has any experience with these meters. Either tips about likely points of failure, or even just tips on disassembly.

Thanks for any help

I purchased a Lunasix 3 (it is the European version of the LunaPro) and sent it to Quality Light Metric (Hollywood, California) for repair and calibration. The cost was very reasonable, the quality of work exceptional. You can call George and discuss it with him (http://losangeles.citysearch.com/profile/55388/los_angeles_ca/quality_light_metric_co.html).

As far as batteries, I am using the Gossen battery adapter, converting it to use standard silver batteries. The original uses the extinct mercury ones.

The meter is fantastic.

 

[Bassism]

Thanks guys,
I would love to be in a position to send it out to QLM, but I don't have the cashflow to do that at the moment. And even if I did, a CLA on my M2 would take priority. But I'm nothing if not prone to taking things apart and trying to put them back together again!

It would have taken me forever to figure out to take off the aluminum plate, so I'm glad I asked before I took tools to it. I also hadn't thought about the contacts on the switches, that's a good idea. I'm pretty confident I'll be able to get the thing back into serviceable condition, it's got to be something simple. I'll report back once I get the thing pulled apart.

 

[ItsReallyDarren]

What kind of batteries did you put in the meter? I use the 675 zinc air cells in mine, but because they are slightly smaller I have to use an aluminum shim to get the battery to contact properly.

 

[Bassism]

Hm, I did buy a set of weincells to use with the meter, because I use 625 hearing aid batteries in a lot of my cameras and wanted the metal rings. I didn't know that they weren't as tall, I'll try adding some tin foil when I get home.

 

[navilluspm]

I have a question.

Locally a man is selling his Lunasix 3 with the 15 anf 7.5% "spot" meter attachment for $60 CAD. I would like to get a good meter and have no idea is this is a good price or not. So what do you think? Is it a good price?

 

[Roger Vadim]

good meter, but you need that battery adaptor, or another solution for the extinct mercury cells. it really shines in very low light. don't know about the price, over here in germany they sell for about 50-70 euros without the spot thingy (which I would like to have).
I don't really trust mine 100%, its an old grey one, means its 30+ years old and although it works, and is super spot on with most of my other meters, it feels a bit old... (the ones with the black housing are much younger and still being sold, I'd go for one of them)

 

[puderse]

Bought a Lunasix 3 in 1970. About 5 years ago I decided that it was time for a CLA. Sent it to factory repair and had it converted to modern batteries (size 44?). Used it last week. Still depending on it. A good one, mine's gray, will last longer than you.

 

[Bassism]

Navillus, I think that's quite a good price for the Lunasix. With shipping, mine was nearly that much, arrived DOA, and doesn't have the spot attachments. The spot adaptors on their own seem to go for 40-50 dollars on ebay.

I just pulled mine apart and there is quite a bit of corrosion on the leads. I'll have to pull out the multimeter and figure what exactly's going on.

 

[nikon_sam]

I have a question.

Locally a man is selling his Lunasix 3 with the 15 anf 7.5% "spot" meter attachment for $60 CAD. I would like to get a good meter and have no idea is this is a good price or not. So what do you think? Is it a good price?

If you need one...buy this one...that's a good price...😀
If you can...give it a test run...

 

[Bassism]

I've got my meter to a point where it seems to be working. The battery check is still completely useless, but it gives readings that seem to be reasonably close to correct. I'll have to test it against my dslr whenever I find my batteries.

One thing I have noticed is that it will only give a reading if it is held perfectly horizontal. I don't know if this is typical, it seems to me that the galvanometer might be kind of weak. But I don't know what would affect this; I can trace the correct voltage through the whole meter, and beyond that my knowledge about galvanometers fails.

I guess I'll just have to put it through its paces and see how things go.

 

[MartinP]

I've been using one of the black ones for about twenty-six years, and even then I bought it secondhand. No complaints so far, and I'd recommend the Gossen battery adapter too as it totally solves the mercury-battery problem in the simplest and most reliable way.

