1.0  Personnel Requirements
To repair the ect eddy current system, the Technician must have training and experience in the repair of personal computers. To repair accessory cables, the Technician must be qualified in soldering and be skillful in reading circuit diagrams.
The Technician must have a working knowledge of the ect MAD 8D eddy current system basics. This is necessary so that he can make a determination as to whether or not it is functioning properly.
First it is necessary to determine whether the problem is with the computer, ect PC1 boards, or with accessory cables or probes.
To make this determination, disconnect all external cables from the ect PC1 MKII printed circuit boards which are installed in the computer. The ect MAD 8D eddy current system may have any quantity from one to four of these boards installed. These boards are identified because each board has a 9-pin and a 15-pin connector on the mounting bracket.
Make sure the computer is connected to a suitable power source. Turn ON the power. After booting, the C:\> prompt is displayed. Type MAD8D at the C:\> prompt and the MAD8D.BAT file will change the directory to C:\MAD8D\> and then start the MAD8D.EXE executable file. In a few seconds, the Copyright screen appears on the screen with the MAD8D menus down the right hand side. If a failure is observed before getting to this point in the procedure, then the failure lies with the computer hardware or software. See Section2.1 below.
Type any key to pass the Copyright screen and then type a <U> to enter the Setup Menu. All the control settings for Channels 1 through 4 appear in lines four through seven of the Setup Menu. The values listed under Bal X and Bal Y are related to the amount of correction voltage applied to balance the bridge circuitry. These values are normally within the range of +2,000 to -2,000 for frequency settings below 1 MHz and are normally in the range of +1,000 to -1,000 for frequencies below 100 kHz. If these values are very high, for example, -32,000 or +32,000, then this indicates a failure on the board that has these high numbers. Refer to Section 2.2 below.
If the Bal X and Bal Y values are low numbers, then the failure lies with the external cables or probes. If this is the case, then refer to Section 2.3 below.
2.1  Computer Failure
If it has been determined from the above procedure that a computer hardware or software failure has occurred, then proceed to troubleshoot the personal computer in the usual manner.
Problems often occur when a customer has installed additional software to the computer. Many software installation programs modify the AUTOEXEC.BAT and CONFIG.SYS files. Software that makes these changes normally retains a backup copy of these two files. If software has recently been added to the computer, then compare the AUTOEXEC.BAT and CONFIG.SYS files to their backup files to identify the offensive changes.
One common problem is the use of an EMM386 expanded memory manager. Unfortunately, MS-DOS is not compatible with expanded and extended memory simultaneously. If the customer wishes to use EMM386 with software installed on the computer, then it is necessary to add the line "EMM386 OFF" to the MAD8D.BAT file. This line may be entered as the first line in this file. Please note that it will be necessary to make this change to the REPORT.BAT file as well. After running the ect MAD 8D or Report Software, it will be necessary to type "EMM386 ON" at the DOS prompt in order to enable the 386 expanded memory manager, or to make it more automatic, add the line "EMM386 ON" to a batch file which is used to start any software that requires the EMM386 manager.
If it has been determined that one or more of the channels has failed as determined by the above procedure, then proceed as follows:
These boards are very reliable and failures of them are very uncommon. If a problem with a board has been determined, it is more probable that it has slipped partially out of its socket due to shock received during vibration. This would probably be the case if one or more boards appears to be defective.
Disconnect power from the unit and open the case. Identify the defective board. Remove the board, clean the card edge connector, and reinstall it. Reassemble the computer and begin the test process again. This may solve the problem. If not, proceed as follows:
Remove the defective printed circuit board and return it to the factory for repair or replacement. The remaining frequency channels in the system may be used during the period of time that a defective channel is not in the computer. This allows continued inspection, even in the event of a failure of one of the frequency channels.
2.3  Accessory Cable Failure
Connect accessory cables to the appropriate connectors one at a time. After connecting each connector, press <B> to balance the eddy current system. If unacceptable balance values occur after connecting one of the cables, then this is the cable which is defective.
Refer to the circuit diagrams at the back of this manual and repair the defective cable as appropriate.
3.0   Support Services
The Technician in the field providing service to the ect MAD 8D eddy current system may find it necessary to request assistance from the factory. In this case, the following information should be prepared:
1. A printout of the CONFIG.SYS file.
2. A printout of the AUTOEXEC.BAT file.
3. Date, version number, and file size of the ect MAD 8D executable software being used.
4. A printout of the screen which shows an example of the problem.
5. The exact wording of any error message which may have appeared on the screen.
Send the above information by fax or email to the factory with a clear, written description of the problem. Problems are normally responded to in two days.