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June 2013: Spotmatic F

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Voir texteI received this Spotmatic F, in superb condition, but the exposure meter does not work: Needle is stuck up regardless of the amount of light and the selected aperture
I suspect a defect in CdS sensor as for the recently revised SP 1000.

Voir texteMy brother Christophe bought late 2010 a Spotmatic F wreck. The pentaprism-sensors block is already removed, I can borrow the CdS sensor block.

Voir texteThe top cover removed, remains to exchange sensors.

Voir texteOn the Spotmatic, Spotmatic II, SP 500 and SP 1000, two CdS cells are attached to the right and left of the sighting window. On the Spotmatic F, there are three cells mounted on a complete circuit, with adjustable resistances for calibration.
Surprise, there are two models of circuits, the wiring is different. After verification, you simply have to follow the color of the wires.
Bad news, after the exchange, the fault is still present. I'll try a third sensor block (from a K 1000), then try these sensors on another Spotmatic F (fully functional, but waiting since three years for me to find a top cover!). Conclusion: I have three fully functional circuits, the failure is somewhere else.

Voir texteThe electrical circuit has no "active" component which could burn. Remains the galvanometer. I try the one from a wreck of K 1000, for more than ten years in parts in my stock. And it works!

Voir texteI have cleared all around for the exchange of galvanometers without risking to bend the needle.
I reinstalled the original sensor cells, and tested the functionning before reassembly.

Voir texteAnd here is, with a 1.4/50mm, a beautiful fully functional Spotmatic F!

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