Diagnostic led's on MARK V


The meaning of the flashing (or solid) LEDs on the various Mark* V cards changed regularly with new PROM revisions. To my knowledge there was never any kind of description or legend to indicate what they meant for any PROM revision. Effectively, they were used as a diagnostic tool by the printed circuit card-, firmware- and software designers and there was no standard that said they had to be returned to any "typical" flashing indication.

Presuming you have a MArk* V TMR control panel, many of the printed circuit cards (the 8-1/2" x 11" cards) that have LED bargraphs are triplicated in the control panels. For example, there are three TCEA cards in the <P> core, and when there are NO Diagnostic Alarm conditions ALL of the LEDs on the three TCEA LED bargraphs should all blink at the same frequency and in the same manner--which means the three TCEAs are working correctly.

For another example, the LED bargraphs on the TCDA cards in Locations 1, -2 and -3 of the <QDn> discrete I/O core(s) should--when there are no Diagnostic Alarms--blink at the same rate (frequency) and in the same order indicating no abnormal problems.

Again, this should be true of any card that is used in multiple locations in the Mark* V turbine control panel.

When I say Diagnostic Alarms, I'm generally referring to alarms appearing in the Diagnostic Alarm display on the <I> or GE Mark* V HMI. BUT, it can also refer to alarm conditions annunciated on the LCC/SLCC keypads of the <C>, <R>, <S> or <T> cores. And the Mark* V Maintenance Manual tells how to use the LCC/SLCC keypad to view alarms on the LCC/SLCC LED display.

The Mark* V turbine control panel is a very tightly synchronized (in terms of scan times/rates and execution) turbine control system. All of the LEDs on similarl printed circuit cards (even cards located in different cores, for example the TCQA cards in <R>, <S> & <T>) should all blink at the same rate (frequency) and in the same manner when none of those cards is experiencing any Diagnostic Alarm conditions.

If you can describe the problems you are having, we can probably suggest some steps to take. But, if it's just some kind of secret decoder ring for the LEDs of the LED bargraphs--there isn't one in existence in my experience.
Thank you for the information.

We some times get a trip with the alarm of "communication loss R and C processors" I will upload a photo later. And the leds are in the state of the picture I uploaded erlier. When its normal only the first led on the left side is flashing. We apply some dielectric grease on the comm cables on the mark V and that seem to stop the trips. But we wanted to know about the leds