Teledyne t320u Manuale Utente

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Teledyne API – Model T300/T300M CO Analyzer 
Troubleshooting and Service 
287
 
12.5.9. CPU 
There are two major types of CPU board failures, a complete failure and a failure 
associated with the Disk On Module (DOM). If either of these failures occurs, contact 
the factory. 
For complete failures, assuming that the power supplies are operating properly and the 
wiring is intact, the CPU is faulty if on power-on, the watchdog LED on the 
motherboard is not flashing. 
In some rare circumstances, this failure may be caused by a bad IC on the motherboard, 
specifically U57, the large, 44 pin device on the lower right hand side of the board. If 
this is true, removing U57 from its socket will allow the instrument to start up but the 
measurements will be invalid. 
If the analyzer stops during initialization (the front panel display shows a fault or 
warning message), it is likely that the DOM, the firmware or the configuration and data 
files have been corrupted.  
12.5.10. RS-232 COMMUNICATIONS 
12.5.10.1. GENERAL RS-232 TROUBLESHOOTING 
Teledyne API analyzers use the RS-232 communications protocol to allow the 
instrument to be connected to a variety of computer-based equipment.  RS-232 has been 
used for many years and as equipment has become more advanced, connections between 
various types of hardware have become increasingly difficult.  Generally, every 
manufacturer observes the signal and timing requirements of the protocol very carefully.   
Problems with RS-232 connections usually center around the following general areas: 
1.  Incorrect cabling and connectors.  See Section 3.3 for connector and pin-out 
information. 
2.  The BAUD rate and protocol are incorrectly configured.  See Section 6.2.2. 
3.  If a modem is being used, additional configuration and wiring rules must be 
4.  Incorrect setting of the DTE-DCE Switch. Ensure that switch is set correctly.  See 
5.  Verify that cable (P/N 03596) that connects the serial COM ports of the CPU to J12 
of the motherboard is properly seated. 
06864B DCN6314