[Yaesu] Yaesu FT-625RD VFO

[Rick Blank]

> Hi All. I am wondering if anyone knows of a cure for this problem....
> 
> The VFO on my rig has a certain spot where it wants to "roll" off the
> frequency.
> I am thinking it is something with the shaft but haven't looked into this
> yet. 
> Possibly a worn ball bearing..?
> Just wondering if there is something that can be replaced, or is it
> beyond help.
> Any comments appreciated.
> 73, George  ka3jwj@juno.com

George, it's been quite a while since I have even seen an FT-625, 
but, if they are like the FT-902 drive then maybe a TINY bit of 
lubrication may help...I have found a product put out by Rawn 
Chemicals that is great for lubing planetary ball drives, like the 
ubiquitous Jackson Brothers Ball Drives from England, that is called 
RIP 3.  Rip 3 is a heavy duty lube that sprays out of the can in a 
slightly higher viscosity than such sprays as Tri-Flow, etc., but, as 
the solvent present in the lube evaporate, the RIP 3 thickens. 

This allows the lubricant to penetrate into the mechanism, allowing 
it to slightly "soften" up the old lube, re-lubricate dry spots, and 
then, in about a day, thicken into a grease similar in viscosity to 
the original grease in the planetary drive.

I did the drives in a set of the Swan 600R-600T twins and they work 
beautifully, I have done this with a drive I put on a 51J-4, with a 
Yaesu FTDX-400 and it's VFO, and several others that have come and 
gone thru the collection here.  I have found that VFO creep has 
usually been from thickened grease and PROPER lubrication can help 
immeasurably.  DO NOT USE regular lubricants that do not thicken as 
there will be too little dampening in the drive and it will feel 
"rough".

I would try a couple of drops, of RIP 3,  into the drive, a drop on 
the ball bearings on the vfo, and then work the VFO from one endpoint 
to the other by turning the knob.....work the lube in a drop at a 
time, when the drive loosens up and has no more backlash, STOP....let 
it sit overnight, run it from end to end again, and all should be 
well....I have a syringe that came from filling ink jet cartridges 
that works excellently for applying a small amount of this lube after 
you collect the RIP 3 spray in a suitable container...clean up with 
mineral spirits or equivalent...

I guess that if RIP 3 is locally unavailable that one could 
experiment with using motorcycle chain lubricant...these usually foam 
on, clean out dirt, and then thicken with a high shear strength 
lubricant that is quite viscous and may work well in these kind of 
drives....Lubriplate lithium grease is TOO THIN to use in these 
drives, I have tried it and the results are poor with a very bad, 
rough, feel to the reduction drive....the original lube is much more 
like automotive chassis grease or non-fibrous wheel bearing 
grease....

Just my thoughts, I hope this helps.

73


Rick Blank, KI5SL                      rblank@txdirect.net
2223 Blanco Road
San Antonio, Texas 78212

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