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Motor noise diagnosis
Posted: Sun Jan 17, 2010 6:41 pm
by Brad
I need a little help diagnosing some motor noise. I replaced the main spring in my recently aquired Standard Model A and there is nasty noise that I can't seem to adjust out. It appears to be coming from the governor assembly (GA). The GA shaft has pins at both ends. On end goes into a hole in the motor frame casting, the other goes into a hole centered in a tapered pin that his held in motor frame. See the pictures below. This tapered pin fits loosely over the GA end pin and one thought is that the noise is coming from this free play. The tighter I adjust this tapered pin against the GA, the lower the noise, however, I cannot totally eliminate it without affecting how freely the motor turns.
The other thought is that there is some damage to the spiral groove gear (worm gear) in the governor shaft. I looked closely at this damage and it spans a few grooves and there appears to be some metal missing, however, underclose inspection with a magnifying glass there does not appear to be any metal pushed into the groove, just metal missing and the grooves are all present. I am now thinking that this may be source of the noise as it is present regardless of speed of the motor.
So look at the pictures and watch/listen to video's and give me your expert opinion as to what I need to replace, or how to silence the motor (short of not running it

)
[youtube]
http://www.youtube.com/watch?v=AsrHIfGMb0Q[/youtube]
[youtube]
http://www.youtube.com/watch?v=r1SoMScM5Cg[/youtube]
Loose fitting pin in pin candidate for noise?
Re: Motor noise diagnosis
Posted: Sun Jan 17, 2010 7:28 pm
by Edisone
I just checked my 2 A machines, which are in pretty good condition - they both sound the same as yours. When actually playing a record, I really can't hear the motor, though .
ps - For the reproducer, you need to buy gasket tubing. It just tucks in around the rim, and holds fine.
Re: Motor noise diagnosis
Posted: Sun Jan 17, 2010 8:45 pm
by Lenoirstreetguy
You might try moving the governor a bit further to the left( as we see in in the vid.) The gear that meshes with the spiral might be grazing the governor spring collar. I had this problem when I redid my Victor III.
J
Re: Motor noise diagnosis
Posted: Mon Jan 18, 2010 8:31 pm
by Brad
Lenoirstreetguy wrote:You might try moving the governor a bit further to the left( as we see in in the vid.) The gear that meshes with the spiral might be grazing the governor spring collar. I had this problem when I redid my Victor III.
J
Thanks J, I checked that early on and verified it to not be the case.
The more I think about it I must be the damage to the spiral gear on the gov. shaft.
Re: Motor noise diagnosis
Posted: Sun Jan 24, 2010 10:51 am
by Brad
I spent some more time adjusting the gear on the spindle shaft along with the other items I could futz with and nothing I did improved the noise. I believe that I also convinced myself that the small damage to the spiral threads are not the cause.
The governor shaft has a pin on each end as shown in the first picture of my original post. The pin near the brake plate fits inside a hole of the larger tapered pin shown in the picture. the pin on the other end fits into a hole in a small plate that is attached to the motor frame.
What I did discover is that Both of these attachment places are very loose, that is, the holes are bigger than the pins and the governor assembly can be wiggled side to side (or up and down) at both ends.
What I belive now to be the cause is the governor assembly flopping around due to there only being 2 weights resulting in an unbalanced scenario.
So here is my question: What is most likely to be the cause: The pins on the governor shaft are worn down or the holes that these pins mate to are worn and elongated?
Re: Motor noise diagnosis
Posted: Tue Jan 26, 2010 12:03 am
by wjw
I vote that the pins would be worn since they are the moving part in the assembly getting lapped down by the stationary grit in the bearings.
Re: Motor noise diagnosis
Posted: Tue Jan 26, 2010 12:19 am
by Energ15
Sometimes I have heard noise from my motor when it goes to fast. I think it's coming from the governor shaft too. I think it might be the pin.
Re: Motor noise diagnosis
Posted: Fri Oct 29, 2010 12:50 am
by SonnyPhono
Hey Brad,
Did you ever fix this problem? If so, how did you do it? I have a motor I am working on that sounds identical to your videos. I checked the pins on the GA and like yours, they are a bit loose where they fit into the bearings. I don't know if I need another governor shaft of if I need new bearing pins with smaller holes.
Any ideas?
Re: Motor noise diagnosis
Posted: Fri Oct 29, 2010 12:40 pm
by Brad
Hey Sonny,
No I haven't. I now believe that the pins/holes are indeed the cause. I found that if I put some downward pressure on the GA at the pin point things quiet down, although speed regulation is lost. This downward pressure is in effect preventing the GA ping from "flying around" in the hole it spins in. What I don't know: is it the pins or the receptacles? I would assume that the receptacle sides are made from softer metal so it is probably there. I have been looking for a replacement motor for either parts or a whole motor. No luck so far.
If you solve your issue, come on back to this thread and let us know you you found.
Re: Motor noise diagnosis
Posted: Fri Oct 29, 2010 6:36 pm
by SonnyPhono
Brad,
What you have described is identical to what I am experiencing. There seems to be enough play in the governor pins that when it reaches full speed, the whole GA must be vibrating in the pin holes. I had also tried to put some weight on the governor shaft to see if it would help. It did help the noise by stopping the shaft from vibrating, but resulted in restricting the movement causing it to slow down quickly.
I don't know what to do now. I had a spare motor laying around for the same phonograph so I tried to use some of it's parts to replace those on the machine in question. It didn't work though leading me to believe that what you determined as the problem is correct. So how do we go about fixing the pin holes? Would there be a way to put some solder in the hole, then heat it up again while inserting the pin? Or would that bond the two pieces for good?
There has to be a reasonable way to fix this problem?