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Aaron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 10, 2004 - 08:50 pm: | 
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The light meter of my OM-2N shows some disparity between MANUAL and AUTO. The MANUAL reading is 1 stop slower than the AUTO one (e,g. with the same aperture value the MANUAL reading is 1/125s while the AUTO reading is 1/250s). How can I fix it? Thanks! |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 13, 2004 - 11:49 am: |
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Well, this ought to be fun: First a caveat: the following is from the factory service manual of the OM2; I do not have the manual for the OM2N and I do not know how similar they are in these details.
According to the manual for the OM2, the matching of the AUTO and MANUAL meter readings is a function of Resistor R305, which is located on circuit board CE0591. From what I can see, this looks like the main power switch board under the AUTO/OFF/MANUAL selector lever... which would make sense I suppose. Even within the OM2 series, this board evolved a bit, but R305 looks like it runs from the left-rear-most position on the board, diagonally forward to a point toward the forward/left relative to the other resistors on the board. Its specified value in the OM2 is 6300 ohms (the color code for this would be BLUE-ORANGE-RED). If you can identify this resistor and replace it with a variable resistor running to, say, 10,000 ohms, you might then be able to adjust to obtain a match between the two. Hopefully the result would be the correct reading, as opposed to the one-stop-off one.
This is why I do not like to work on electronic cameras.
 = |
Aaron
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 14, 2004 - 06:54 pm: |
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Many thanks Rick, I'll give it a try. Aaron |
rick oleson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 14, 2004 - 09:42 pm: |
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buenos luckos
= |
Bill Pearce
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 17, 2004 - 11:34 am: |
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This is normal, if my memory serves correctly. the manual reading is from cells at the eyepiece, like the OM1, and the Auto readings are from the OTF cell. There are, in effect two different meters. If you do try to make the two agree, remember to account for light coming in the eyepiece. |
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