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schematic

Discussion in 'All other topics' started by rtrg, Jun 5, 2019.

  1. rtrg

    rtrg Regular member

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    Hi guys and gals. Its been a while since I was here. I decided to rewrite my schematic for the tape transport/ record amp combination I built years ago from two donor decks, a TEAC 40-4 for the transport I rewired, and a A4300 rec/play amp from a partly working deck. I turned the deck into a bi directional deck both rec and play by adding a second head stack and switches to share the amp.

    The following schematic is a shorthand for the transport. It could apply to any 3 motor transport that uses motors with brake plates, capstan motor either 1/2 or 3 speed with switch, and 1 or two roller solenoids, preferably 110 dc. In which case a full wave rectifier will be needed for the sol. If low voltage dc 1 or 2 power supplies will be needed. A second power supply will be needed for the brake sols which are wired together. A step down transformer is used to make each motor the leading for wind and the other for trailing, and running both at lower voltage for play duty. The roller/capstan overcomes the inherent stall condition. A simple two coil 110/50 transformer will do, or one from a donor deck will do.

    Following are uploaded images of relays, switches, wiring colors. The wires follow the same colors. NO wires are connected together at a crossing over, ONLY at loads and relay wipers and NO contacts. There should be enough here to help you do this for your self. Have fun! schematic. schematic 1.

    Me again. I uploaded the entire redrawn transport schematic. Again this applies to just about any TEAC, OTARI , AMPEX ATR or similar NAB donor deck as well as using these parts to build one from scratch. The photos follows--- A total of 6 png's. All wiring shown in detail using different colors and type and destination marked.

    As far as the rec/play amp is concerned my experience is with TEAC 7" decks, 2300, 4300 and similar. I do not know if these steps apply to other brands. Starting with a 100% functional deck do the following---

    1--- de solder the wires from the 3 heads not disturbing their alignment. Some heads use connectors at the amp boards. easier.
    2--- remove 2 screws that secure head stack to chassis. remove stack as an assembly.
    3--- Find and remove connector from amp to harness and remove/unplug.
    4--- remove all screws securing amp to chassis. The amp can now be removed as a complete assembly. The 3 or 6 key function switch board will remain with amp.
    5--- Carefully dis assemble the entire chassis of all electrical parts. This will leave a complete functional
    harness on the bench. From limit switches, to motors, resistor network, capacitors, solenoids, brake plates
    still attached to motors, and any other switches or boards that were mounted to either the top or bottom of
    the chassis. It might require re soldering switches. Test the unit by reconnecting the amp before going further.
    Put deck into RECORD mode also.
    6--- Remove all 3 motors leaving everything else still connected. Remove brake solenoids but still connected.
    Be sure roller solenoid is still connected.
    7--- create a chassis box to house all these parts as a complete assembly. the 3 solenoid plungers will be
    needed.
    8--- Attach the box to the amp being sure the connector is still usable. It might be needed to remove it from
    its bracket or even make it longer, wire for wire.
    9--- Attach new assembly to the now rewired transport in the front. It might take fabricating new mounting
    brackets. The finished unit should look "normal". Make sure amp is plugged into the harness.
    10--- There will be two power cords and two power switches. Since the two units operate independently.
    The two units can be combined to operate using only one power switch and one power cord.
    11--- Re attach and re solder the head stack.
    12--- To use in "play" both PLAY buttons would be pushed, one for the transport and the other for the amp.
    For "record" the same is true, PLAY on the transport, and PLAY PLUS REC on the amp, OR only REC
    for the amp, depending on model. All the amps switches will still function. Nothing will be lost.
    This is a single directional 1/4 or 1/2 track deck. Again depending on model. The png's overlap. Hope
    this inspires you.
     

    Attached Files:

    Last edited by a moderator: Jun 5, 2019

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