I have a simplex MARKV system installed and it was working fine. Suddenly it has started showing the following alarm:

T1 1 1360 TCQA P125-N125 Overvoltage

I checked the incoming AC voltage to PD core and it was ok. 132VDC to <R>and <C> from <PD> core is also being supplied. I haven't checked TCPS and TCQA card yet. Reading on DIAGC/TCQA1GB/Power supply data/F1BBA&F1BBB is:

P5v = 4.91 (stable)
P15a = 13.40 (stable)
N15a = -15.71 (stable)
P15b = 13.41 Vdc (stable)
N15b = -15.72 (stable)
P125 = Varies from 67 to 46 Vdc
N125 = Varies from -84 to -70 Vdc

Power data on TCCA card is stable for P125 and N125.
Secondly, whenever I try to access CARD IDENTIFICATION module (after authentication) I receive two further diagnostic alarms:

09 DCC DPM Invalid destination address
05 DCC No que server for destination

These two alarms reset after some time.

Kindly somebody answer me asap...

 

Judging from the data you sent, there appears to be a problem with the TCQA card or the 125 VDC voltage sensing of the card.

Have you recently experienced a ground somewhere on the 125 VDC system? Has the weather changed recently, such as in has a rainy season started?

Have you applied a light film of conductive grease to all the connectors (ribbon cables and power cables, etc.) in the Mark V panel? It might just be that a high-resistance connection has developed because of some corrosion on some pins/receptacles. Sometimes just unplugging and plugging the cables a couple of times will help with such a problem. But, if the environment at the site is humid it's a good idea to power the panel down and try the above for all cables and connectors and then apply a light film of conductive grease and then power the panel back up and check everything out.

The easiest way to apply the conductive grease to ribbon cable connectors is to apply a thin, light coating to the female end over the pin sockets and then push the connector down over the pins. Too much grease is usually worse than none at all; moderation is a good thing when applying the conductive grease.

While you're in the panel, if it's dusty, use a non-conductive vacuum hose and attachment (they can usually be purchased from safety houses or computer supply stores) to clean the cards and components in the panel. Dust and humidity are the worst enemies of electronics, followed closely by heat. This should be a regular maintenance activity (every couple of years or so depending on the cleanliness of the site).

Have you tried replacing the TCQA card? (Note, when you do this you will likely need to recalibrate any LVDT feedback signals.)

CARD_ID.EXE will query the Mark V panel for every card that might possibly be installed in the panel; hence the Diag. Alarms you are experiencing when you try to run the executable. CARD_ID is something of a misnomer as it really reports the PROM revisions of the PROMs installed on the cards, not the revisions of the cards themselves.