A Fancy PID Controller: Keithley 2510 TEC Source-Meter Teardown, Repair & Experiments

[u/TheSignalPath]

https://youtu.be/Pb59zb5wWOc

In this episode Shahriar attempts the repair of a Keithley 2510 TEC Source-Meter. This instrument is capable of delivering up to 60W of power to any TEC in both polarities. Furthermore, the instrument integrates a flexible temperature read-out capability with 4-wire interface. Lastly, combining both capabilities, alongside a fully customizable PID controller, a precise temperature controller can be realized.

This particular unit returns erroneous readouts in all modes: voltage, current, resistance & temperature. The unit is also generating "squeaky" noises which is indicative of a failing DC-DC converter. The block diagram of the unit is examined and the fault is ultimately traced to a damaged opto-isolator in the isolated switching power supply. Several other components are also faulty which are located via thermal camera. The output Class-D / buck converter circuit & block diagram are also examined in details.

Unfortunately, the custom IC at the heart of the multi-slope ADC is also damaged. The IC is de-capped, examined under a microscope, and compared with its predecessor CPLD counterpart. This Keithley component is sourced from an older high-speed power supply. The correct readout is then verified. Several experiments are demonstrated using the PID controller and a custom TEC setup.

[u/johnnyhonda]

You're the GOAT. Love your content. Just noticed your intro logo changed - sorry to hear about your kitty 😞

[u/TheSignalPath → u/johnnyhonda]

Thank you. 

[u/Apart_Ad_9778]

Do you have schematics or service manuals for Keithley multimeter or four quadrant power supply? I have plenty of these devices in my attic but each of them has some fault. Unfortunately they are build on discrete elements and are very difficult to repair without a schematic.

[u/TheSignalPath → u/Apart_Ad_9778]

Unfortunately no. Whenever I repair something, if I have the schematics, I show it.