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T_threes
Tinkerer
Username: T_threes
Post Number: 1
Registered: 10-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 25, 2006 - 05:15 pm: | 
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Brand new to the forum. This has probably been descussed to death. If so, I'm sorry. Can I adjust my T3 meter myself to compensate for the 1.5 volt batteries that are much more plentiful than the short lived and hard to find Weincell MRB675's.
Thanks in advance |
Loosecanon
Tinkerer
Username: Loosecanon
Post Number: 11
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 26, 2006 - 09:00 pm: |
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http://www.vintagebatteries.com/battery.html |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 7
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 27, 2006 - 08:37 pm: |
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Yes, it is a relatively easy adjustment, once you have the top off the T3, involving two potentiometers and possibly a meter cable set screw. You will need to use the SR44 silver cells, because their voltage is much more constant than the LR44 alkalines.
Let me know if you need details. |
M_currie
Tinkerer
Username: M_currie
Post Number: 9
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 27, 2006 - 10:03 pm: |
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Hovaness, I would also be interested in the details on this. I've never seen instructions for doing a Konica, and always was under the impression that it's not practical.
In the meantime, what I've found works well is zinc-air hearing aid batteries. They don't last very long, especially because my T3, which usually rides loose in my car, tends to turn itself on and drain them. But they're cheap. I offset the ASA 2/3 of a stop to compensate for the voltage. |
T_threes
Tinkerer
Username: T_threes
Post Number: 2
Registered: 10-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, October 29, 2006 - 11:35 am: |
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Hovaness and all, yes I would like details step by step, or images, and proceedure for the adjustment.
I assume the LR44 silver cells are 1.5 volt? Am I correct or are they 1.7 volt? Any help would be very much appreciated, I still enjoy my old T-3's but they are becoming a source of frustration regarding the exposure meter.
Thanks again. |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 9
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, October 30, 2006 - 08:09 pm: |
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I'm going to take some pictures of the T3 potentiometers and the cable adjustment location and attach them to a posting. I will have it ready in a day or two.
The SR44 silver cells are about 1.55 volts, and they stay close to that voltage until just before they die. The LR44 Alkaline cells are the same size, but their voltage drops significantly over the battery life, so they do not provide consistently accurate readings in the simple T3 meter circuit, which relies on a stable battery voltage.
You can get good deals on SR44 silver cells on eBay. |
M_currie
Tinkerer
Username: M_currie
Post Number: 11
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 01, 2006 - 12:55 pm: |
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In my experience silver oxide cells usually start off about .02 volts or so above the alkalines, more like 1.58 compared to 1.56, though much depends on load, and recently I've seen cheap alkalines that started at a full 1.6. But since alikalines drop and silver oxides don't, the difference is likely to grow as they age. It's not a big deal for some cameras, and one can always just replace alkalines more frequently since they're cheaper, but for the Konica, which is pretty sensitive to fractional voltage, I would definitely spring for the silver-oxides if going to the trouble of calibrating it at all. |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 10
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 02, 2006 - 02:28 pm: |
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See the attached WinWord document for the location of the potentiometers for meter calibration. You will probably have to make a few iterations to get the potentiometers right, since the meter test setting affects the high brightness reading and vice-versa. You should also put black tape over the CDS cells, to block stray light, when making the adjustments. |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 11
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 02, 2006 - 02:32 pm: |
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See the attached Winword document for a drawing of the cable adjustment for low-level meter reading calibration. This adjustment point is at the back of the top of the camera near the rewind knob. |
M_currie
Tinkerer
Username: M_currie
Post Number: 14
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 03, 2006 - 08:42 am: |
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Thanks for the info. By the way, the link for the zip file results in a file with the extension "unk" but it can simply be renamed to "zip" and will unzip and open without problems.
My only question regarding the procedure, in my case, is whether it is worthwhile. I carry my "beater" T3 around in the car without a case, and because its switch is a bit worn, it tends routinely to get switched on by vibration. This kills the hearing-aid batteries quite quickly, and although silver oxide cells would undoubtedly last much longer, I still wonder if I'm better off just buying multi-packs of zinc air cells and carrying spares in the car. |
Hovaness
Tinkerer
Username: Hovaness
Post Number: 12
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 03, 2006 - 08:59 am: |
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I think you have answered your own question. You should open up the T3 just to fix the faulty switch. The T3 is a big, tough camera, with rugged parts. Chances are you can correct the mechanical problem with the switch. |
T3 potentiometers for meter calibration
T3 meter calibration notes