ConMed sabre 180, Service Manual

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4.5.2 Diagnostic Modes
Armed with a good understanding of the Theory
of Operation in Section 3, one can make effective
use of Diagnostic Modes in trouble-shooting
faults which disable the unit during RUN Mode.
Diagnostics are accessed in the "dI" Menu selec-
tions after entering CAL Mode, described in
Section 4.3.1.
When the Diagnostics Menu selection "dI"
appears in the Coag Power window, one may
select Watchdog Timer Diagnostics as Option 1
(dI1) in the Cut Power window, or Pseudo RUN
Mode as (dI2). Entry to the selected mode occurs
when the PAD button is pressed. Exit is only via
powering down or setting A3S1 to RST.
4.5.2.1 Watchdog Timer Diagnostics (dI1)
This section contains help in troubleshooting the
Watchdog Timer on Controller PWB (A3).
A faulty Watchdog Timer (WDT) will cause the
microprocessor to stop generating the WDTSTB
signal in RUN mode. Troubleshooting this circuit
is difficult without that signal, and setting up an
external generator and connecting it to the circuit
is time-consuming.
Diagnostics 1 mode solves that problem by using
the microprocessor as an on-board programmable
pulse generator. One may select one of three
pulse frequencies by using the monopolar foot
switch. One of the selections places pulses contin-
uously inside the normal Watchdog Timer win-
dow, while the others are too early and too late. It
is also possible to set RLYENA to verify opera-
tion of the lockup circuitry.
Since this mode is useful only with the RLYENA
flag in the reset state, "dI" will not appear in the
menu once RF has been activated in any of the
power calibration modes. On the other hand, if a
faulty WDT is detected on initial entry to CAL
MODE, Diagnostics 1 will be automatically
entered, bypassing the menu, since proper calibra-
tion may be impossible if the WDT is faulty.
An indication of the currently selected mode
appears in the Bipolar Power window. Modes are
selected round robin fashion by using the Coag
(righthand) foot switch to step up to the next
higher mode, and the Cut treadle to step down.
Table 4.5 lists the available modes.
If the WDT is operating normally, the
MACHINE Alarm Lamp will appear as shown
above until Lockup Mode 4 is selected and then
either Late Mode 2 or Early Mode 3 is selected.
After that, the MACHINE Alarm Lamp should
be bright in all modes. This indicates that the
WDT has effectively locked up, as it should.
DISPLAY MODE WDTSTB PERIOD RYLENA FLAG MACHINE LAMP
1 Normal 12.0 mS Unaffected Dark
2 Late 18.0 mS Unaffected Dim
3 Early 8.0 mS Unaffected Bright
4 Lockup 12.0 mS Set Dark*
*on initial entry to Mode 4
Table 4.5 dI1 Modes