If you are having problems with your SR250 you can call us at
If you wish to try and fix the problem yourself, the user manual may be useful, and the following troubleshooting guide may be helpful too.
1) Front-panel red overload LED is constantly lit
The front-end transistor (part number J310) in your SR250 Gated Integrator is most likely damaged and needs replacing. The reference designator is Q20 (located at G2 on the PCB). Before removing the damaged Q20, note its orientation: the silk screen legend on the circuit board may be incorrect. The new J310 must be inserted in the same orientation as old one. No calibration is required when replacing Q20.
You can order a new J310 by clicking here.
If you are still having trouble your SR250, it will need to come back to SRS for service. Click here to get an RMA number.