Repair Log:
I was given a Bruel & Kjaer 2144 Dual Channel Real Time Frequency Analyzer to repair. The unit would not power up and I could not find any schematics. I checked the removeable mains to 12V power module and this was OK I then started to look at the dc-dc converter board. I could not find any immediate component fault so I looked at how the dc-dc converter was actually triggered 'on'. I found that the trigger voltage was derived from the CPU memory backup battery which, as the unit had been in storage for a while, was flat. The power-on trigger operates through an opto coupler on the dc-dc converter board. You can access the positive terminal at the top of the 3.6v battery (see photo) so the unit was 'jump started' by injecting a small current (c.30mA) onto this terminal until the battery had sufficient charge to operate the power-on opto. The unit powered up but because the CPU memory battery was flat, the program software was lost and as I don't have any software the unit can't be used at present. I later replaced the CPU memory battery as it would not hold charge.
Software:
I contacted B&K in UK about obtaining software and whilst they were helpful, they could not find any software for this model in their archives. I followed up on B&K's response to ask whether it was acceptable to obtain a copy of the software from another user (i.e. no copyright / IPR issues). B&K checked and confirmed that this would be OK. I don't know the details of the software that is available for this unit. I would like to restore its functions as a basic low frequency analyser. Perhaps the blog contributors can help me find some software to make this unit operate.
I can't help you with software but wanted to say 'good troubleshooting'. Hope you get it going.
If it's the software described in the attached PDF then it's not very exciting, MSDOS & LPT ports, yuk.