Linn Sondek LP12 - Hercules II motor speed controller.

[Turnip]

Hi folks,

Have one in, where pressing the 'on' button, a Red Led lights and the motor spins. Gather a second press should cause a Blue Led to light indicating a speed change, but it doesn't - Motor turns off.

The Hercules II motor speed controller is ludicrous in dimensions and cost, for what seems to be a simple job of synchronous motor speed control - Sort'a £200 a pop, though the Linn LP12 player itself costs rather a lot more.

Customer uses a Leak Stereo 20, so guess he's serious - Any thoughts ? - Chris.

[astracat]

hi turnip
not seen one of these but the wam forum gives some interesting reading on this turntable ,it suggests that one version uses crystal oscillators to adjust speed and another version uses the tone arm to change belt position on motor pulley,note twin windings on motor dont suppose may be one o/c as one 50hz other60hz loads of motors on ebay for this deck
regards
astracat

[Turnip]

Thanks 'Cat'

Gather the early motor speed controller used to burn out regularly (Note repair kits were available) then the Hercules II was introduced, using Xtals to count down with an incredible number of ancient chips and two or three power transistors doing something or other.

Noted the two motor feeds, guess possibly one drive and the other feedback ? - Who knows.

Almost tempted to slip in a two speed DC motor, as it's only a record player, admit a bit expensive, also noticed its drive belt was a bit slack - Bargain at £20 plus P&P.

Chap himself might feel £200+ cheap for a new Hercules - Chris.

Reading up on line, discovered that if the 'go' switch is pressed and held down for five seconds, Blue Led lights indicating 45rpm. Tried it where the drive belt fell off - Something it didn't do at 33rpm. Guess just a belt job.

Then guess not, as with new belt fitted turntable took 5 minutes to get up to speed with considerable vibration from the synchronous motor.  Tend to suspect said motor has a congealed grease issue so gave the top a squirt of switch cleaner where it then fired up to speed after 20 seconds, even faster when warm. However when cold it isn't the biz so suspect a new motor for £156.00 might sort it.

Bit the bullet and bought one - Seems the biz, bit expensive though.