Troubleshooting and repair should only be attempted by qualified personnel;
Review Safety Warnings Page for more complete details of potential hazards
Inside the enclosure there are lethal AC voltages, 15VDC power at 16 amps, as well as exposed rotating fan blades and other potentially hazardous components.
ALWAYS USE CAUTION! DEENERGIZE EQUIPMENT PRIOR TO ATTEMPTING SERVICE!
The display and LEDs will indicate what the on-board computer thinks is happening.
Verify that the unit has commanded the response before going in to verifying hardware. For example, verify the board indicates that the pump relay is closed before physically pulling the relay.
Peltier Elements
Troubleshooting Peltier elements can be difficult at the part level without specialized equipment. A conventional Ohm Meter will not provide useful information. Peltier failure or degradation can be indicated by current measurement. The measurement should be made during the first few minutes of start-up. For the M325D, the Peltier elements are wired individually. Unit-to-unit variation, such as exact voltage, wire run length, ambient temperature, and cooler temperature, can generate some variation. Testing can be performed by placing a DC inductive ammeter around the black or white leads coming off JP10 or JP11.
Properly functioning Peltier elements should draw between 6 and 9 amps each (with the cooler at room temperature; which is maximum loading). Greater than 9 amps indicates a partially shorted Peltier; Less than 6 amps indicates a partially open Peltier element. In either case, retest before replacement to verify results are consistent.
12VDC Cooling Fan
There are two regulated outputs for the 12VDC cooling fan, one is thermostatically controlled by the control board. The 12VDC cooling fan on a 125D should be wired to the designated 12VDC output of the board. Care should always be taken to avoid rotating blades!
| Symptom | Diagnostic | Fix |
| No LED(s) and no fan. |
AC power input. 5A AC Input fuse in Power Supply (remove PS cover to locate) Verify 15VDC at output terminals on Power Supply |
Ensure that AC power is connected. Replace fuse as necessary.
Replace fuse as necessary.
|
|
LED(s) on and heatsink fan does not run. |
Check fan for blockage (power off). Check for power at JP1 (AC power input, unfused). |
Clear any blockage, replace fuse or repair wiring as required Check fuses on control PCB-
|
| Failure LED is on. | Thermistor connection JP15 pins 1-4 |
Ensure proper connection.
If not, board is defective. Replace as required |
|
Impinger frozen and cooler indicates ambient temperature. |
Thermistor placement in heat exchanger block. |
Verify placement of thermistor Trace wiring to ensure wiring is not shorted to chassis ground due to pinched wires caught in covers |
|
Impinger does not reach set temperature but is below ready temperature. |
System loading. Verify Peltier Element current draw |
Ensure system loading is not exceeding cooler capacity. |
| Ready LED does not come on when impinger is below 10°C. | Ready temperature adjustment. | Consult Factory |
| Water carryover in system. | Impinger temperature. Should be below 5°C. | Ensure system loading is not exceeding cooler capacity and ambient conditions are not exceeding specifications. |
| Slip LED does not come on. | Water carryover in system.
Water slip sensor connections. |
Ensure system loading is not exceeding cooler capacity and ambient conditions are not exceeding specifications.
Replace sensor as necessary. |
| Pump does not start. Ready and slip LED(s) are on. | Pump electrical connections. | Ensure proper connections. Possible defective pump; Measure voltage at corresponding pump terminals.
Possible defective relay coil or relay contact- Visually check operation and condition. If O.K., check coil of relay with ohm meter; if O.K., possible bad relay contact; Replace with known good relay. |
Download Baldwin™-Series Model M325D Thermo-Electric Cooler User’s Manual