Brand:GE Model Number: PSB1201NSS01 Main Symptom: Display flickers/dim What happens & when: When operating
Error Code (if any): none
Parts or tests already tried: replaced WB27X10856, Digitron
Photos / video link:
Original issue, display flickers and becomes dim; however, microwave still functions. Ordered & replaced Digitron, PN WB27X10856. When new Digitron is installed, screen is blank, buttons will not function, microwave will not function. Swapped old Digitron back, the screen flickers and is dim, buttons work, microwave works. Swapped new Digitron back in, screen black, no button function, no microwave function.
Did I receive a bad part?
Jeff, thank you for your input, it’s very much appreciated. It does appear as though I unfortunately received an inoperable Digitron. Thanks Again, John
If a second digitron fails to operate, there are voltage tests that can be done to identify what may be occurring. These tests can also be used to verify that the issue would likely be in the digitron or main control rather than with a different component. With the control panel wire connections accessible, the power PCB can be tested for DC volts from the low voltage transformer at connection CN7. With the black probe of a multimeter set to the brown wire at pin 5, there should be 12 Volts DC when testing the yellow wire with the red probe. There should also be 19 Volts DC when testing the white wire with the red probe. If the black meter probe is moved to the black wire at pin 2, there should be 7 Volts DC when measuring the red wire. If that checks good, the next step would be testing at connection CN 4. With the black meter probe at the wire on pin 15, the red probe would be placed at the wires from pin 1 all the way through to pin 12. The voltages should be 5 Volts DC at pin 1, 14 Volts DC at pin 2, 7.5 Volts DC at pin 3, 12 Volts DC at pin 4, between 0-5 Volts DC at pin 5, 5 Volts DC at pin 6, between 0-5 Volts DC at pin 7, 14.5 Volts DC at pin 8, 4 Volts DC at pin 9, 5 Volts DC at pin 10, 4.7 Volts DC at pin 11, and 5 Volts DC at pin 12. If that looks good, CN11 voltage can be checked to make sure it is sending proper volage through to the relay control (which also has a voltage connector to the main control). With the black meter probe on the black wire, there should be 15 Volts DC when testing with the red probe on the white wire, and 12 Volts DC with the red probe on the red wire. If that looks good, the main control would be tested using the connection CN4 and CN3. With the black meter probe at the wire on pin 15 of connector CN4, test the CN3 wires with the red meter probe. The wire at pin 3 should measure a steady 3 Volts DC while every other wire should fall in between 0-5 Volts DC. If the voltages all look good, then it is safe to say the failure would either be with the digitron, or with the main control.
There is one last check that can be done. On the relay control, test the two wires at connection CN1 for 120 Volts AC. If the voltage is good, the low-voltage transformer is not working properly, which can cause everything being seen with this appliance. If this turns out to be the case, unfortunately, it appears that the manufacturer has discontinued the low-voltage transformer based on what I see in this link. GE WB17X10021 Microwave Transformer Power | Genuine OEM Part