The scale goes down to an EV of minus eight, which would be around eight minutes at f1,4, when using 6 asa.... I have never used it below an EV of minus one though, when it took a while to get a deflection, but it did work successfully and the measurement was repeatable (the pics worked too, with the allowance for reciprocity failure).

The only problem might be the size - in it's case, the meter feels as big as my Zorki-1, though a lot lighter.

 

[FallisPhoto]

Thanks guys,
I would love to be in a position to send it out to QLM, but I don't have the cashflow to do that at the moment. And even if I did, a CLA on my M2 would take priority. But I'm nothing if not prone to taking things apart and trying to put them back together again!

It would have taken me forever to figure out to take off the aluminum plate, so I'm glad I asked before I took tools to it. I also hadn't thought about the contacts on the switches, that's a good idea. I'm pretty confident I'll be able to get the thing back into serviceable condition, it's got to be something simple. I'll report back once I get the thing pulled apart.

Always check the simpest likely problem first -- the wires connecting to the battery holder. On ebay cameras, meters and etcetera, the most likely thing to have caused damage of that type is that someone left a battery in it for a few years and it leaked.

 

[rbickford]

Gossen Lunasix-needle trap

Gossen Lunasix-needle trap

One thing to check if the needle is not moving freely is the needle 'trap'. When you slide the battery check mechanism or depress the meter level selector on the side, this opens a jaw that is holding the needle in place. Releasing tightens the jaw and holds the needle in place. See the drawing here:

http://rick_oleson.tripod.com/index-126.html

If you open the meter you can check if the trap is still touching the needle when the battery check or meter level selector is engaged. If so adjust by widening the trap some or if the needle is bent, straighten it. To open the meter you have to peal off the plate on the back to access screws that holds the front and back pieces of the meter together.

The drawing referenced above may not be accurate for your meter, but all the Gossen meter traps work the same way.

 

[Eugen Mezei]

Just let me remember you (oh, well...) that I still have fresh mercury cells from actual production (Silva/GP) and will gladly sell them to anyone interested at a very reasonable (I think) price.
Just drop me a PM.

Eugen

 

[Bassism]

Thanks for the link to Rick's site. Those drawings may come in useful in the future.
For now, I've got the meter to the point where it is giving accurate readings. The battery check still doesn't work, which leaves me clueless, but it fulfills its essential function as a meter.
As far as batteries, I'm good to go with my zinc hearing aid cells for a while yet.

Thanks to everybody's advice! And you're all right, in good working condition, this is a great meter.

 

[FallisPhoto]

The battery check still doesn't work, which leaves me clueless, but it fulfills its essential function as a meter.

Bad switch? The battery check button not working is a common problem with some cameras, but that is usually because they are using silver oxide cells with a shotkey diode, which has an effect on the current. You're using zinc/air batteries though, and that can't be it.

 

[navilluspm]

Sorry to hijack this thread too - but I also got that Lunasix with tele attachement. I tried some batteries from the camera store which were obviously wrong (showing readings that were 3-4 stops too fast). So here is my question: should I send it to Precision Camera in Winnipeg where, for between $45 - $75 CAD, they will covert and calibrate the meter, or should I just get a Gossen adapter from BH photo video?

Precision Camera does not use the Gossen provided adapter, but their own. Price depends on how much they have to calibrate the meter after conversion. I think I would like the have the meter calibrated, but would there coverter be as reliable as the Gossen made battery adapter?

 

[Eugen Mezei]

Price depends on how much they have to calibrate the meter after conversion.

That is weird. For almost two decades camerarepairshops made a good living for themselves selling this "recalibration" legend. But these one tops it all. After telling you they can recalibrate they also tell you the effort is dependent on the amount of conversion. :bang:

Boys, simply accept it (better: read and understand why) that such a thing as converting mercury based lightmeters can not exist.
Buy real mercuries or as a second option Zn-air batteries. Don't throw your money out the window for so called conversions.

Eugen
(happly selling fresh mercuries to anyone contacts him)