Linn Lingo Mk1 toggles continously between stall and normal mode

I bought a Wilson Benesch Circle about 15 years ago. My local Linn dealer adapted a Lingo 1 (year of production 1993), this was possible because the synchronous motor is similar to the motor of the LP12. Everything seemed to work properly.
But last week I checked the output voltage of the Lingo. It starts with 95 Vrms (stall mode) and changes after a few seconds to 60 Vrms (normal mode). So far so good, but afterwards it toggles continuously between the two modes. If I removed the belt i.e. no-load operation of the motor or changed the speed to 45rpm, but the behaviour remains unchanged. In stall mode the motor produces audible and sensible vibrations, therefore in the moment it would be better to feed the motor directly with 230V line voltage. I found a complete circuit diagram of the Lingo 1 in this Forum, but did not understand the control circuit. Maybe someone can explain to me which parameter forces Lingo to switch into the stall mode? How can I find out if its a problem with the Lingo or the motor? Would a recapping solve the problem?

Regards
Martin
 

I bought a Wilson Benesch Circle about 15 years ago. My local Linn dealer adapted a Lingo 1 (year of production 1993), this was possible because the synchronous motor is similar to the motor of the LP12. Everything seemed to work properly.

But last week I checked the output voltage of the Lingo. It starts with 95 Vrms (stall mode) and changes after a few seconds to 60 Vrms (normal mode). So far so good, but afterwards it toggles continuously between the two modes. If I removed the belt i.e. no-load operation of the motor or changed the speed to 45rpm, but the behaviour remains unchanged. In stall mode the motor produces audible and sensible vibrations, therefore in the moment it would be better to feed the motor directly with 230V line voltage. I found a complete circuit diagram of the Lingo 1 in this Forum, but did not understand the control circuit. Maybe someone can explain to me which parameter forces Lingo to switch into the stall mode? How can I find out if its a problem with the Lingo or the motor? Would a recapping solve the problem?

Regards
Martin

Why don't you remove the Lingo and drive the motor directly from the wall - of course, with an appropriate dropping resistor and phase cap - and see how the motor behaves.

I suggest it will run perfectly ... proving that your Lingo is in need of a service. Unfortunately, this might be an expensive exercise. :(


Andy