Today is...
Monday, October 21, 2019
Welcome to Control.com, the global online
community of automation professionals.
Featured Video...
Featured Video
A tutorial introduction to programming using the QuickBuilder Programming Environment.
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive
Voting mismatch diagnostic alarms
Diagnostic alarms <T> core

Hello everyone, I need help finding out solution for these diagnostic alarms.
Unit is GE made, Generator drive frame 6, MK-V TMR.

I find lot of Diagnostic alarms as follows.
C 2941 Voter Mismatch (T) L63FD4
C 2940 Voter Mismatch (T) L30SG1
C 2939 Voter Mismatch (T) L94F1B
C 2927 Voter Mismatch (T) L4CT
C 2892 Voter Mismatch (T) L27MC1N
C 2891 Voter Mismatch (T) Q_QD1_CI36
C 2888 Voter Mismatch (T) L63TF2AH
C 2887 Voter Mismatch (T) L63TF1H
C 2886 Voter Mismatch (T) L63EAH
C 2885 Voter Mismatch (T) L63ET1H
C 2884 Voter Mismatch (T) L33CB2O
C 2883 Voter Mismatch (T) L33CB10
C 2882 Voter Mismatch (T) L63CS2AH
C 2881 Voter Mismatch (T) L63CS1H
C 2874 Voter Mismatch (T) L63GP
C 2873 Voter Mismatch (T) L63PG1H
C 2872 Voter Mismatch (T) L33PGO
C 2871 Voter Mismatch (T) L33PGC
C 2870 Voter Mismatch (T) L26GW
C 2864 Voter Mismatch (T) L63AD1CL

Machine is down for maintenance. All ribbon cables, arcnet, denet, ionet cables checked and are fine and firmly inserted to sockets. SDCC and SLCC cards, swapped from t core to s core,TCDA swapped from S to T but no difference in prevote data,core T reads mismatch for above mentioned logic points. TCEA and TCQC cables checked all in good condition.

Powersupply voltage from T core on Diagc shows P15 = 17 Vdc, N15 = -17 Vdc,P24 =29 Vdc, N24 = -30 Vdc. P5 = 5.02 Vdc

Where can be the fault. kindly advice

Thanks
Mambo

You've checked all the cable connections and swapped TCDA cards from <T> to <S>. I would suspect there is some problem with the power being supplied to the TCDA card in <T> (the power supply cable or the connections). You can use a voltmeter probe to check <R>s or <S>s voltages on the power supply connector pins on the TCDA cards, record them, then measure the power supply at the pins of the <T>s TCDA card. Or some problems with the IONET, which passes through the <Z> TCEA card in <PC on its way from the TCQC card to the TCDA card. Or, it could be a problem with the TCQC card in <C>.

Or, it could be the DTBA or DTBB card(s). All of the signals you listed are contact inputs; are they all connected to either the DTBA or the DTBB card, or both (since it seems you didn't list all the Diag. Alarms)? The DTBA and DTBB are common to all three TCDA cards.

When did this problem start? After the shutdown began or before? What kind of maintenance is being done? Were any downloads performed prior to this problem starting?

Have you toggled one of the contact inputs to see if it changes state at all on <T>?

What do the LEDs on the three TCEA cards look like? Do the all flash in the same sequence? Or, does <Z> flash a different set of LEDs than <X> and <Y>?

When you use the SLCC display to check the I/O Status of all the card associated with <T>, does it report all cards at I/O Status A7?

The TCQC card is not one of the cards listed/checked for I/O Status. It might be worth installing one from spares, or changing it with <S>s to see if the problem follows the card.

Have you checked all the fuses on the TCPS card in <T>?

That's about all I can think of the with the information you provided.

One thing that seems to work sometimes is to download FORMAT to <T> (in this case), and reboot the processor with the power switch in the <PD> core; <T> should boot up to only I/O Status A4/A5. Then download all (which contains FORMAT, but just answer yes to the prompt), and then when it's finished (even if it goes to I/O Status A7 during the download) reboot the processor, again with the power switch.

Let us know what you discover!

