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Waynemel
Tinkerer
Username: Waynemel
Post Number: 173
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 08:33 am: | 
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Has anyone disassembled the selection disk/scale on one of these meters?
On my copy, the clear disk on top tends to slip away from the metal inner scale when selecting the ISO setting. It appears that the clear plastic part is worn where it should have a shoulder to engage with the metal scale, so both would rotate at the same time. I would like to take the clear disk off and perhaps clean-up the shoulder or bend the metal disk to improve the engagement.
I am able to remove the top of the meter, and it appears that the disk assembly is riveted, but I'm not sure. Has anyone tried to do this in the past? |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 274
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 08:53 am: |
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yup. AFAIR the center disc (sun/moon) is a screw and can be friction-unscrewed. Only if my memory serves me right...
Marek |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 174
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 20, 2012 - 07:02 pm: |
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Do I have to pry up the sun/moon logo to reveal the screw, or will the entire thing unscrew? |
Glenn
Tinkerer
Username: Glenn
Post Number: 999
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 07:47 am: |
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Check the archives for information!!
Yes - but center screw can be bloody tight, so removed alloy center disc with a needle and then carefully drill two holes in screw head to take a pin wrench.
The iso/setting assembly is held tight by a 'wave' washer, this may be bent to give more friction but new parts are the way to go.
Note Gossen will provide gratis consumables and small parts - the alloy center disc and the alloy back data plate being just two of these. Go to the following -
http://www.gossen-photo.de/english/fotografie.php
Click on the repair 'box' and read ALL the information. If yours is a meter that can be repair by Gossen, fill in the request form with the description of the bits you require. Note that They have supplied me with new clear front discs for the black cased 3s at no charge in the past. However I now note that there is a postage/handling charge of 6 euro or 13 euro depending on size of parts required |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 175
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, May 21, 2012 - 08:32 am: |
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I did check the archives and didn't find anything. (I have been here for a while).
Thanks for the info.
I don't think the parts are available from Gossen ans my meter is the older grey version. |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 287
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 23, 2012 - 02:39 pm: |
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Take the center screw out by using a rubber glove or anything to give more friction n unscrew it.. no need to take the moon plate off.. there is no disk to take off.
The screws to take her appart are under the back tin plate.
After taking all the screws out, you will be able to split the case.
. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 177
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, May 23, 2012 - 03:31 pm: |
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Already fixed. I took off the logo plate. Underneath there are two holes for a pin wrench. I tried to use friction before removing the logo, but it was too tight. |
Glenn
Tinkerer
Username: Glenn
Post Number: 1001
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 24, 2012 - 06:02 am: |
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That is intriguing - except for the ones I modified, this is the first time I have come across these screws with wrench holes on a meter owned by a third party. Obviously somebody has had the same problem as I did on a number of occasions, because i do not think this was a factory modification - certainly not on the grey cased Lunasix |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 288
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 24, 2012 - 07:21 am: |
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ummm I'm looking at my Luna Pro now n see no plate over it, the moon thing IS the head of the screw.
. |
Glenn
Tinkerer
Username: Glenn
Post Number: 1002
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 24, 2012 - 11:02 am: |
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No, you will find that the moon/sun disc is infact an anodised alloy disc that is glued into a recess in the center screw head. If you place a very fine needle (I use a fine hypodermic needle) between the plated upstanding edge of the screwhead and the outer edge of the disc, you will find that you can gently lift the disc out. One should note that the dab of contact adhesive holding the disc is almost never placed in the disc center -this means that if the disc is difficult to raise when you first place the needle in the narrow gap, move needle to opposite side of disc and try again. Almost always you will be able to raise the edge of the disc enough so that you can place a thin knife blade between disc and screwhead, allowing the disc to be carefully pried free.
As I have said before, Gossen will provide new discs and alloy rear data plates (ie the bits that may get bent when a meter is serviced) for a nominal handling charge for black cased models. From memory the same alloy 'moon' disc was/is used on both grey and black cased instruments. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 179
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 24, 2012 - 12:37 pm: |
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When I removed the logo plate (as Glenn described), it certainly looked all original. I was expecting to drill my own holes as mentioned. One hole was dead centre, the other was about 4mm away . It certainly looked to be fresh from the factory. |
Glenn
Tinkerer
Username: Glenn
Post Number: 1003
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 25, 2012 - 10:24 am: |
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Even more interesting as the placement of the holes is certainly unusual - standard accepted engineering norm is to place them diametrically opposite, as near to the outer edge as possible. Unfortunately I have never stripped a grey cased Lunasix completely down as I only consider the black cased 3s versions worth repairing, but having refurbished around a dozen over the years I have never seen pin holes in the 3s center screwhead.
