Teledyne 6200E - Sulfides Analyzer - Manual (Page 254)

TROUBLESHOOTING & REPAIR Model 6200E Instruction Manual
254 M6200E Rev: A1
A voltmeter should be used to verify that the DC voltages are correct as listed in Table 11-5. An
oscilloscope, in AC mode and with band limiting turned on, can be used to evaluate if the supplies
are excessively noisy (>100 mV peak-to-peak).
Table 11-5: DC Power Supply Acceptable Levels
CHECK RELAY BOARD TEST POINTS
From Test Point
To Test Point
POWER
SUPPLY
VOLTAGE
Name # Name #
MIN V MAX V
PS1 +5 DGND 1 +5 2 +4.80 +5.25
PS1 +15 AGND 3 +15 4 +13.5 +16.0
PS1 -15 AGND 3 -15V 5 -14.0 -16.0
PS1 AGND AGND 3 DGND 1 -0.05 +0.05
PS1 Chassis DGND 1 Chassis N/A -0.05 +0.05
PS2 +12 +12V Ret 6 +12V 7 +11.8 +12.5
PS2 DGND +12V Ret 6 DGND 1 -0.05 +0.05
11.5.5. I 2 C Bus
Operation of the I 2 C bus can be verified by observing the behavior of the LED labeled D1 on the
relay board in conjunction with the performance of the front panel display. Assuming that the DC
power supplies are operating properly and the wiring from the motherboard to the keyboard as
well as from the keyboard to the relay board is intact, the I
2 C bus is operating properly if:
• D1 on the relay board is flashing or;
• D1 is not flashing but pressing a key on the front panel results in a change to the display.
If the display is locked up or if the analyzer is not booting up at all, the I 2 C bus may be the cause.
Contact customer service if you suspect a problem with the I 2 C bus.
11.5.6. Keyboard / Display Interface
The front panel keyboard, the display and the keyboard/display circuit board can be verified by
observing the operation of the display when power is applied to the instrument and when a key is
pressed on the front panel. Assuming that there are no wiring problems and that the DC power
supplies are operating properly:
• The vacuum fluorescent display is working properly if, on power-up, a “-“ character is
visible on the upper left hand corner of the display.
• If the analyzer starts operation with a normal display but pressing a key on the front panel
does not change the display, then there are three possible problems:
• One or more of the keys is bad
• The interrupt signal between the keyboard circuit and the motherboard is broken due to
a cabling problem or
• The keyboard circuit is bad.