Also consider the SR series were billed as mobile rigs and you would not want a weighted free wheeling tuning in that application.

Ed, WA9GQK

On Saturday, April 26, 2025 at 09:41:46 AM CDT, Don Buska - The Radio Lab Works <don@...> wrote:

Thanks Paul,? I was wondering about the last of the SR-line.? So I guess once Hallicrafters went to the 'lighter' rig trend in the 1960's, no more Battle Ships, the flywheel was probably cast away.? I assume they went to clutch friction driving of the Kc, 100Kc and VFO capacitor on the SR-400A.? I've been working on the restoration of my SR-150 this past month and was kind of disappointed in the smoothness of slow tuning of the VFO, due to the friction clutch drive.? It tunes smoothly at the fast rate, but when your slowly working your way up or down you can feel the extra drag.? And I have cleaned the friction plates and drive disks.? I also lubed the brass bushing and VFO cap bearing as well.? Outside of completely removing the front panel and disassembling everything, I'm not to sure how good it can get.?? I'll need to test drive a few SR-400's and their lessor brothers to get a better feel I guess.

Thanks es 73
Don N9OO

On 4/26/25 9:01 AM, Paul Christensen via groups.io wrote:

Weighted flywheel tuning on my SX-25 and S-40a main tuning but not bandspread. ?SX-100 has weighted flywheel tuning on both main and bandspread. ?

No weighted tuning on my SR-400A, nor the matching VFO.?

Paul, W9AC.?