[R-390] More geartrain rebuild info

[Cecil Acuff]

Did we ever come up with a video or a series of pictures detailing the 
reassembly of the gear train.  I am faced with the prospect of rebuilding 
several over the next several months.  I have in the past been fortunate in 
being able to very successfully clean them without disassembly.  Gummout 
carb cleaner does wonders for cutting the crud.  That and simple green do a 
great job.  I re-lube with Mobile 1 synthetic motor oil in a syringe with 
the hypo ground flat on the sharp end.  Works great!

I would like to go through one using the disassembly method of cleaning to 
see if it is really to any advantage.  Even the split gears can be separated 
enough with a knife blade to blow the carb cleaner in...but I would like to 
try it the other way and get a good feeling for doing a full resync.

Cecil...
----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: "Barry" <N4BUQ at aol.com>; "R-390 HF Receiver List" 
<r-390 at mailman.qth.net>
Sent: Thursday, February 24, 2005 5:50 PM
Subject: Re: [R-390] More geartrain rebuild info


> Hi
>
> I very much agree that a gear train with a reasonable amount of crud in it 
> probably will require the planetary gears be torn down. When you do the 
> only way to really get them clean is to take them down to pieces and clean 
> each one.
>
> The obvious gotcha is how do I get these back together with only two hands 
> and a limited number of toes involved. Cleverly bent paper clips seem to 
> be the "other" way to do this if you don't have access to stuff like 
> plastic hemostats.
>
> Here's an issue that's a little more subtle. The gears probably left the 
> factory all nice and uniform. When they did you could swap any "top" with 
> any "bottom" and there would be no net effect at all. Over the years each 
> "top" has rubbed against it's respective "bottom" for a really long time. 
> Essentially you have created matched pairs of gear halves.
>
> So in addition to needing a number of fingers and toes to put it all back 
> together you also need three sets of eyes to make sure all the sets remain 
> with each other.
>
> The gear will work pretty darn well even if you randomize the gears. My 
> story is that it was a controlled experiment and I'm sticking to it. If 
> you want a silky smooth gear set when you are done it seems to be best to 
> keep everything in order ....
>
> Enjoy!
>
> Bob Camp
> KB8TQ
>
>
>
> On Feb 23, 2005, at 10:19 PM, Barry wrote:
>
>> List,
>>
>> In the process of tearing down this geartrain, I noticed the planetary 
>> gears
>> were quite clogged with grease.  Scott's slide show says it probably 
>> isn't
>> necessary to tear the planetary gears apart, but it didn't appear I would
>> get this one clean unless I did and I'm sure glad I did.
>>
>> Upon taking apart the three split gears, all three exhibited a fair 
>> amount
>> of drag when I twisted them against each other.  Upon closer inspection, 
>> I
>> could see small burrs on the teeth.  After removing these burrs, the 
>> gears
>> ride smoothly against each other.  I would never have known this unless I
>> disassembled them.  Also, it gives me a good chance to ensure a lot of 
>> the
>> hardened grease and dirt is removed.  After a 24-hour soaking in 
>> kerosene,
>> there was still a significant amount of grime in this assembly.
>>
>> Now if I can figure out how to get four split gears all tensioned and
>> reassembled at the same time!
>>
>> Barry(III) - N4BUQ
>>
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