How to open Project RPM 1.3/Genie Motor?

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JPM
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How to open Project RPM 1.3/Genie Motor?

Post by JPM » 13 Jun 2019 00:17

Anyone ever attempted to open up the motor for the Project RPM 1.3/Genie?

I want to crack it open and have a look at what's going on with the mounting, isolation and damping.

I'm currently using a Genie Mk 3 that is probably about 8/9 years old and the motor is excessively vibrating and audibly humming/buzzing for the first hour or two of use. It's a bit strange because once it has been running for an hour or two it reliably settles down into almost dead silence.

I've isolated the motor from the TT by placing it on top of a bag filled with salt that sits in the well of a heavy marble pestle, and the pestle/motor has been placed on a separate surface to the TT (which sits on it's own heavy Ikea butcher block). Speed is stable, so that's not the issue, and I've a new belt on the way just in case. Transference of any vibration to the plinth and platter has been mostly eliminated (except what goes through the belt). But the buzz/hum when music isn't playing has my OCD circuits firing up! Grrrrr!

I've used a few different project decks over the years and from experience I know that they can be fantastic decks .... IF you are willing to put some serious troubleshooting work into isolating and damping the motor. If not, they can be noisy little buggers, even using the commonly touted fixes for motor noise. I managed to get my old debut carbon motor so well damped (sorbothane and car sound proofing foam and adhesive materials lining the motor well, and isolated with further soundproofing foam and sorbothane under the o-ring screws and o-ring itself) it had really black silences and no noise emitting from it even within a foot with the platter off.

So I know this much from experience - really great potential in their decks, but they are absolutely half baked when it comes to motor damping and isolation.

Given that the genie motor can and does run dead silent after a few hours running, I want to tinker with the internal damping and isolation in the motor housing as I suspect it's the usual cut corner approach that plagues many of their entry and mid-range decks, and in those first 10 minutes of warm up it sets everything rattling which causes a vibration loop that takes quite some time to settle down and go quiet.

Soo....that's a really long winded way of asking if anyone knows how this sucker can be opened up without falling back on brute force and probably wrecking it!

All advice and thoughts received with open arms!

themisto462
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Re: How to open Project RPM 1.3/Genie Motor?

Post by themisto462 » 13 Jun 2019 08:20

I would suspect, that there are screws under the damping pad of the motor housing and it looks, that the pulley is press-fitted to the axle.

JPM
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Re: How to open Project RPM 1.3/Genie Motor?

Post by JPM » 13 Jun 2019 10:49

Thanks, themisto.

I'll take that pad off later today and have a look - I just looks like the upper/outer part of the plastic housing is clipped into place over the lower/inner part of the motor. It didn't come off with a bit of tugging and pulling and prying at it with a screwdriver, so I just want to be careful that I'm not going to break this in trying to get the housing off.

Yes, the pulley comes off the axle with a firm tug (there is a dab of glue on the op that needs to be scraped off first, but then it comes off with a tug), so that part is ok.

Thanks

JPM
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Re: How to open Project RPM 1.3/Genie Motor?

Post by JPM » 13 Jun 2019 23:28

Nope...no screws under the damping pad. Looks like it's just two pieces of moulded plastic clipped together, but it's not very pliant so I'm a bit concerned about cracking it if I force it too hard when playing around and trying to figure out how to separate the parts.

Bit annoying cause I'll bet there is some half baked damping going on and some likely less than ideal mounting. Project do use cheap motors so there is always some noise, but I know from experience that with enough effort and thought they can be wrestled into almost complete silence. Just wish it was easier to get at!!

JPM
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Re: How to open Project RPM 1.3/Genie Motor?

Post by JPM » 14 Jun 2019 00:47

So, for reference in case anyone ever needs to know, I managed to get it open. Top plastic upper of the case just clips on to the lower plastic base. Needs a bit of prying and force to get them separated.

As suspected, it's very basic inside with absolutely no damping of any description. The mounting has the motor incredibly tightly coupled with the steel arms on the base of the case. Those screws are not coming loose without a drill, so at least coupling is there. Listening to it, the motor on this is noisy enough.

I lined the plastic case with foam (no sorbothane or sound proofing material lying around today) and clipped it back on. Damped the noise down some, but here's where this whole design breaks down....the pulley.

It's a cheap piece of resonant plastic. Without the pulley on and the motor running in its enclosure, the motor is pretty silent now thanks to all the added damping I've added. But as soon as that pulley goes back on, it starts resonating and buzzing away....and that's w/o the belt, so it's not the axle and bearings.

Tried damping the pulley with blu-tac, but that added weight seems to strain it too much.

So a big part of the problem seems to be a cheap resonant piece of plastic for the pulley. Seriously, that's just silly design. For the sake of a few extra bucks, project could have killed all these issues on the RPMs.
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