Where does tension spring go on edv 505 dryer

I have fixed a lot of these Dryers with that same problem.
The control board needs three relays to be replaced.
You need to get the same type relays.

hope this will help see the pic

Clean out your vent before calling a repair man.

put the belt onto the tension pulley first then use the large diameter drum to assist you in in LEVERING the belt on with tensioner spring in place . Failing that remove and replace spring with vice grips (put spring back on as it came off ).

https://www.youtube.com/watch?v=7jY609cz9-A

Slide-wear adjuster screws are located on top of the movable readout head. They are quite tiny and require VERY little adjustment. May take several attempts to get the "feel" of drag that you like, but repeatability can be "dead-nuts" when adjusted correctly.

Hope this helps,
Dolf-

Check closely where the idler bracket was at and also the spring location.
You look for a worn area on the frame of the dryer and also the worn area on the idler arm bracket. Once you locate the right place for them to go, then put your spring on and check to see where it may hook up, there should be a small worn spot to look for...Just remember that the spring will be under tension when it is hooked up. So look for an area that would be worn with the spring stretched out somewhat.
I will send you a website to check also, they have schematics of dryers and they may be able to show you the approximate location of the bracket.
http://www.partselect.com/ or try this one...
http://www.appliancepartspros.com/index.aspx
Good Luck,
I hope this helps.

here you go

Looking from rear of dryer,one spring on motor is for tension,therefore put belt around drum(groove to the drum surface).Then rotate the motor firmly clockwise tensioning the spring,take belt from right of drum over tension wheel then put grooves of belt on shaft of motor.Release motor to tension spring,job done !!!!!

there is a spring-loaded belt tensioner pulley. make sure it is part of the belt loop. you will need to move the tensioner pulley against the spring force then place belt on tensioner pulley and then release the tensioner pulley and belt will now be tight.