Who is interested in a groupbuy of Mark Kelly's DC controller PCB and related parts

[Mark Kelly]

OK here are images of the silkscreen for the controller board :



And for the adjustment board:



They are connected via the three pin connectors at X4 and X6 .

[Mark Kelly]

More detail at

Web page on construction of kit

Which will be progressively updated with phots etc.

[john2]

Please put me down for both boards plus any componants. No motor. I will pay via PayPal-if that's OK.

Many thanks

[Bas Horneman]

john2 and anyone else who has shown interest:

I'm collecting the paypal email addresses for Mark Kelly.
The MK groupbuy is for pcb and if you want, the parts as well.

PCB:20 us$
PARTS:80 us$

In the header of your email please put "Mark Kelly Controller"
Please send me your

DiyAudio username:
Paypal address:
Amount of PCB:
Sets of parts to populate the PCB's:


Once I've got them all together I'll forward the data to Mark Kelly.

The Motor (and Pulley?) Groupbuy is handled by: superhkm

PS...very few have mailed me their paypal address?

[superhkm]

Originally posted by Bas Horneman
john2 and anyone else who has shown interest:
....

The Motor (and Pulley?) Groupbuy is handled by: superhkm

I'm sorry Bas, but I'm unable to source a pulley, unless I get one machined in a shop. Craft in Norway comes at a price, so I would be surprised if I could get a good one. If someone (You ;Bas ?) could post a section sketch of an appropiate pulley , I could give it a go with a skilled professional I know of.


Everyone:

The Motor Is Maxon 110191
Shipping included:

USA: 115us$
EUROPE: 106us$

You may notice that I put on an extra $2 , this is because I forgot I have to pay to get the motors shipped to me.

In the header of your email please put "Groupbuy Motor"
Please send me your

DiyAudio username:
Paypal address:
Number of motors


Thank you.

[markgall]

Yes, I also would like to see a pulley sketch or specifications. I may have to give it a go myself.

Mark

[Vinyl-Addict]

Originally posted by markgall
Yes, I also would like to see a pulley sketch or specifications. I may have to give it a go myself.

Mark

The pulley design is not so simple because of the mounting scheme of the Maxon motor. The mounting holes threaded into the motor body are on a rather small bolt hole circle so if your pulley diameter is larger than 0.500" (12.7mm), the pulley body will interfere with these mounting holes and a more complex pulley has to be machined. I say this in case you opt to press fit the pulley to the motor shaft and need to remove it for any reason. You may find that you cannot.
What type of belt do you want to use, flat, round, tape?

This is an image of my Maxon DC motor assembly I use with Marks DC drive.
Look closely at the where the pulley outside diameter overlaps the mounting screws for the motor. I use 2 set screws on my pulley for easy removal.

[Lord Dubious]

Hi All
I have a few dumb questions.
I hope Mark or Vinyl-Addict can help.
1. Are the mounting screws for the motor the ones that appear to be countersunk into the circular lid of the motor housing? Is it OK to cover the mounting screws? If so, would it be OK to use a pulley of greater diameter? Then, to access the mounting screws, one would only have to remove the pulley.
2. What would be the heaviest platter that the motor/controller could reliably turn without undue strain?
3. Vinyl-Addict, what type of belt are you using?
Cheers

[Vinyl-Addict]

[QUOTE]Originally posted by Lord Dubious
Hi All
I have a few dumb questions.
I hope Mark or Vinyl-Addict can help.
1. Are the mounting screws for the motor the ones that appear to be countersunk into the circular lid of the motor housing? Is it OK to cover the mounting screws? If so, would it be OK to use a pulley of greater diameter? Then, to access the mounting screws, one would only have to remove the pulley.
2. What would be the heaviest platter that the motor/controller could reliably turn without undue strain?
3. Vinyl-Addict, what type of belt are you using?
Cheers [
QUOTE]

I'll see if I can answer questions 1 & 3 for you. Mark will have to address #2.

1) Yes, you are correct. They are c'sunk for M2 x 0.4mm Flathead screws. As long as you don't press fit a pulley larger than 12.7mm O.D., the screws are removable without taking off the pulley. Larger than 12.7mm, I recommend you use opposing screws on the pulley.
You may be able to fudge a little larger, that's your call. Maxon has a very well documented PDF file you can access that tells you every dimension on the motor.
My pulley, as you can see, does slightly cover the screw heads.

3) The belt I am currently using is one I purchased from Turntable basics for $10. The P/N is FRM38.8. It is the longest or largest in circumference they sell. BTW, my platter is 12.240" (311mm) in diameter.

I am going to try a Mylar belt soon to see if there is a change in performance. My turntable is going through major changes in platter mass and a pretty involved inverted bearing so I want to see if mylar is a better option than a flat rubber belt. Feel free to ask any questions you like.

[Bas Horneman]

I asked Brian Cherry if we might be able to use his pulley's as used for the BIX and asked if drilling out the existing hole was/is a possible solution

This is part of his answer

the under rated pulley gets his 10 minutes of fame.
All the pulleys I've measured have runout. And this problem can be vastly worse on the sound than motor speed control. I've talked to machinists and they say it is impossible to make the pulley and then drill the hole perfectly centred. It must be done by small parts machine maker in one step process- hole and CNC body together. Also the hole must be slightly tapered to press fit. I suggest slightly barrelled with V groove top and bottom to use both thread belt (dual maybe) and tape. I've tried China, Singapore, Thailand and best result was Singapore, 2 out of 5 acceptable. A famous North American company refused to do it.

So I have yet to find the definitive solution. I thought it was just me but I've been checking other companies displays at shows and they have the same problems.

Ok that was the "bad" news. Now for the good news

I was talking to a supplier yesterday who does small precision parts for cameras and seems he is willing to try. DO you have a drawing for your pulley and how many do you need?