The 06-DTC-101 is an external TEC driver manufactured by Melles Griot. The device was intended to drive TECs of various specifications in lab settings. The system supports various types of thermistors which are used to monitor the temperature and control the TEC based on a user-configurable temperature setpoint. A digital readout enables the user to monitor parameters such as temperature, setpoint, TEC current and current limits. Example use cases include regulating TECs for laser systems or optics that require precise thermal management.
Below are some specifications that we were able to pull from a PDF attached to a sales listing for this device. Unfortunately we were unable to find any official documentation on the device from Melles Griot.
- Maximum Output Current: 2 A (adjustable current limit: 0-2 A)
- Maximum Output Voltage: 8 V
- Supported Temperature Sensors: AD 590, AD 592CN, LM335
- Temperature Range: -20°C to 60°C (resolution: 0.1°C)
- Thermistor Range (high): 100 Ω - 199.9 kΩ
- Thermistor Range (low): 10 Ω - 19.99 kΩ
- Thermistor Resolution: 100 Ω / 10 Ω
- Input Power Requirements: 100-120 VAC / 220-240 VAC, 50-60 Hz
On the front of the unit is a large digital display that shows various measurements depending on the position of the selector switch. A power switch in the lower-left corner isolates AC power from the unit. After that is a rotary selector switch which changes the display readout and signal produced from the OUTPUT BNC terminal. It has the following selections: set temperature, current temperature, TEC current (I), and current limit. After that is a 10-turn potentiometer for adjusting the temperature setpoint. The last control is for the thermistor type, which has the following selections: THERM LOW, THERM (normal), LM355, and AD592. The OUTPUT BNC connector is for monitoring and data logging as it outputs the currently displayed value as a voltage (0-9 VDC). The rotary selector that changes what is displayed on the built-in screen also changes which data point is output from the BNC. On the top right corner is the COOLER ON button and accompanying status light, this allows the operator to disable the TEC without needing to shut the whole unit off. The thermistor readout remains active even when the TEC is off.
There is not much to see on the top or side of the unit. It's a nice aluminum case which feels very sturdy.
On the bottom are some rubber feet and kick-stands that can be extended to tilt the unit upwards on a workbench. The information sticker shows that the unit was manufactured in 1997 and has a relatively low serial number of 1075.
On the back are the majority of the connections along with some additional controls. There is a standard IEC power input with a fuse, and a separate selector switch for 120/240 VAC operation. There is a small cooling fan that we plan to replace as it sounds like the bearings are failing. There is a banana jack which is tied directly to the case ground, useful in ESD sensitive environments. The male 5-pin connector is for connecting the actual TEC and thermistor. We were unable to locate a pin-out for this connector anywhere, so we figured it out ourselves and provided a table below for reference. The TEMP ADJ BNC is for externally controlling the temperature setpoint. A two-position switch is used to select between PTC and NTC thermistor types. Lastly there are two small potentiometers recessed into the case that are used to adjust the thermistor gain and TEC current limit. In this particular unit, the current limit potentiometer was bent off to the side making the adjustment screw inaccessible from the hole. This was easy to fix as we just opened up the unit and bent the potentiometer back into place.
| PIN | FUNCTION |
|---|---|
| 1 | TEC |
| 2 | TEC |
| 3 | N/C |
| 4 | THERMISTOR |
| 5 | THERMISTOR |
Removing the 4 screws on the back panel allows it to be pulled away from the metal enclosure.
There is not much length on the wires, but it can be shifted down and to the right to allow the top section of the metal enclosure to slide off towards the back, revealing the internal components.
There is not much to see on the back of the board other than a small bodge.
Located towards the center of the board are two chunky transformers and some capacitors. The board is very cleanly laid out and features all through-hole components. It appears to just be a two layer board (front and back) and is about what you'd expect from the late 90s. Various types of operational/precision amplifiers, 74HC-series logic, analog switches, and transistors for driving the TEC all reflect a simple analog design. Luckily, all the components are clearly labeled and quite common. Repairs should be easy on this unit, especially since there is no central MCU or processor.
This is the display board that also includes the COOLER ON button. It mounts to the back of the front panel via some standoffs and connects to the motherboard via a ribbon cable. There's not much to see on this board other than the 7-segment displays and a TC7107RCPL 3.5 digit analog-to-digital converter which is used to drive the displays.
There are plenty of labeled test points on the board along with two internal potentiometers located towards the front. The potentiometers are labeled IC OFFSET and REF and are likely used for calibration, but we have no documentation to confirm this.
Connect a suitable thermistor and TEC, set the current limit and temperature setpoint, and enable the cooler. It's a simple unit that just works! It will even switch polarity and turn the TEC into a heater if the sensed temperature is too far in the opposite direction of the setpoint.