My original post contained:
<< I don't have the official OM1N schematic but assuming it is
>similar to the the OM2N in so far as the flash is concerned then the OM1N
has
>two sets of sync switches one for FP and one for X.
>>
john@xxxxxxxxxxxxxxxx commented:
<<
I have a copy of an OM1 manual and, according to that, there is no
diode isolation circuit (unlike the OM2).
>>
I also have the official OM1 manual and you are correct the OM1 is not
polarized.
My post specifically (and the topic title) refered to the **OM1N** which is
polarized with a diode.
My comments about diagnosing the **OM1N** problem refered to the OM1N not
the OM1 you are now discussing.
Your second comment about the OM2 circuit is true for the OM2N*** but NOT the
OM2.
The official OM2N service manual contrasts the flash sync circuit changes
that took place going from the OM2 to the OM2N.
This shows the OM2 has no isolation diode while the OM2N does have an
isolation diode.
To check my original post about how to test the diode in the OM1N,
I tested for the diode in my OM1N: by setting the switch to FP and testing
for the presence of a diode between the hotshoe terminal and ground using a
digital multimeter.
Result the diode was detected as expected.
With the switch in the X position the diode could no longer be detected (as
expected) since
the switch opens the ground circuit to the diode. (Just as in the OM2N.)
I checked some notes I made a while back on the OM1N ( while modifying the
meter for
silver oxide batteries) and the flash circuit diode *is* mounted on the pc
board under the
top cover near the front left corner of the camera (when viewed from the back
of the camera).
As a general comment the diode used should be a very reliable in this
application and the chances of it failing are low.
Regards,
Tim Hughes
>>Hi100@xxxxxxx<<
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