Bosch HBL 73 Service Manual page 32

Tuesday, June 18, 2002
BOSCH 700 SERIES:
ELETTRODOMESTICI
SERVICE INSTRUCTIONS FOR OVEN TESTING AND BASIC TROUBLESHOOTING
VIA CHECCHI 98
I 21013 GALLARATE
ITALY
1. DISPLAY BOARD. Mounted on the front panel, it's the oven brain. It manages the user interface (VFD display, selection knob
and keyboard), receives inputs (directly from the field or by means of the Power Board) and sends information to the Power
Board to drive all outputs (heaters and auxiliary loads).
2. V.F.D. (Vacuum Fluorescent Display). It's mounted on the Display Board and is used to display information for users and
technical operators.
3. POWER BOARD. It's mounted on the cooling channel; it provides the Display Board with all its power lines. It manages the
latch mechanism, the heaters, the oven lights and the fans, according to the Display Board indications. It measures the
temperatures read by the RTD sensors in the cavities.
4. AUXILIARY RELAY BOARD. It's mounted on the front panel. It provides the Double Line Break feature for Canadian
requirements and, for the double oven only, the working fan high speed.
ND
5. 2 THERMOSTAT RELAY BOARD. It's mounted on the cooling channel, to by-pass the low temperature safety thermostat
during self-clean. See electric schematics to see how it works.
6. TOUCH KEYBOARDS. There are two different keyboard models, providing the single oven with 6 pads and the double with 8
pads. They are glued on the front panel glass.
7. HEATING ELEMENTS (nominal power at 240V).
a. UPPER ELEMENT
b. LOWER ELEMENT
c. RING ELEMENT
d. ADDITIONAL ELEMENT
SYSTEM PARTS
3500W
3000W
2500W
~1000W (Actually its nominal value is 775W at 208V)
Page 1 of 28