Linn Axis PCAS011 power supply

[waretweaker]

Hello, Klink! Me too, have a non-functioning Linn Axis motor/control board, then I would appreciate a lot if you could send the schematics to josepaulobrito@gmail.com . All the best, cheers, JPB

 

[waretweaker]

Hi again, Klinker! I already received the schematics, thanks a lot!!! ***** Cheers, JPB

 

[andreaIT]

Axis PSU

Dear all,

I also have a broken Axis PSU unit (everything stops when switching to quiet mode) since a few days.
I would appreciate very much to have the schematics from someone there.

Thanks very much
Andrea

 

[tkwou]

What is your email?

 

[andreaIT]

PCAS011 schematic

Just received from Klinker.
Thanks to you all!
Now I'm analysing...

 

[Peter Dolman]

Linn PCAS011 circuit diagram query

tkwou,

If you still need schematic I can e-mail it to you. Don't think this board supports file attahments.

Redart

Hello Redart from sunny Wiltshire, UK. Is there any chance you could kindly send me a copy of the circuit diagram for this? The servo board in the particular one I have here is marked PCAS011/L6.

My e-mail address is peterdolman@btconnect.com

All my best regards

Peter.

 

[Pyramid]

You can find the schematic on-line here: Linn Axis Schematic

 

[Peter Dolman]

Linn Axis servo info

That's a really useful link - and just what I'm looking for. Thanks very much for your help on it.
Peter 🙂

 

[tiefbassuebertr]

Many thanks to Redart and Klinker for your assistance. I finally repaired my Axis power supply but not without significant trials and tribulations. I certainly learned my lesson. Never embark on repairing a complex circuit without a schematic and doing your research first. I had just finished fixing my Valhalla supply so when my Axis supply died I assumed the similar parts had died. In restrospect I was correct. Replacing all the electrolytic filter caps, decoupling caps and coupling caps got the power supply working again but the motor would only start up and run for about ten seconds and then stop. Assuming there was still something wrong I proceeded to find out what. It was only after speaking to the Linn technician that I discovered that this was normal. The Axis power supply starts up at 70V and then switches to quiet mode after about ten seconds when the output drops to under 25V where it will stays until it detects load. Once a load is detected it will adjust voltage to keep the speed consistent, ie it will not run without the platter connected. Too little knowledge too late for me. While trying to figure what was wrong I accidently shorted the motor outputs. Many things blow when this happen. The surge protector blew. The power transistors for each motor winding blew. I replaced these items and the output circuit was up and running with all the right voltages but the ps still didn't work. I checked the low voltage circuit and I only got 2.2 volts across the 15V zener. I replaced the zener with no change. I knew something was badly shorted in the low voltage circuit. I hooked up a 12v ps directly to the low voltage circuit. The output opamp chip got real hot. I replaced the LM324 opamp and my low voltage went up to 9V. A bit better.
My V+ was now 9V but the V/2 was only 2.2V. This was traced to a short in the CMOS switch 4066 chip. Now the V+ was up to 12.5V. Then I replaced the other LM324 in the load sensing circuit and V+ was back to the normal 13.5V. The LED's lit up properly with the switch and I got 33 1/3 but no 45rpm and no response to load. The voltages at the motor seemed alright. The problem was the 10 ohm resistor that lifts the common winding off of ground. Well after all that I'm finally up and running again. Thanks again. Never would have made it without the schematic.

good reporting - thank you.
Check out my posted listening test between Linn's LINGO against this AXIS motorsontrol in post #12 under
Homebrew Motor Control Linn LP12 - Circuit Description wanted for Sine Wave Osc.
and post #69/70 for service helping under
Repairing Linn Axis Motor Drive Amplifier