So I have a new AmazonBasics flash gun and I tried to connect it to my camera with a PC cable. As soon as the PC plug touches the internal circle of the PC socket on the flash, it fires. However, when I press the shutter button on my camera, it does not. Has anyone else had this problem and is it more likely that the cable is faulty or the Pc port on the flash gun? I tried googling this but wasn't successful..

The camera is a manual-only SLR. I connected the camera to the flash, and turned the flash on. After that, as soon as the cable moves a little bit, the flash would fire several consecutive flashes. Again, I guess it has to do with the contacts moving as the cable moves?

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    \$\begingroup\$ Can you tell us if your sync cable has the same connector on both ends? How old is the cable? It's possible that this is happening because of a polarity issue and reversing the cable (if possible) may resolve it. Otherwise it might be because of internal damage to the cable causing it to short out the connection which as a result, fires the flash on contact. \$\endgroup\$
    – KarlC
    Nov 22, 2017 at 20:54
  • \$\begingroup\$ yes. The cable is a new male-to-male PC sync connector. I connected it to my analogue camera (olympus om-1). The camera shutter fires the flash when connected via hotshoe. \$\endgroup\$ Nov 22, 2017 at 20:58
  • \$\begingroup\$ Oh, and I did try to reverse it and the same thing happens. I also tried to touch the inner circle of the plug in the flash with a headphone jack just to see what happens, and also, as soon as the jack touches the inner circle, the flash fires. \$\endgroup\$ Nov 22, 2017 at 21:00

2 Answers 2


Everything you are describing sounds like the cable you are using has an intermittent short in it.

It could also be a simple case of not having the cable properly plugged all of the way in either at the camera or at the flash.

The way flashes work is that the power to trigger the flash comes from the flash. The main pin on the camera's hot shoe is only a switch that shorts the ground (the rails on the side of the hot shoe) to the center pin so that the energy from the flash is allowed to return to the flash on the other side of the cable's polarity. The same is true of the camera's PC connector. When the shutter fires a short is created between the center pin and the outer ground that allows the energy from the flash to flow through it and back to the flash.


That is normal, or at least not unusual that it flashes when touched. That cable center pin is what flashes the flash, so primarily, that touch just says the flash and cable are working OK. Normally you would connect it when powered off, to prevent that.

Not firing from the camera shutter button is something else. Does your camera have any type of "Flash Off" menu or setting that could be prohibiting it from triggering a flash? Otherwise, it should always flash in A, S, M, or P modes.

However, some of the cameras Auto Scene modes (such as Landscape or Sports) specifically do not trigger a flash. If that might be the case, try another mode. More info about the camera mode might help.

  • \$\begingroup\$ Thank you both for replies!!! The camera is a manual-only SLR. I just realised I did not mention one thing. I connected the camera to the flash, and turned the flash on. After that, as soon as the cable moves a little bit, the flash would fire several consecutive flashes. Again, I guess it has to do with the contacts moving as the cable moves \$\endgroup\$ Nov 22, 2017 at 21:08
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    \$\begingroup\$ @RainForest - That sounds like there's an intermittent short in the cable, not shocking if it's cheap or old. Does it do this if you move the cable around (particularly near the connectors) while it isn't plugged into the camera? \$\endgroup\$ Nov 23, 2017 at 2:56
  • \$\begingroup\$ Yes, the flash fires even if the other end of the cable is not connected to the camera. \$\endgroup\$ Nov 23, 2017 at 10:04
  • \$\begingroup\$ That would confirm that the problem is either an intermittent short in the cable itself, or in the connector on the flash. You could further narrow down the possibilities by moving the free end of the cable while isolating the flash end from motion, first with one end plugged into the flash, then the other. Then try wiggling the plug in the flash without moving the rest of the cable. Hopefully that would tell you exactly where the problem lies. \$\endgroup\$ Nov 23, 2017 at 22:55
  • \$\begingroup\$ Just be sure to realize that if the PC cable connector center pin is shorted to its outer ring (like by using a paper clip wire, or a small screw driver blade, etc), the flash WILL FIRE, and is a signal that it works as expected. That is how the shutter triggers it, shorting that center pin to trigger it. Shorting the PC connector or cable, or shorting the center pin of the flash shoe foot (to the metal foot) will trigger the flash. Just plugging it onto camera might also do that, which is not in itself a sign of trouble. However, the camera not triggering it is a sign of trouble. \$\endgroup\$
    – WayneF
    Nov 24, 2017 at 18:59

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