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Glibdud
Tinkerer
Username: Glibdud
Post Number: 1
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 14, 2006 - 09:25 pm: | 
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Hi folks. I've got an Oly OM-1n and a T32 flash that are not happy together. I've determined that the flash unit is operating properly (by shorting the center pin to ground). I've also run a continuity test on the pins of the Shoe 4 to rule that out. I've also discussed it in another forum and ruled out operator error. It just doesn't work, and it's definitely something in the camera body.
I'm new to camera repair, but mechanically competent. Could anyone explain or point me to an explanation of the flash system in the OM-1n? What am I likely to be looking for, and where are the components physically located?
I imagine it would probably help troubleshooting if I could try the PC connector, but unfortunately I don't have access to a socket that will fit that. Is there a way to rig something up to test that?
Thanks for reading... |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 60
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, September 14, 2006 - 09:51 pm: |
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If you could borrow another flash to try on the body that might help.
The only contacts that matter are the big one in the center and the metal rails on the sides. One of the 2 small pins is dead in the OM1N, and the other just lights the ready light in the finder. The side rails should have continuity to the camera chassis, and the center pin should short to it while the shutter is open. You can test that with an ohmmeter.
If you get a connection from the center pin to the side rail while the shutter is open on B, then probably the most likely problem is a failure to get contact from the side rails to the contacts in the flash foot. These are leaf springs in the sides of the recess between the foot and the locking nut of the flash... sometimes they get weak with use and don't make good contact, and then a bit of tarnish can cause a failure.
You can test the PC socket with an ohmmeter the same way, you should get a connection from the center hole to the outer shell when the shutter is open. |
Glibdud
Tinkerer
Username: Glibdud
Post Number: 2
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, September 15, 2006 - 07:05 am: |
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Good info, thanks! However, I forgot to mention something...
The flash ready light in the viewfinder works, so the rail is making good connection.
So... where are the bits that make the connection inside the camera? |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 62
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, September 16, 2006 - 04:53 pm: |
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The connection to the shoe is a wire that goes to the threaded connector on top of the prism... easily accessible when the top cover is off. If you're lucky, maybe the wire is just off. If that's not it, things become more difficult: the switches are in the bottom of the camera, and of course there are wires running from there up the middle to get to the connectors. A break in the inner area will be tough to reach.
If you would like to email me for them, I have a sketch for removing the top cover and a schematic of the synch circuit.
rick_oleson@yahoo.com |
Glibdud
Tinkerer
Username: Glibdud
Post Number: 3
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 19, 2006 - 06:33 am: |
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Thanks a bunch, Rick. I'll take a peek when I get a good opportunity to sit down and tinker, and report back (hopefully with a resolution!) |
Glibdud
Tinkerer
Username: Glibdud
Post Number: 4
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, September 11, 2007 - 01:54 pm: |
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Dredging up this old topic again, since I have some new info.
I never got around to disassembling my OM1n, and I'm in another class, so again it's not a good time. However I did pick up a parts OM1 that I can play around with.
I also acquired a hotshoe-to-PC-socket adapter so I could test the flash units in the PC socket. The results: no flash with the switch on X; flash fired with the switch on FP.
So the conclusion I'm drawing based in the schematics Rick provided me is that the problem is with the X sync contact.
I found a technical article on the camera that provides an awful lot of information, including the location of that contact (near the bottom of the camera), but I'm having a hard time figuring out exactly what I would have to do to access it. Does anyone have an intimate enough knowledge of these cameras to tell me exactly what I would have to remove to get at that? (And how dangerous is such a procedure?) |
