[R-390] R-390\URR Geartrain Problem

[hackmohr at myfairpoint.net]

Hello All,

It's been a year and a half since I last posted here. It took that long but I finally found the spare parts I need to continue a R390\URR rebuild. I've got the RF Deck out again and a mostly complete spare deck for parts. I have some questions about the mechanical side of things. I'm not a gearhead so I'll try and keep my nomenclature as accurate as I can.

There are 2 inner cams on the 2nd variable IF camshaft which control the motion of the 1st IF can rack. These cams have a rounded convex side, a sharply pointed peak, and a rounded concave side. The IF can rack rollers on both of my decks have no problem traveling up the convex side to the peak and down the other side. But reversing the geartrain movement, the rollers get stuck on the concave side of the cams and are unable to travel over the peak. The cam edge is almost vertical and presses against the rollers rather than allowing them to travel up and over. The geartrain drags down as the camshaft spins inside the gear. On both decks the gear clamp screw is stripped and unable to tighten around the camshaft. (As if countless techs have tried to fix the problem by just tightening the gear clamp enough to force the rollers over the cams)

I haven't yet pullled the IF can rack apart but I'm assuming that the rollers stuck against the cams is something that can be adjusted out? Any help will be appreciated. Thanks.

Mark
WA2FXM