Lakeshore 340 Temperature Controller Blowing Fuses

Thomas, basically the model 340 has developed an issue in the power circuit of the main PCB and has most likely caused the power transformer to overheat and short out the input windings causing the fuse to blow.

Depending on the age of your Model 340, will depend on what needs to be done. I suggest you consider sending the Model 340 back to Lake Shore for a repair which will cost $1683.00 plus shipping and normally is completed in about 2 weeks. However, I can tell you that depending on the failure, it is possible that a repair will not be successful so you may want to consider purchasing a new controller instead of spending $1683.00

If you want to return the controller for a repair, please contact us at support@lakeshore.com and provide the serial number of the Model 340 as well as your complete contact information. We will send you a Return Authorization with additional instructions.