GyroDec Mk3 running slow, advice

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Joined: 04 Jun 2010 11:58
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GyroDec Mk3 running slow, advice

Post by anuenlil » 09 Jun 2019 09:15

Dear all, I recently and finally managed to acquired a GyroDec mk3 which hadn't been used for years. It has the inverted oil bearing, double belt, Papst AC motor and original (pre-QC) power supply.

Now, I find it is running considerably slow. Yesterday, I tried de- and re-assembling it following the Michell instruction manual. In order to address the slowness problem, I did the following:

-I bought some Castor 0W40 (which is what Michell used at the time of production, if I'm not mistaken), cleaned out any old oil, filled up the well again to c. 2 mm, and added a few drops on the ball bearing and top of the shaft before refitting the bronze housing over shaft and bearing ball.

-Cleaned the pulley and platter grooves with some isopropyl

-Tried rejuvenating the belt(s) by letting them simmer in boiling water for 10'

None of this makes any difference. However, looking at the powersupply I see at least two caps that are not leaking but have definite bulges. The power supply also has a slight hum. Which brings me to...

Question 1: Might the problem lie there? Or is there anything else you could think of? The Papst seems to be very silent.

Question 2: I am now thinking it might be best to have it service by a professional. I have a turntable tech whose services I have been using for years, who is a qualified engineer with lots of experience but who has never touched a Michell. Would it be ok to bring it to him, or best to try and find someone who has extensive Michell experience (I am not in the UK)? I.e., how dissimilar/complicate are these decks to any other?

Many thanks for your advice,

Posts: 68
Joined: 29 Aug 2012 19:40
Location: wales

Re: GyroDec Mk3 running slow, advice

Post by gwernaffield » 09 Jun 2019 20:22

here Is an answer off Michell with regards to the AC motor ,, The old AC motors have two sintered bearings. If they have dried out then they can be oiled but they won’t be the same as before they dried out, you might get a year or two before they will need doing again. You really need to strip the motor down to lubricate it because if you oil it from the top, it could make the motor noisy, as you will be lubricating the series of washers on the top of the motor and they can then begin to vibrate. You can try using something thin like ZX1 or WD40.

The best thing would be to send it to us, so we can then replace the washers and circlip etc. and give it a good clean out and lubrication.

If you are using a QC power supply with it, make sure you turn the QC off when not in use. The QC has a current path to keep the motor warm, over a long period of time this will speed up the bearings drying out.
or read this ... st.138995/

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