M5 light meter

[giacpog]

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I recently bought a used M5 (three lug version). I am about to test the light meter, because the reading does not coincide with my standard light meters (typically one stop off, overexposing, mainly at low light levels). Before proceeding, i.e. either play with the resistors or check the mechanical couplings, I need an information. Can somebody tell me where the reference line connected to the speed dial should point, when the speed setting is set at 1/1000 s and ASA setting is at 100? In the T.Tomosy's book "Leica Camera repair handbook", one reads (page 35) that with these settings "the reference line should coincide with the battery check mark..." . My M5 behaves differently: the reference line coincides with the battery check mark (actually a notch) when the ASA setting is 200 and speed at 1/1000. Either my M5 is mechanically out of order or the sentence in the book is wrong. Can some of the happy owners of a fully working M5 check this point and post his answer? Thanks a lot.

Giacpog

[john_newell]

Are you using a 1.5v alkaline or silver cell in a camera that is calibrated for a 1.35v mercury cell (as it was shipped from the factory)?

[jc_braconi]

Make a 12 exposure film and let us know what are the results.

[giacpog]

Thank you for the answers. I am using a zinc-air cell which delivers the proper 1.35 V (nominally). However, my point is different and only refers to the mechanics. In order to be clear: with reference to what you see in the lower part of the M5 finder, I am calling "reference line" the thin line whose position depends only on the speed and ASA settings; on the contrary I am calling "needle" to the other thin line which moves according to the light intensity and stop position. Now, I am simply asking (for the moment) if somebody, who has a working M5, can do the following favor: set the ASA at 100, set the shutter at 1/1000s. Then take a look in the finder and tell me if the "reference line" is in the middle of the battery check mark, i.e. the notch where the "needle" should go when checking a proper (1.35V) battery. In other words I firstly want to be sure that the previous owners of my M5 did not bump the internal mechanics. Depending on your answers, I'll proceed with the next step: either fix the internal mechanics couplings and/or recalibrate the electrical part.

Thanks again

Giacpog

[gero64]

I own two M5s.In both the reference line coincides with the notch of battery check at settings 100 ASA and 1/500.

regards gero64

[giacpog]

Dear Gero64,

thanks a lot. This is exactly the answer that I expected. Even in my case I have the same situation. Matching of the reference with the notch is obtained for 1/1000s and 200 ASA. In other words T.Tomosy's book (on this item) is wrong, and the mechanics of my M5 is correct. Therefore, overexposure is probably due to some mis-adjustment of the CdS cell and/or battery circuitry. I will try to operate on the two variable resistors in the electrical part of the meter.

Really, thanks a lot

Giacpog