Announcement

Collapse
No announcement yet.

Montarbo 453 Echo Unit Noise issue

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Montarbo 453 Echo Unit Noise issue

    Hi all,

    I have a montarbo 453 amp that has a built in echo unit. This now makes a squeal and noise. Has anyone opened these disc units before? Any hints? It's a big 24mm nut in the end. The lid seems to be glued.
    Thanks for hints.

    Click image for larger version

Name:	echo_disc_unit.PNG
Views:	1
Size:	683.8 KB
ID:	874503

  • #2
    Start by downloadiservice manual from elektrotanya and uploading it here.

    I guess it has a motor driven magnetic drum inside, plus a couple recording heads touching it.

    Being a mechanical device, and old to boot, it must at least be dirty, needing oiling, etc.

    It must be able to be disassembled or open, just be careful.

    *Hope* itīs not riveted together making it a sealed non repairableunit, but in any case it still can be carefully opened .

    I faintly remember an *OLD* echo unit where the "tape" was thin magnetic wire wound around an aluminum cylinder and tape heads brushing against it, might be similar.
    Juan Manuel Fahey

    Comment


    • #3
      Hi and thanks,

      I cannot find a service manual for this unit, only the schematics. I have uploaded a better picture of the complete unit as well. Yes this disc "drum" must contain the heads and needs cleaning. But it's sealed and very difficult to open and I don't want to ruin it.

      See images and schematics.
      Attached Files

      Comment


      • #4
        Looking at the schematic, the record/playback module IS shown there, itīs just above the power supply drawing.
        The TL071 Op amp gets signal from mixer through pin 1 of the ŋribbon? connector at left, equalizes it and drives recording head R.
        Thansistor 2N6254 is the Bias oscillator, it also gets injected into the recording head.
        There are 2 pickup heads , 1/i and 2 ; which through connector pins 7 and 8 go back to main mixer board, "Echo Out 1/2"

        Which means thanks God there is no hidden/mystery Electronics, the mystery box only contains heads and the drum.

        IF the motor is outside and its shaft gets into the box, maybe you can inject/deposit a couple drops oil there and wait overnight for it to seep in; any original oil must be dry and crystallized by now.

        Maybe you can repair (lubricate) it without opening.

        I guess Binson sold the mechanical unit as an OEM sealed module to manufacturers such as Montarbo.

        Treat it well, itīs the little sister of Pink Floydīs awesome echo unit.
        Juan Manuel Fahey

        Comment


        • #5
          Hi,

          yes the motor is outside and in between the motor and the drum is a very big pinch roller that drives the drum. It's the drum itself that makes the squeak at a certain position when rotating. Therefor it would be great to open it and clean it but it's glued sealed and I didn't want to use too much force to open it. It works, and the echo is nice, but it has this noise. Not sure what to do now since I don't know how to even get oil in there? Maybe graphite powder?

          Comment


          • #6
            The drum must be mounted on *something*, I guess a polished steel shaft .

            Look with a good strong light and turn it a little by hand, some part must be fixed, some rotate, friction (and wear and noise) appears when one part moves against another, find that spot and inject a drop of machine oil with a long needle, let capillarity carry it where needed.

            Or maybe noise comes from motor shaft itself, or the intermediate roller.

            Moving it by hand may show "scratchy spots".

            Maybe you donīt need to open the actual drum , but take care of its mounting.

            It might have a roller bearing or a simple brass bush, in both cases with dried up lubricant.

            Show a couple close up pictures or a short YT video, both letting it run by its own motor and by hand.
            Juan Manuel Fahey

            Comment

            Working...
            X