GE MARK IV control system

  • Thread starter Mark IV maintenance personel
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Mark IV maintenance personel

Mark IV turbine control system "remote communication link failure- drop No 236 Signal name L30A236".

Mark IV contol system has two operator consoles, one at Local and other one remote control room, whch is linked via media acess unit, DS 3820 <MAUI>.

Now at remote Operator terminal all display dynamic field values are Zero. Remote <C> HMPJ initilization done, I'm OK green LED OK, but Bottom RED LED Off (Analog input fail). HMPJ replaced still same. RAM_ROM TEST COMPLETE printed while booting.

In HLNE CONFIG, PEND RED LED continously flashing.
In local <R>, <S> <T> <C> all OK.
In Local no diagnostic alarm.
L3LNKFD1 and L69SEREM are High and alarm drop 236 "Remote communcation link failure.
How to reset this alarm.

I looking for help from Mark IV/V expert/user to fix and solve the problem.
When did this problem start? Suddenly, or after some rain storm or excessively hot and/or humid weather conditions?

From the description it sounds like the problem is not necessarily in the communications modules at either end of the CSF link, but rather in the link itself.

Have you verified the interconnecting cable is good? Some systems used a serial CSF (Control System Freeway) and some used a twin-axial cable for the CSF. Many times the twin-axial cable connectors were not properly terminated in the field. The pins in the connector had to be crimped on the conductors of the twin-axial cable and it was quite common that they were either not properly crimped or that they were crimped at all.

The twin-axial cable had a very specific capacitance-per-foot rating, so if it was damaged and replaced with something which was not compatible that could be the problem.

mark Iv maintenace

This problem started after external power supply surge ; Surge cause CRT module went blank after repair CRT display resumed. TWIN axial cable used in CSF.Cable Connector end continuity checked found OK.

HMPJ , HVDB,HAIC cards were replaced to solve the problem, but no progress.

First HMPJ initialization not proper even with new card.( RED LED continuously OFF, it indicates analog signal not available)

Second How to rest bus Hog in the Local<C>. In local <C> HMPK in slot 2M, BHOG, TST Red light ON permanently (ie) bus Hog LED signal are present. How to rest this condtion.

Third in Remote <C> HLNE card in slot 1F red light PEND and CONFIG are continuously FLASHING. DIAG light OFF; I’M OK green light ON.

Also REMOTE Media unit access card<MAUI.R> DS 3820 MUAD CR20, CR22, CR 21 red-light continuously FLASHING. Cable A, B OK light ON.

Thankyou for u r reply.

further looking u r advise to solve the problem.