Help needed with Michell GYRO Dec Project

[Descartridge]

This may prove to be my most ambitious undertaking, a Michell GYRO Dec. Please let me know a source of parts and if you have any advice.

1. The Motor spindle is floating, not fixed in place. I do not know if this is intentional design. The issue has been solved.
   
2. The three spring adjusting supports are not functioning. That is, the aluminum sub chassis is not suspended above the acrylic plinth. The issue has been solved.
   
3. The protruding brass weights attached to the platter's bottom- touch the aluminum sub chassis. I need to check and see if the bearing is missing or do I simply replenish oil?The solution in in-progress.
   
4. One of the three feet is missing. I thought the stud was of metric threading; but a tryout proved incorrect. A new foot will be machined.
   
5. The caps covering the spring assemblies are missing. Caps will be fabricated.
   
6. The power supply is absent. I will probably build one. A hopeless case- a new motor is on order.
   
7. A Magnepan Unitrac tonearm is mounted; but the counterweight and the rod attached to the cwt are gone. I have a WTB ad on BT related thereto.

I will contact Michell later after receiving AK advice.
Thanks

 

[dean man jim]

You'll first need to get a manual for your model and learn it, and then practice setting the turntable up. In this, setting the springs tension and orientation are very important in order to get the proper bounce. I'm attaching documents that describe setup procedure with the Gyro SE (with pictures) and the Gyrodec (no pictures).

There is significant expertise at Vinyl Engine where there is a Michell forum. The library and databases there are very useful.

One source of parts is via Artech which is the US distributor. Some UK retailers also will ship to the US (Analogue Seduction was and still may be one of those).

This should help to get you going with this excellent LP spinner. Have fun!

Jim

 

[Descartridge]

You'll first need to get a manual for your model and learn it, and then practice setting the turntable up. In this, setting the springs tension and orientation are very important in order to get the proper bounce. I'm attaching documents that describe setup procedure with the Gyro SE (with pictures) and the Gyrodec (no pictures).

There is significant expertise at Vinyl Engine where there is a Michell forum. The library and databases there are very useful.

One source of parts is via Artech which is the US distributor. Some UK retailers also will ship to the US (Analogue Seduction was and still may be one of those).

This should help to get you going with this excellent LP spinner. Have fun!

Jim

Thanks Jim

 

[Beobloke]

From your pictures and description, it looks like your main problem is that the cups that locate the bottom of the springs are completely missing and so no wonder everything’s sitting on the chassis!

Don't be afraid to contact Michell directly for advice. They're a lovely bunch of people and are very helpful.

 

[Descartridge]

My motor see below is unusable per michell.
Anyone know the rpm needed for this deck?
i really hope that i will not be forced to part this gem out.
desperate and hoping...

 

[bang4buck]

If the pulley is present, you can calculate the RPMs needed for 33.3 at the platter. But what's wrong with the motor? Some googling tells me these rarely fail except for seized bearings, which can be repaired.

 

[Descartridge]

If the pulley is present, you can calculate the RPMs needed for 33.3 at the platter. But what's wrong with the motor? Some googling tells me these rarely fail except for seized bearings, which can be repaired.

i do have the motor pulley.
The motor is not seized, spins very freely and smoothly. According to Michell it required a custom 2-phase 3 wire power supply which is no longer available. (?)
thanks

 

[4-2-7]

i do have the motor pulley. Do you have an app or site to calculate rpm?

I can't see why you would need to calculate anything with you having the pulley and platter, of course you need a new belt.

It also looks like you have a platter mat on it from a vacuum hold down system that's not right at all. It would help a lot more if you took some more photos of individual part and get both sides so we can look to see what you have.

 

[bang4buck]

@4-2-7 please read all the posts

@RDecartridge Just measure the circumference of both platter and pulley. The ratio of the two is the same as the ratio between the speeds. Say the platter is 10 times larger around than the pulley, then the motor needs to run at 333rpm.