>You've checked all the cable
>connections and swapped TCDA cards from
><T> to <S>. I would suspect there is
>some problem with the power being
>supplied to the TCDA card in <T> (the
>power supply cable or the connections).
>You can use a voltmeter probe to check
><R>s or <S>s voltages on the power
>supply connector pins on the TCDA
>cards, record them, then measure the
>power supply at the pins of the <T>s
>TCDA card. Or some problems with the
>IONET, which passes through the <Z>
>TCEA card in <PC on its way from the
>TCQC card to the TCDA card. Or, it
>could be a problem with the TCQC card
>in <C>.
>
>Or, it could be the DTBA or DTBB
>card(s). All of the signals you listed
>are contact inputs; are they all
>connected to either the DTBA or the
>DTBB card, <

---Some to DTBB also

>or both (since it seems you
>didn't list all the Diag. Alarms)? The
>DTBA and DTBB are common to all three
>TCDA cards.
>
>When did this problem start? After the
>shutdown began or before? What kind of
>maintenance is being done? Were any
>downloads performed prior to this
>problem starting? <

---Unit was running with this alarms long time and when I reached site is down for a major overhaul.

>Have you toggled one of the contact
>inputs to see if it changes state at
>all on <T>? <

---NO
>
>What do the LEDs on the three TCEA
>cards look like? Do the all flash in
>the same sequence? Or, does <Z> flash a
>different set of LEDs than <X> and <Y>? <
>
----They flash same sequence synchronized
>
>When you use the SLCC display to check
>the I/O Status of all the card
>associated with <T>, does it report all
>cards at I/O Status A7? <

---All cards shows A7 state on all cores.

>The TCQC card is not one of the cards
>listed/checked for I/O Status. It might
>be worth installing one from spares, or
>changing it with <S>s to see if the
>problem follows the card. <

---TCQC from S-core was swapped with T-core before changing TCPS and was fine.

>Have you checked all the fuses on the
>TCPS card in <T>? <

---FU-4 was found blown off

>That's about all I can think of the
>with the information you provided.
>
>One thing that seems to work sometimes
>is to download FORMAT to <T> (in this
>case), and reboot the processor with
>the power switch in the <PD> core; <T>
>should boot up to only I/O Status
>A4/A5. Then download all (which
>contains FORMAT, but just answer yes to
>the prompt), and then when it's finished
>(even if it goes to I/O Status A7 during
>the download) reboot the processor,
>again with the power switch.
>
>Let us know what you discover! <


---Dear CSA,

Thanks for your help and advice. Following are my findings.

I found no voltage at JP plug at TCDA -3 - QD core, I checked the fuse FU-4 was found burst on TCPS card.

I installed new TCPS card in the T core, I didn't connect to TCDA card of QD core and checked the voltage at the JP plug and found there is -N16.25, P16.21, P5.128 and P27.08 VDC at the JP plug.

I switched off T core power supply, and when I inserted the power supply plug JP on TCDA card-loc-3 and switched on the power, I checked diagnostic alarms showed back on T core same alarms repeated.

When I checked voltages at JP plug of TCDA-3 I find P15 and N15 missing again. P5, P24 are normal.

Removing the card out FU-4 was burst again, and when I removed the fuse and checked between two points of FU-4 holder points I find continuity!!!

TCDA on T core is fine as I interchanged to S and it work fine for S core.

Any further checks as to what can cause this?

Thanks,

Mambo

Reading between points on a printed circuit card can be very misleading; lots of parallel paths can exist.

I would suspect that if the card is not the problem then there is some problem with the cable insulation and that when it's connected to the card there is a short somewhere. Have you tried to check the cable working backwards from the TCDA connector end to see if there's a problem with the cable?

That's about all I can think of right now. Most people don't have spare cables, but if you do, I would suggest trying to use a new cable temporarily (just run outside the cores) to see if that's a problem.

Let us know what you you find!

Dear CSA,

Thanks for the advice.

I had checked each wire of cable respect to ground from both ends but cable is fine. Once I get another TCPS card I will take extra precautions and will come back on this issue again.

Best Regards,

Mambo

It may seem like a stupid question but when you say you checked the ribbon cables how exactly did you do this?

I had a similar problem with a TMR Mk V on a LM 2500 G/T it turned out to be a faulty Ribbon cable on which 1 core had become detached (internally) from the Plug and whilst it looked OK with a visual inspection it failed on a Point - Point (continuity test) ...worth a try.

Sandy