Panasonic SD 251 bread-maker

[N_Cook]

Not my usual area of repair but change as good as a rest ,they say
Schematic not in the service manual , well not the one on
http://servicemanuals.pro/servicemanuals/index.php?find=http://disk.ka
relia.pro%2Fg%2Fgenard%2Fservice_manuals%2Fpanasonic%2Fhome_appliance%2Fkad0
105444c3.zip

I've never used one so am unfamiliar. Is the motor function separate from
the heater function - I assume so, both are failing to operate it would
seem. Unit was working fine and then failed to start one time. LCD and
option selections work fine, press Start , the red LED goes on but then no
motor or heater and no Err in the LCD display.
Fuses and wiring ok, seems to have 2 control lines through the interboard
ribbon , one to a relay for the heater and one variable one to a triac for
the motor. All associated minor components seem fine testing cold (no
isolation Tx here , everything hanging off the mains), no hot spots. Solder
to main 64p SMD seems ok. Not full of cooking grime
What is a supercap doing on the power board , not connected through the
ribbon to the control board, some relay hold-off or hold-on funtion at
switch off for some safety reason , rather than memory retention ?

 

[N_Cook]

Looks like it was corrossion on the ribbon connector or another connector,
the rest is probably RTFM.

Supercap is connected to p51 and p54 of the 64 pinner so probably retains
memory for a maximum of 10 minutes of power outage.
Then from the manual there is a "Resting" stage where the heater comes on
for a second twice a minute unless you warm the bucket temp sensor with hot
air. Similarly selecting "Dough" the oven has to be up to some temperature
something like 25 deg C before the motor/kneding action starts.