Systemdek IIX problem

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yelworc
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Re: Systemdek IIX problem

Post by yelworc » 20 Aug 2018 00:11

I'm not sure but I don't know what else to do.
The voltage from the psu to the motor is 96V.

Maybe the resistance measurements (motor) are not correct...

willb
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Re: Systemdek IIX problem

Post by willb » 21 Aug 2018 14:41

Hiya,

Something like this would be ok (with your IIX pulley fitted) provided that you use the stepper pcb supplied with the motor. I agree with Abril that thise cap values look strange!
A 6k8 on a mains stepper seems very high, but then so are the cap values! But then 96v looks about right :(

https://www.ebay.co.uk/itm/Rega-Phillip ... Sw-ABbeasd

https://www.ebay.co.uk/itm/Rega-RP1-Tur ... SwmgJY26yh

These pcb's would be designed for 230-240v mains so should be fine for you.

The first motor (on auction), is off a Rega so will likely be the 31813 lower noise motor (which philips designed for TT's rather than general purpose). You can improve the stepper for these sllightly but the original works well enough. The 2nd one is a slightly cheaper motor used on basic Rega TT's and I think uses 0.39uf caps - but pcb is supplied for 240v.

Any decent 2nd hand philips/Premotec type motor will do the job and we can help out with Resistor/cap values as we've all used most of them over the years!

HTH

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 21 Aug 2018 18:58

Hi willb,

What do you think about these ones? - https://uk.rs-online.com/web/p/ac-motors/4410423/

https://www.newark.com/allied-motion-pr ... dp/76R0593

Am I right that the only difference between these motors is the price?

willb
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Re: Systemdek IIX problem

Post by willb » 21 Aug 2018 19:41

Hi,
Yes - they're both the same 31813 motor - the UK version of Newark (Farnell) are MUCH more expensive again! (typical uk pricing). RS are also in the UK.
You will have to research how much shipping costs are to find the best deal - the wonders of internet shopping :)

Cheers.

abril
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Re: Systemdek IIX problem

Post by abril » 22 Aug 2018 15:04

Would love to see the PCB layout of the Systemdek board to see what is going on??????

willb
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Re: Systemdek IIX problem

Post by willb » 22 Aug 2018 18:32

Hi Les,

From the photo's on page 1, it looks like 6k8 and 1uf in series, then 0.82uf in parallel. The 1uf definitely connects to the resistor and the 0.82 is across the red/blue motor terminals.

From memory, higher value caps tend to phase-shift (drop) less voltage than lower ones strangely! So that would make sense with the 6k8 (which looks something like a 7 watter).

I think Phillips claimed 0.82 was correct @60hz for the Airpax motors and 0.68 @50hz (which we now was bollards!). So he's probably got either a 31818 or 807 which should've been using 0.39.

But, 'dumb & dumber' award has to go to Linn for their 'mod' to the Valhalla board for the Airpax motors in the early 90's: instead of just experimenting to find the right value (as it's only single speed), they decided to leave the 0.22 in there, and added 2x68v zener diodes + a 12k resistor between them. So they 'pumped up' the 30 odd volt drop across the motor :shock: . If they'd just put in a 0.39 and set the trimmer it would've been perfect - trouble is, those boards are still out there being used with modern Premotec 31813's which only need the 0.22, so are not working anything like properly!

But you try telling 'em ' as the mighty Linn know everything (apparently).

Cheers.
LPT's running great still (must get a lid one day!)

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 22 Aug 2018 19:43

Would love to see the PCB layout of the Systemdek board to see what is going on??????

I don't quite understand what PCB are you talking about?

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 22 Aug 2018 19:47

Does anybody know how to remove the pulley from the shaft?

willb
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Re: Systemdek IIX problem

Post by willb » 22 Aug 2018 20:02

The pulley should come off the spindle with gentle upward pressure. maybe a squirt of spray lube will help with this.

As for the pcb - you posted several photos earlier:
https://www.vinylengine.com/turntable_f ... =50340&t=1

I've just tried to work out how the 3 components connect together by their relative positions.

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 22 Aug 2018 20:24

I've just tried to work out how the 3 components connect together by their relative positions.
I can take a pic of it later. Do you need it?

abril
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Re: Systemdek IIX problem

Post by abril » 22 Aug 2018 21:29

The track layout on the other side.
Got a pretty good idea how components are connected (I think) but it would be good to know for certain.
Plastic or metal pulley?
LPT's running great still (must get a lid one day!)
My DC'd LPT too.

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 22 Aug 2018 22:25

Plastic or metal pulley?
Metal

Alec124c41
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Re: Systemdek IIX problem

Post by Alec124c41 » 23 Aug 2018 03:51

Check for a set-screw in the side.

Cheers,
Alec

yelworc
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Re: Systemdek IIX problem

Post by yelworc » 23 Aug 2018 05:29

There's no set-screw in the side.

cafe latte
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Re: Systemdek IIX problem

Post by cafe latte » 23 Aug 2018 05:48

yelworc wrote:There's no set-screw in the side.
It might be hidden with a plug, either that or thread lock so gentle heating to soften.
Chris