There is a fudge factor because the thickness of the belt comes into play, as well, but this should get you close enough to identify a suitable replacement motor.

 

[4-2-7]

Heres my thread setting one up, take a good look at the part inventory.
http://audiokarma.org/forums/index....ecnoarm-sumiko-blackbird-setup-photos.709440/

 

[4-2-7]

@4-2-7 please read all the posts

I did, what does that have to do with my comment?

 

[bang4buck]

He needs to know the motor rpm because he can't use the motor he has and is looking for a replacement motor that would drop in. So, unless you have a spec sheet for the Papst motor handy, we will need to calculate.

 

[4-2-7]

He needs to know the motor rpm because he can't use the motor he has and is looking for a replacement motor that would drop in. So, unless you have a spec sheet for the Papst motor handy, we will need to calculate.

I look at it as he has the motor, it might need some service like a bearing, but really what does "Floating" mean to him? He said he doesn't have a PS, but really you can find one of those if he doesn't want to make one. However this is what I'm getting without him being very clear and he hasn't ran power to what he has anyway.

Now you don't need to be so snooty and you might as well stop quoting me as well.

 

[Descartridge]

I look at it as he has the motor, it might need some service like a bearing, but really what does "Floating" mean to him? He said he doesn't have a PS, but really you can find one of those if he doesn't want to make one. However this is what I'm getting without him being very clear and he hasn't ran power to what he has anyway.

The floating issue is fixed. There were 3 rubber "feet" securing the motor flange to its top plat and 2 had failed.
Thanks

 

[bang4buck]

@4-2-7 I never quoted you.

@RDecartridge I take it you're in the US, right? So that 50Hz motor is of no use to you without a dedicated power supply that generates 24V 50Hz AC. At any rate, the Papst apparently spins at 3000rpm

Edited to correct: 1500rpm. The 4 in the part number is the number of poles. It's an AC synchronous motor so the speed is only governed by the line frequency and the number of poles. Gives 1500 in this case, according to smarter people than me on the web.

 

[Descartridge]

@4-2-7 I never quoted you.

@RDecartridge I take it you're in the US, right? So that 50Hz motor is of no use to you without a dedicated power supply that generates 24V 50Hz AC. At any rate, the Papst apparently spins at 3000rpm

Thanks and yes the 50hz motor is of no use in the US.

3000rpm???

 

[bang4buck]

No, sorry, I corrected myself. I found that number on a German forum but it was for a different motor, a 2-pole. Yours is apparently 4-pole so runs at half that speed, 1500.

Now I see that is in fact the pulley in your first photo, not an empty motor shaft. Very small diameter because it spins so fast.

I think you have three options. One is to find a power supply to match the motor and pulley that you have, but that's probably not cheap, if available off the shelf at all.

Another is to use a DC motor instead. The pulley diameter would be less critical with a DC motor, as the speed is not fixed. So you could use a generic pulley and simply adjust the voltage until the platter speed is correct. My Oracle is DC driven (as it happens, it's also a Papst motor) and this works very well.

Lastly, you could go for a more conventional AC motor, such as used by Thorens, Linn, etc. Those run much slower, typically 300rpm in the US, so you would need to get a larger pulley custom made.

 

[Descartridge]

Thanks, Buck.
You may have seen that I have an Alexandria in for repair so I may have a spare suitable motor is around.
Can you recommend a small, quiet DC motor for this application?

 

[bang4buck]

Sorry, no. I would look into the DIY section here, or more likely the diyaudio forum. Lots of people have built their own TTs and DC motors are popular because of the adjustable speed.

Origin Live will happily sell you their DC motor kit but that starts at GBP255. I guess a good chunk of that is the motor itself but still, that seems steep for what it is.

 

[bang4buck]

Here's the link for the OL installation on a Gyrodec. No affiliation, no personal experience. https://www.originlive.com/michel-gyrodec-motor-power-supply.html