Help Please: Need Suggestions on Roaster Repair

[WWWWVIEWS]

I am repairing a very old roaster that was last used in the 1980s. It was converted from electric to gas and can roast 3.5kg/batch.

Advice received elsewhere: "add new bearings, ensure all motors turn, and know that the drum needs hot air from some where and the burners need to have air pulled though the flame or heating source then through the drum."

I don't fully understand what's in italics.


Are there any other suggestions?
Thanks

 

[Musicphan]

Here is a pic of typical airflow in a roaster..

https://www.home-barista.com/forums/userpix/18800_capture.jpg

 

[WWWWVIEWS]

It says I need permission to access that link.

 

[Musicphan]

Hum... just google drum roaster air flow diagram... you can find a bunch of diagrams on google image search