Servicing

If an existing test machine is in need of service, there may well be problems. It all depends on what is wrong.

Computers

The computers used to control the machines are now getting quite old and unreliable. In particular, the hard disks are getting quite flaky. It is of vital importance that the software be backed up so that in the event of a hard disk crash it may be replaced without difficulty.

The most important file is the configuration file, normally "machine.cfg", which contains details of the attached machine (including, with issue 7, the calibration factors). Also of value are all regularly used test procedures and archived data files. If this information has been saved, then I can normally rescue the situation. To be safe, however, I would recommend you keep a copy of

• the AUTOEXEC.BAT, CONFIG.SYS and NENE.BAT files in the root directory
• the entire content of the working directory (usually C:\NENEX)
• the C:\PCAD directory, if PCAD is used as a printer driver
• the C:\XTGOLD directory, if Xtree Gold is used for disk maintenance

Apart from the few USB machines, all DN products require a computer fitted with an ISA bus. Such computers are now obsolete, but there is still one manufacturer, Captec, that, I believe, still manufacture suitable computers, though I understand that some of the chips required are becoming obsolete.

Issues 6 and 7 (DOS) require Windows ME or earlier, whereas Windows software requires Windows 2000 or later.

It makes sense to try and repair the computer if possible. Do not throw out old computers, you may later regret it. Often a working computer can be put together out of two duds. The DOS software runs fast, as it is not encumbered by Windows; even a '386 will run it satisfactorily.

Electronic faults

The electronics of DN machines is usually very reliable. It is quite infrequent, but not unknown, for chips to fail. There may well be a few spare boards knocking around in various locations, or failed boards may be repaired by an expert.

A more frequent cause of failure is wires becoming disconnected in the plug connecting the cable to the computer interface card. Fortunately, this is usually easy to spot and fix.

In hydraulic machines, faults are often caused by sticking hydraulic valves and relays. This is normally within the competence of a maintenance department.

Maintenance

Screw machines rarely require maintenance and will perform for years without attention. Some early machines were fitted with grease nipples to lubricate the thrust bearings and lead screws, which perhaps should receive attention from time to time.

Hydraulic machines should have the hydraulic pump system serviced regularly, at least once a year. The oil should be inspected regularly and replaced if it is showing sign of degradation, and the filters (there is normally one on the frame and one on the pump) replaced.

Calibration

The load cell of a test machine, and the stroke transducer of a hydraulic machine, should be calibrated yearly to ensure continuing accuracy. Many calibration agencies are familiar with DN machines, but there is a procedure in the Downloads screen.

Help

If you need any help with any of the above, please contact me.

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