My camera is canon eos 7d. Housing is old UK-Germany for analog slr custom modifyed. Until now I was only using one analog strobe in manual mode- Hartenberger 500. I recently purchased used and with broken battery- Subtronic gamma. I replaced the battery and it works! But there is a catch. Every strobe for it self works fine. When i plug them in both in than only one strobe fires. It doesnt matter what combination of connectors i use- the one that fires is allways Hartenberger. Any ideas?