[TenTec] Substitute PA final transistor replacement test successful

[Curt Benjamin]

I picked up a 546 Omni D, series B at Xenia that the seller said worked but had a stuck PTO so I figured it might be an easy fix and maybe something I could sell to a new ham who wants a starter rig for HF. I managed to clean up the PTO so it's all greased up with Super Lube and working great but I later found that the finals were bad. 

I have been saving a pair of PA finals from a VHF, low band Motorola Maxtrac for such an occasion to try out. Knowing that xistors that are designed to operate class C would probably not operate well with bias applied, I figured I'd try them anyway - heck, I suppose I could keep it a CW-only rig until I find some suitable xistors. 

Well, they are holding the correct bias current and it's transmitting 110W out, and getting good audio reports on fone. Not too shabby for a set of free finals salvaged from some old Motorola radios.
I still haven't checked it on a spectrum analyzer but I figure I'll take it into work soon and check it out when I get a chance. I suppose the IMD characteristics are inferior to devices that are designed for this application but if it's reasonably clean and legal, what the heck.

Curt, K8AI