Wow and Flutter and Leader LFM39A Checks

[chriswood1900]

Whenever I set out on a project or repair the first thing I find is you seem to end up having to fix or repair the test equipment you need to do it!
In this case I was repairing and setting up an R2R tape recorder. I needed to check the speed and Wow and Flutter and the Leader W&F meter could not make sense of my calibration tapes which were from Germany and to the DIN standard There was no output on the DIN 3150Hz output and a few readings showed the output from the oscillator module had dropped from 300mV to around 18mV stopping the unit making sense of any input to the DIN standard, JIS was all OK but I had no tapes in this format.

Opening up the unit showed there were 2 grey oscillator modules one labelled 3,000Hz and the other 3,150Hz. I desoldered the 3150Hz unit and carefully opened it up to reveal a couple of sealed modules and an output pre-set, running the module from my bench PSU showed there was plenty of signal to the pre-set but negligible output wiggling the pre-set produced an intermittent output. So I cleaned it up with Deoxit and all seemed well. I could probably have found this by just adjusting the pre-set insitu but I’m always reluctant to change settings until I have found the fault.

Anyway having got the unit working again I thought it was worth doing a quick check of the calibration. In the manual it makes reference to a Wow and Flutter calibrator something I have never seen, or a test CD produced by Leader containing 55 Test tracks so I set about trying to find a copy, some time later I tracked the detailed calibration data on the HiFi engine site which can be found here:-
https://www.hifiengine.com/manual_li...r/lfm-39.shtml
but better still on a shared folder I found an image of the Leader test tracks which with the calibration data proved perfect for calibrating my unit and additionally should also be useful to others who according to other posts have found this task difficult.
https://disk.yandex.com/d/wrHNrVQibOke8Q

Good luck checking your Wow and Flutter meters.
I have attached a list of the files from Leader for future reference which with a bit of effort should be useful for many other W&F meters.
As an example if you wanted to test a W&F reading of 1% to the JIS standard you would use tracks 7-10.
One word of warning if you write an audio CD the Microsoft burning software decided to re-number the tracks which caused me some initial problems other burning packages didn't do this!

I have now got my tape recorder set up.