My Linn Axis is Sick. Please help fix

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reading through this thread, there is clearly an awful lot of expertise here on the Axis PSU, mine doesn't have the real obvious problems that bubbamc119 described but I'm wondering whether it is showing early stages of it, perhaps someone can advise please.
The tt starts up ok and maintains a constant speed but I noticed that if I start the motor without the belt on it stalls after approx 5 secs & just buzzes, if you give it a twist it runs for another 5 secs and stall again although with the belt on it runs ok. I believe the psu increases the torque dependent on the load so maybe this is normal behavoiur but have not noticed it before...any ideas?
 
thanxs tkwou, now I can spend my weekend doing something useful rather than looking for a problem that doesn't exist🙂

It's perhaps not completely relevant to this thread i guess but has anyone come up with a fix to make this psu default to "stop" when first plugged in instead of running the tt, it's a pain having to leave it unplugged in case blips on the power lines start it up
 
The power supply is triggered on by a change of flip-flop states. Unfortunately the act of plugging it in or any sudden power outage or surge can trigger the flip-flop. If this happens a lot you could get yourself a small UPS for a computer. This would prevent this problem and you will also get a number of extra surge protected sockets to protect the rest of your stereo system too. A great idea if you are in an area that gets a lot of lightning.
 
The problem seems to be a design fault in the psu, when you power it up you might expect the flip flop to be inhibited until the cct stabilizes or a reset as part of the sequence but Linn don't seem to have thought it through, I was away for a couple of weeks not long after I got the tt and came back to find it running....and very hot, apparently there had been a power cut a few days before.

I can see the ups idea would work, I have one and might give it a go, but just wondered whether anyone had "fixed" Linns design. I thought about it but haven't been able to get the schematics.
 
Hex48 said:
I was away for a couple of weeks not long after I got the tt and came back to find it running....and very hot, apparently there had been a power cut a few days before.

Same thing happened to me, so I inserted a switched power bar between the Axis and mains. Just keep the power bar turned off when you aren't spinning.

Jeff
 
Got the schematic now

TKWOU sent me the LINN AXIS schematic yesterday, and I have to say it's a wacky piece of electronics full of LM324 opamps and discrete components. I'm not suprised that it breaks so often!

Anyhow, if anone needs a copy, email me

PeterMoreton A/T/ hotmail.co.uk
 
well I got the schematic from peter (thanks for making it available tkwou) and wacky piece of electronics about sums it up. It will be interesting to see if the start on power up can be resolved without to much reverse engineering but I have a more pressing problem.
When I asked about the motor stalling after a few secs without the belt on I was looking for the source of a Vlf rumble on my axis,
its not audible and didn't become apparent until I put a sub on my system but at sensible listening volumes, using an unmodulated "rumble" track on a test disc there is a high output, very low frequency signal which is overloading the sub. the driver is pulsing at around 5-10hz and the output meter shows peaks of 100w
Main bearing seems ok and has right level of oil, belt & running surfaces are clean & look ok. Table is level and on an acoustic platform.
I tried resting a matchbox on the chassis and lowering the stylus onto it to see if the subsonic was via the motor into the chassis but it was quiet.
From the frequency I suspect the noise is motor generated, but not sure which way to go with this,
If it leads away from motor/psu issues I guess I should start a new thread but
anyone got any ideas?
 
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