The heating elements are burnt out. where can I

I would guess that the element is burned out. As these are a relatively inexpensive item I would not waste a lot of time or effort trying to repair it. I hope this helps you. Thanks

Marvin Replacement elements are available from Quartz Infrared Inc for $17.95. You can order them directly here:
http://www.quartzinfrared.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Marvin

So you want to know how I fixed my problem with my heater. If so I like to offer you my "Premium Fix it Plan" for just $19.99. WHAT A DEAL..

Marvin replacement elements are available from Quartz Infrared, Inc for $17.95.
You can order them directly here:
http://www.quartzinfrared.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Marvin

There are links to the instruction manuals there as well. They include information of how to replace the elements.

Yes, I got my Marvin, model 500 quartz heater fixed, thank you. Please discontinue further communication.

Very simple to install the replacement element. Insert one end of the element into the bottom receptacle on either side, press the element down (it's spring-loaded), then slide the top of the element into the center opening of the top receptacle, push to appropriate side (the side of receptacle, same as the bottom), then release. Then do the same with the other element (if both are out).

(937) 653-7131 is the phone number of W B Marvin, according to my Google search. They should be able to help you get a new knob.

Returned to home depot. Fan was broken.

call jhonstone supply or united refrigeration

try this place - they have replacement quartz elements maybe you can find one here.
http://www.infraredheaters.com/quartz.htm