No heat
Parts commonly needed when your Samsung ovens & range has this issue. Recommendations are based on repair patterns and may not diagnose your specific problem.
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Parts
1Part numbers confirmed across multiple retailers for NQ70M7770DG
Repair tips for this issue
From the service manual for Samsung DOC30M977D Series Ovens & Ranges (2017)
From the service manual
Good to know
5 technician insights for the Samsung DOC30M977D Series Ovens & Ranges (2017)
C-F0 vs C-F2 Troubleshooting Priority
C-F0 (Main-Sub communication) usually indicates a connector issue on the Sub PCB side, while C-F2 (Touch panel communication) is more likely a ribbon cable problem - always start by reseating the Sub PCB connectors first, as this resolves 80% of communication errors
DLB Relay Stuck Behavior
If C-21 temperature high errors persist after sensor replacement, the DLB (dual load relay) or bake/broil relays on Main PCB are likely stuck in ON position - tap the PCB gently with a plastic mallet while power is off to sometimes free a stuck relay before declaring PCB failure
Door Lock Motor Resistance Variance
Door lock motors that measure 1200-1600Ω (below the 1600-2200Ω spec) will operate but lock/unlock speed will be noticeably slower - these are degrading motors and should be replaced soon to prevent complete failure mid-cycle when door needs to unlock for safety
Main PCB Surface Inspection
Before replacing an expensive Main PCB, use a strong light and magnifying glass to visually inspect for burnt resistors, cracked solder joints, or corrosion around connector pins - visible damage often indicates the PCB is truly failed, while clean PCBs that test bad are often just loose connections
Seeing an error code on your display? Look up your error code → for more specific diagnostic information.