Teardown, Repair & Calibration of a Keithley 2400 Source Measure Unit (SMU)

In this short episode Shahriar investigates the failure cause of a Keithley 2400 SMU. The unit powers on and responds to controls however produces no output signal. Further examination reveals that the VFD display shows no activity when the output is enabled; normally the measured output voltage and current are displayed. This failure points to a digital problem, potentially a failure in the analog board FPGA.

Upon close inspection the FPGA clocking circuitry appears to have a failed solder-joint. A quick re-flow of the affected part corrects the problem and the unit reports the appropriate readings. The unit is then upgraded to the latest firmware and calibrated using a Keithley 7510 DMM.

2 comments

  1. Alvaro says:

    Hi Shahriar, thanks for this great video. To help others, I share my experience. I have a 2401, which failed a couple of months after warranty was over. It went to top of scale in voltage, and indicated NaN in the measurement display. The unit had very little use. I send it to the agent here in Chile and wanted about USD2500 for the repair. When opened I found some very bad solder joints, about four IC pins in the air. After reflowing them and many suspects, the problem was still there. Yesterday I inspected again and found the 4 current sensing resistors cracked. I am sure this is the main problem

  2. Elodie says:

    Hi, your video is really interesting. I actually have a keithley 2400 but it doesn’t even power up and the fuse look ok… would you have any advices?

    thanks a lot

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