GE JS998 Series Technical Service Manual page 38

To turn off all loads that are energized in COOKING LOADS, press the CLEAR/OFF key or exit the
COOKING LOADS menu.
• If load is not turned off, additional loads can be turned on at the same time.
• If AC voltage measures OK, then check the load (element, fan, lock motor, HVT, etc.) and/or wiring to
the load and repair/replace as required.
• If there is no AC voltage supplied to the load through the power relays per the wiring schematic, then
check the DC power supply voltages from the main power board (MPB-J3 connector) to the main
logic board (MLB-J5 connector) according to the following table:
MPB MLB
J3-1 J5-1
J3-2 J5-2
J3-3 J5-3
J3-4 J5-4
J3-5 J5-5
J3-6 J5-6
J3-7 J5-7
J3-8 J5-8
J3-9 J5-9
J3-10 J5-10
J3-11 J5-11
J3-12 J5-12
• If voltages do not measure according to the table above, replace Main Power Board.
• If voltages measure OK, then measure DC voltages according to the previous relay control table
(relay control signals columns 3, 4 and 5).
• If the MLB J3 pins do not provide the correct DC voltages, then replace the main logic board.
• If display is blank, the oven light does not operate when the oven door is opened, and the keypanel
does not respond, first check DC power supply voltages. Next, check DC voltages at MLB J2: J2-2,
J2-4, J2-6, J2-8. They should be +12VDC. If not, replace text display and/or time/temp display.
• If DC power supply voltages are OK, the display is blank, and the keyboard is not responding,
replace MLB. If just the display is blank, replace the display. If only the keyboard is not responding,
check glass touch display. If OK, replace MLB.
• If oven light does not turn on when door is opened, check oven light relay per relay troubleshooting
table. If relay voltages are OK, check door sense switch (see
CONTROLS DC POWER SUPPLY VOLTAGE TABLE
Signal Name
+12Vdc
12Vdc, 5Vdc Ground
+5Vdc
12Vdc, 5Vdc Ground
-14Vdc
Not Connected
L1 thru 2M ohm/.47 uF cap on MPB
L1 thru 2M ohm/.47 uF cap on MPB
Not Connected
NT thru 2M ohm/.47 uF cap on MPB
Not Connected
L2 thru 2M ohm/.47 uF cap on MPB
– 38 –
Min
11.00Vdc
—
4.7Vdc
—
-14.75Vdc
—
240VAC line monitor
120VAC line monitor
—
120VAC line monitor
—
240VAC line monitor
).
Door Switches
Max
12.75Vdc
—
5.3Vdc
—
-12.75Vdc