[R-390] PTO Woes

[Bob Camp]

Hi

I don't know if they still have them, but for a lot of years Fair Radio 
would sell you a replacement PTO pretty darn cheap. It was a "pot luck" 
sort of deal so you might have to buy more than one. I seem to remember 
them being less than $30 ...

	Take Care!

		Bob Camp
		KB8TQ


On Feb 27, 2005, at 2:33 PM, Dennis L. Wade wrote:

> Hello all,
>
> 	I think I killed my PTO.
>
> 	Probable cause of death was excessive pressure on the shaft while 
> attempting to re-install the RF deck after cleaning and recapping. 
> Apparently the Oldham coupler wasn't aligned as I had thought, and 
> after the deck was installed, I turned the Kc/s knob and noted an 
> excessive amount of drag.  Upon inspection, the mis-aligned disk was 
> *tightly* up against the VFO shaft.  Next time I have to take out the 
> RF deck, the PTO is coming out first.  Ah, the wisdom of hindsight.
>
> 	Looking at the output on a counter, it wasn't near 2.45500 Mc/s.  (It 
> was over 3).  Turning the shaft clockwise brought the frequency *up*! 
> Running the shaft the other direction brought it down to around 
> 3..then back up..then down consistently in the manner it should.
>
> 	My layman's hunch says the corrector stack and/or the core itself it 
> toast.  I've never done it that I know of, but it almost acts like it 
> was run out beyond its 10 turn stop given its symptoms.  If I set it 
> now at 2.455, and call that turn 0, it behaves ok till about turn 6 or 
> 7 when the frequency goes amuck, jumping around hitting almost 6 mc 
> and then, around turn 8 settles back approximately the right 
> frequency. However, it reaches 3.455 mc/s in about 9.5 to 9.75 turns.
>
> 	I'm not up to rebuilding a PTO (See what happened when I took out the 
> RF deck?). Unless I decide to do an autopsy, I have available a 
> Motorola for someone who would like one to rebuild. :/
>
> 	Maybe someone would like to rebuild mine? :D
>
> 	Anybody have a good PTO available?  I'd like one with linearity 
> screws (as in the Cosmos) if possible.  I'd like to find one here, but 
> failing that...anyone have any experience with the "as-is" PTOs from 
> Fair?
>
> 	Also, please advise appropriate penance for killing a PTO.
>
>               Thanks,
>
>                Dennis
>
> Dennis Wade
> KG6ZI
> Carmichael, CA
>
> 	
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