Dear All,

We have been running, 3 Frame-6B and 2 frame-9E machines. In one of the FR-9E is having diagnostic alarm "<R> L63FD2H votter mismatch".

What will be the cause?

We have calibrated the particular pressure switch and restarted the <R> and <C> processor. But the the alarm state is same.

Could anybody suggest / advice, what next to be checked?

Thank you
G.Rajesh.

 

Hi,
It seems processor malfunction. Reboot all the processor and see.

 

Yes,
We rebooted <R> and <I> but the alarm state remain same.

thanks
G.Rajesh

 

We are expecting your views.

What will be the cause for the diagnostic alarm <L63FD2H> (fuel forwarding pump pressure switch)?

G.Rajesh

 

Can anybody suggest opinion for the diagnostic alarm <R> L63FD2H voter mismatch?

Cheers
G.Rajesh

 

As usual, G.Rajesh, you haven't provided much in the way of information. Is the Mark V a TMR or a SIMPLEX panel?

Why would you think that checking the calibration of the switch would have an effect on the value seen be a single processor (I'm presuming the panel is TMR)?

Have you tried replacing the TCDA card in Loc. 1 of the <QDn> core? Because, if the panel is TMR, then it's likely that input channel may be bad. Or someone has downloaded the wrong I/O Configuration to <R> (not likely, but stranger things have happened).

More information, in the original posting, and now, would be more helpful.

 

Dear CSA,

It is Mark V TMR

> Why would you think that checking the calibration of the switch would have an
> effect on the value seen be a single processor (I'm presuming the panel is TMR)?

Because problem started after the maintenance outage.

> Have you tried replacing the TCDA card in Loc. 1 of the <QDn> core? Because, if
> the panel is TMR, then it's likely that input channel may be bad. Or someone has
> downloaded the wrong I/O Configuration to <R> (not likely, but stranger things
> have happened).

We haven't try to replace TCDA nor downloaded I/O configuration to processor.

> More information, in the original posting, and now, would be more helpful.

If you need anymore details we are ready to provide.

Keep it up your good work

take care
G.Rajesh

 

G.Rajesh,

63FD-2 is a pressure switch that is connected to <QDn>, which means it's "fanned out" from the DTBA or DTBB terminal board to all three control processors. So, calibrating the switch wouldn't have any effect on a single processor's value for that discrete input.

Downloading would be a relatively simple thing to do, but it would require a re-boot of the control processor to complete the action.

You could try exchanging the TCDA in Loc. 1 with the TCDA in Loc. 2, but that would require powering down both <R> and <S>. If the problem "followed" the card, then you could definitely say it was the card. If the problem stayed in <R> the problem would most likely be the DTBA or DTBB the input is terminated on, or the cable connecting the DTBA or DTBB to the TCDA in Loc. 1.

(By the way, if you exchange or replace the TCDA card, there is NO download required, as the TCDA card gets it configuration information from the EEPROM chip in the associated processor, not from a download.)

I have neglected to ask you what the Pre-Vote Data Display shows for the value of L63FD2H.

 

CSA

Pre-vote shows zero "0" as only <R> reading "1". Sure we'll exchange TCDA and give our feedback.

Thank you

Take care
G.Rajesh

 

CSA,

Today, we came to know that TCDA loc <1> card had been replaced in 2009 with new one. So the alarm might be there from that day (we are not sure when the diagnostic alarm popped up).

If that was the case, what can we do to rectify the alarm??

take care
G.Rajesh

 

G.Rajesh,

Use the Signal Flow Diagrams in Appendix D of the Mark V Maintenance Manual (GEH-6195) to follow the discrete input signals from the DTBA/DTBB to the TCDA card.

The signal is connected to a DTBA or DTBB card.

There are three cables that take the signal to each of the three TCDA cards from each of the DTBA/DTBB cards.

A Diagnostic Alarm like this one is caused by either:

1) A problem with the TCDA card

2) A problem with the cable connecting the DTBA or DTBB card to the TCDA card

3) A problem with the DTBA or DTBB card.

Of the three possibilities, the most likely one is the first.

It's extremely unlikely that, having rebooted <R> previously, the problem is in software (unless, again, some download to <R> wasn't done correctly, but that is also extremely unlikely).

And, since you don't know when the Diagnostic Alarm appeared, and you just learned that the TCDA card was replaced in 2009, it's also likely nobody recalls why the TCDA card was replaced in 2009. I have seen many sites that swap cards for troubleshooting, and put a "bad" card back in stores.

And, cards do fail sometimes in less than 2 years.

There is one last possibility. The ribbon cable connectors and card receptacle pins of Mark V Speedtronic turbine control panels are susceptible to a kind of corrosion. Most Mark V spare cards from GE were provided with a small tube of conductive grease to be applied to the connector/pins to prevent the corrosion. It is possible, though unlikely, that one pin of the cable connecting the DTBA/DTBB to <R> is not conducting properly. Stranger things have happened. You might try unplugging the affected ribbon cable at both ends and plugging it back in a couple of times to see of that "cleans" the pins of corrosion.

If you do ultimately decide to replace the TCDA card, remember to use conductive grease at both ends of the ribbon cable. Just smear a light film of the grease on the ribbon cable connector end to cover all of the holes in the connector, then slide the connector in place. That's all that's required. To be certain the grease is as well distributed as possible, try unplugging the cable and plugging it back in a couple of times.