Linn Lingo Power Supply. Chasing the Ghost.

Upgrading (or is it called downgrading?) Linn Sondek from Linn Lingo to Naim Armageddon power supply was easy. My local Linn dealer (Shelley’s Stereo) took care of everything. Letting go of Lingo has turned into minor nightmare

While keeping Lingo to see if I can live without 45rpm option, I managed to obtain Lingo schematics and Service Manual/Test Procedure. Big thank You!!! to  mmckernie  at pink fish media !

Full recap was the first step. Lingo board before recap:

Recap set, with new U7 and U8 ICs, as received from DigiKey:

Recap ongoing…

and done!

The fun part of calibrating output voltages for 33&45rpm:

Checking that phase shift at the outputs is exactly 90 degrees. To set oscilloscope into Lissajous pattern is always fun!

Double-checking output voltages when Lingo is under load:

Fighting the Ghost which was not there:

When bench-testing 45rpm operation, with Linn motor connected to Lingo but not installed on Sondek, the “problem” appeared. Motor would start OK, but once the voltage dropped from StartUp 90V to the Cruise voltage of 60V, motor would stall and just vibrate and buzz angrily! After doing everything I could to narrow down the problem (except, unfortunately, following Lingo manual and installing motor back onto Sondek) I bought a brand-new motor. Same thing: 45rpm starts OK, then stalls. Returned “defective” motor for a refund, bought another one from my dealer. Got a free tip to install motor first, then connect to Lingo. That is how non-existing problem of 45rpm stall without load got solved! The price of this “knowledge” is a few weeks of headaches, shipping to and from GB, and one ruined Sondek motor… Ruined… how?

Within those few weeks when I was convinced that original motor got bad, I carefully took it apart for inspection. Nothing was wrong with the motor, just another synchronous, low-rpm, low-torque, two-phase brushless thing. Exactly as promised here: 9904_111_31813 and available w/o pulley and cap from Newark. The only difference between 50Hz and 60Hz Linn motors is the pulley, as explained by bettermusic  at Linn Forum. In short, those living in countries with 220V/50Hz power need just Lingo and Lingo board to upgrade their Sondek.  However, if your power is 110-120V/60Hz, then you need Lingo+Board PLUS a 50Hz new motor. Because the one installed in your LP12 is a 60Hz motor!

The difference between “old” and “new” motors is explained here: Linn Forum

Photo of Linn Sondek motor in pieces: