Schematic of legacy power supply

I am looking for an electrical schematic for a TRI-MAG power supply model #
MFSP-053 or an MFSP-058, either will suffice. They were found in Dictaphone Corporation's Freedom recorder logging equipment. We have been unable to record 24 of our telephone lines since the recorder went down. Any help would be greatly appreciated.
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More about schematic legacy power supply
  1. First try searching for manufacturer , change wording if no luck. If out of print try WayBack Machine at or in manuals or electronics. Best of luck.
  2. WaterRabbit said:
    First try searching for manufacturer , change wording if no luck. If out of print try WayBack Machine at or 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.
  3. If you have a zener diode with -64 volts on one side and -54 on the other, it is a 10 volt zener diode. Because the normal failure mode of a zener diode is a short, the -64 volts on both sides makes sense.
  4. Thanks, jsc. I will pick up a 10-volt zener of ample size (wattage) and install with correct polarity and let you know what happens. Yes, I have also never seen an open zener; only shorted or burned open, which means it shorted first.
  5. I purchased exact replacement 10 volt zener diode but unfortunately I still get the same readings as before on both sides
    of it. In other words, the zener is not the problem. Nothing changed. Thanks jsc, your advise was right to the point and at least I know the diode is not the problem. I'm all ears if you want to add anything else.

    try them for answers
  7. obsidian86 said:

    try them for answers

    Thanks for the reply ob.

    I have replaced the filter cap and bridge rectifier and usually do these two components as a matter of routine on any p/s.

    The failure to power-up was caused by a power fluctuation in the AC line. Normally, the power switch is activated by the user
    and a relay click is heard about 2 seconds later and then the machine starts to initialize. I get as far as the relay click, but the relay falls out and then clicks again as it tries again to start. So, I'm left with a constantly clicking relay and no start-up.
  8. Any luck with this issue. We are no longer able to find replacement power supplies so are now forced to try and repair it.
  9. In case anybody is still interested.
    I contacted tri-mag the manufacturer and you can order the replacement part MFSP-058

    The replacement part number is MFSP-058. Price and lead time is as follows:

    Price (F.O.B. Visalia, CA)

    1-5 pcs. $230.55/ea.

    Lead Time: In stock

    We accept payment by credit card (MasterCard, Visa or American Express). We also accept payment by COD or Net 30 (if credit is approved).

  10. try this site:
  11. shovenose said:
    try this site:

    Which has no entries for the power supply nor dictaphone.
  12. Check the dates guys, the Op hasnt been on here for 5 months now.
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