If you have no luck, these are good people I used to deal with. Call them. They had some Roto Hoe manuals online- but not yours.

Here is a link that might be useful: Jerry's

There is an older post about this. Do a search under roto hoe and you will find where they talk about the poor design of the belt tensioner. It almost seems that if you can put more pressure on the tensioner, you will have better luck.

I had a model 500 chipper shredder which I just sold - 5hp engine and not big enough for me. It did eat the belts - about one for every 4 hours of operation. Always kept a spare set on hand.

Other than the belt issue, no problems.

Good luck