First try searching for manufacturer , change wording if no luck. If out of print try WayBack Machine at Archive.org or Scribed.com in manuals or electronics. Best of luck.
Thanks WR, but TRI-MAG has only been able to provide an external drawing of the mfsp-053 power supply (gee thanks). Scribd only came up with sales info on Dictaphone Corp. and Way Back Machine couldn't find anything. The last p/s of this type was made around 2004 and it was a custom p/s for the Dictaphone Freedom Recorder. In comparing a good mfsp-053 from our other working recorder, I found there is a zener diode
which should have -64 volts on one side and -54 volts on the other, but has
-64 volts on both sides. Trouble is, there are no markings on the diode or the circuit board to obtain its value. I tried some mathematical formulas that I found on the web to try to figure out its value, but my answers were crazy, so I probably made a mistake. It would cost $14,000 to replace this
great system and probably 2 bucks to repair it. No luck yet on obtaining a schematic for it or for an mfsp-058 power supply, which is closely related.
If I had that, I would be all set.