Now there is a logical reason why center screws with pinholes are found on the early (grey) models and the later improved black models had solid headed center screws - Cost Cutting. The Lunasix was always an expensive meter and the vastly improved circuitry in the black 3 and 3s models certainly pushed the price up. Did Gossen do a cost analysis and shave a few pennies off the price by simplifying the manufacture of certain metal components to keep prices competitive? This was certainly done by Canon during the manufacturing life of the A1 - in the first series most of the gearing is metal and you can strip the camera down to the chassis without needing to unsolder wires. Cameras that came after this first batch started to contain more and more plastic parts and connectors that allowed one to just lift off the top plate were replaced by wire and soldered joints. The exercise worked for Canon as the A1 remained price competitive throughout its life: however, in the longevity stakes the later models cannot hold a candle to cameras from the first batch. |
Waynemel
Tinkerer
Username: Waynemel
Post Number: 180
Registered: 08-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, May 25, 2012 - 03:37 pm: |
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I was unaware that the later black versions of the LunaSix were so different. What affect did the changes have on the functioning of the meter? |
Agchicago
Tinkerer
Username: Agchicago
Post Number: 1
Registered: 06-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 12, 2012 - 10:43 am: |
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Like Glenn, I've refurbished a dozen or so Luna's, but only the LunaPro and original LunaSix (euro version of the LunaPro). On all of those, there are no spanner holes, it's a solid disc. Drilling the holes makes the job easier the next time for sure.
Interestingly, the later black LunaPro was considerably cheaper in build quality then the old grey standard (especially the meter movement). But...even with the grey versions, small design changes were made over time.
I'll post a pic tonight of the innards, I have a few "in process" for refurb. |
Stanblute
Tinkerer
Username: Stanblute
Post Number: 3
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 06, 2012 - 07:27 pm: |
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On the older gray Lunapro's the screw shaft on the calculator pivot is hollow. The easy way is to just pull the whole front cover off and then push a small wire through the screw from behind. The sun/moon plate pops out and you can get the pin wrench on the two holes under the plate. I have some replacement parts for the dial assembly if you need them. I mainly work on the gray ones and the main difference I've found between them and the newer black ones is that the photo cell on the black ones is much better adapted to the color response on my newer SBC meters. When you meter green or brown with the gray meters they vary up to a stop compared to an SBC meter. But the black meters mirror the response from an SBC cell regardless of what color the reflecting surface is. Have you done the diode adaptation to use silver cells? A miniature diode from Radio Shack, two solder joints, and you have a modern adapted meter, usually with only minor calibration needed. I can send you directions to calibrate it if you need them. All you need is an accurate meter or camera meter to use as a reference.
Skip |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 304
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 07, 2012 - 07:44 am: |
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What is the Radio Shack part number of the diode you use in your battery update?
Perhaps poting the calibration here will save some people alot of trouble in the future?.. prividing they use the search feature. |
Stanblute
Tinkerer
Username: Stanblute
Post Number: 4
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 07, 2012 - 12:42 pm: |
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turns out, all you need are these two links.
http://www.flickr.com/photos/polapix/2609042974/
http://www.biasedlogic.com/index.php/calibrating-gossen-lunasix-3-lunapro/#more- 171 |
Paul_ron
Tinkerer
Username: Paul_ron
Post Number: 305
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 07, 2012 - 04:53 pm: |
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That second article was great. Thanks. I'm sure that will clear up alot for many people.
I personally have leared to compensate my meter for the difference in using newer batteries by calibrating my exposures to my developing technique to my printing so my results are consistant and predictable each time I take readings with my meter.
For all I care I can use a VOM with a CDS cell to measure the light as long as I know exactly what the outcome is going to be in my print.
So "accurate" and "precise" are relative, not an absolute as you will find from meter to meter; your results will vary.
. |
Stanblute
Tinkerer
Username: Stanblute
Post Number: 5
Registered: 09-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 07, 2012 - 05:48 pm: |
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My darkroom days are over - no room in a tiny apartment. So I spend more time on the hardware and rely on the local lab to give me consistent processing. I try to shoot print film as if it's slide film so I can do a standard scan on the negatives and almost never have to do any tuning on the individual frames. That's why I've gotten pretty obsessive about having all my meters and cameras read as identically as I can. That, and it's fun to be obsessive sometimes. Ha! Do you still want the part number for the diodes? I tried to send it twice but the site wouldn't let me. Maybe it won't allow consecutive posts without another comment in between. And now I'm at my mom's house and don't have the number in front of me.
Skip |
Mareklew
Tinkerer
Username: Mareklew
Post Number: 279
Registered: 03-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 03, 2012 - 06:40 am: |
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@Paul:
glad you liked that article ;-)
Marek (author) |
