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09-09-2018, 09:20 PM   #1
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MX not firing radio trigger

I have an MX that fires reliably with a flash mounted on the hot shoe (Sunpak 433D). I have cheap, no-name, radio triggers that fire from just about any other camera I have, except the MX. Doesn't matter if the radio trigger is mounted on the hot shoe or connected with an X-sync cable. Any idea what might be going on? Could the MX not provide enough voltage to the radio trigger? I have fresh 357 batteries in the MX. For what it's worth, the MX was CLA'ed a little over a year ago.

09-09-2018, 10:22 PM   #2
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Try it at well below the max sync speed, in manual at something like 1/60th sec and see if that works
09-10-2018, 02:00 AM   #3
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The camera doesn't provide a voltage to the hot shoe or PC socket; it's just a switch. There's lots of results if you Google MX and flash, and from a brief look (I knew what I was looking for) it seems that the switch contacts can oxidise.

Your flashgun has a trigger voltage of about 6.4 - 14 volts, see here (this goes through the switch in the camera) and it might be that the radio triggers have a much lower trigger voltage which can't punch through the oxidisation. When the MX was built, this wasn't a problem. Your Sunpak's trigger voltage is a low one for back then. I presume you've been using the camera regularly so exercising it wouldn't make much difference; the switch will operate every time you press the release.

It might be possible to get it cleaned, in which case tell them what the problem is, don't just ask for the contacts to be cleaned as it may be a poor connection elsewhere. Good luck, sorry I can't be more help.
09-10-2018, 07:24 AM - 1 Like   #4
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QuoteOriginally posted by Robot camera Quote
The camera doesn't provide a voltage to the hot shoe or PC socket; it's just a switch. There's lots of results if you Google MX and flash, and from a brief look (I knew what I was looking for) it seems that the switch contacts can oxidise.

Your flashgun has a trigger voltage of about 6.4 - 14 volts, see here (this goes through the switch in the camera) and it might be that the radio triggers have a much lower trigger voltage which can't punch through the oxidisation. When the MX was built, this wasn't a problem. Your Sunpak's trigger voltage is a low one for back then. I presume you've been using the camera regularly so exercising it wouldn't make much difference; the switch will operate every time you press the release.

It might be possible to get it cleaned, in which case tell them what the problem is, don't just ask for the contacts to be cleaned as it may be a poor connection elsewhere. Good luck, sorry I can't be more help.
Ah, this makes sense. Thanks for the pointer. I have to go into the shop to pick up another camera they're working on soon. Will bring the MX in and explain the problem.

09-11-2018, 09:17 AM - 1 Like   #5
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QuoteOriginally posted by murrelet Quote
Ah, this makes sense. Thanks for the pointer. I have to go into the shop to pick up another camera they're working on soon. Will bring the MX in and explain the problem.
To follow-up, I was playing around and managed to get the MX to fire the radio trigger about 50% of the time.
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