yes not very good at this the m/c in question is a Marcy cross trainer unfortunately there is no model number on m/c, the power is a 6ooma plug set at 9v but had polarity wrong way round now tension not working hope this is better info
Assuming the power supply has not failed, you have probably blown something inside the machine.
An expensive lesson learned in not fiddling.
Do you know a **technically competent** person who could check?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix sports equipment.