Shutter not working with flash attached...why?

I have just started using flash in my photography and decided to purchase a

Jessops 280 AFC Flash Gun (canon dedicated) to use with my EOS 30.

 

The problem is that the flash is coursing the shutter to not work. I can be

taking pictures with the flash and then all of a sudden nothing. I press the

shutter button fully and the shutter and flash do not work .

 

The camera is still metering fine and focus is still working fine. The flash

ready light is on and I have only used it in manual mode with manual focus.

 

I know to fix this problem would be to get a canon flash but does anyone know

what could be happening. It�s starting to happen right when I need to take a

critical short!

 

Any input is welcome. Thanks in advance.

The first thing to do is measure the trigger voltage of the flash unit to make sure it doesn't exceed the 6v limit of the camera.<p>

According to Chuck Westfall of Canon USA,<br>"Excessive trigger circuit voltage can damage the shutter units and X-contacts of most modern 35mm SLR cameras."

<P>Just turn on the unmounted flash, and use a voltmeter across the side-contact and the center-bottom-contact.

Feel sorry to hear about your situation. Honestly, I don't know wha's wrong with your comobo. But I looked up the Jessops product, like the 400AFM, it's obviously poorly Chinese made flash. I would not recommend you to continue to use it or it may damage your camera, totally doesn't worth it-the body cost way more than the off brand flash! And for the EOS 30, you can use ANY EX flashes with E-TTL II technology, why count your shots on a off brand flash while a used 380EX is merely $80-100. Or even, Sunpak and Vivitar makes good flash, although it's nowhere close (quality and reliability) to Canon's flashes, but they would work, definitely better than the Jessops's.