Just wanted to make this knowledge available to others.
Our Whirlpool oven (model RDB306PDB7) crapped out the other day.
Thought it was the typical "thermal fuse" problem (thermal fuse goes
open and power is lost to the display/control). Took the front
display panel off and checked the fuse (have replaced it once or twice
before) and it was fine. NOTE: The thermal fuse ususally goes during
a cleaning cycle.
Well, now it appeared to the be circuit board. Looked it up and it
was going to be about $225 to replace. So, I took the circuit board
off and looked it over carefully. Here's what I found.
There's a power resistor (12 ohm) that is weakly soldered to a 1N4007
general purpose diode (standing in the vertical position) that had
come apart. Looks like they might have used some low temp solder that
couldn't take the continued heat and cleaning cycles, as well as not
creating a good mechanical connection first. I've seen similar
problems on my 1997 Chrysler Sebring Convertible dash display.
The power resistor is mounted in the air (for heat dissipation) but
the engineers didn't take into account the thermal transfer back to
the circuit board through the leads. Here's where I found that the
traces were lifted from the board from excessive heat.
I actually replaced the diode with a new one with longer leads so I
could bypass the etches on the board and used the longer lead to
replace the copper trace on the board (which I soldered much better
than it had been). The lead of the resistor that went through the
board actually ends up connecting to the display, so I ran a separate
wire to overlay the trace for additional thermal dissipation. I then
connected the resistor to this wire and the cathode of the vertical
Unfortuately, I didn't take any pictures but perhaps others with a
similar problem will be helped by what I found.
By the way, it's hard to believe the way this board was put together
meets UL requirements. Seems kinda' dangerous.