Replacement of a portastudio 464 transformer, what are these characteristics?

Discussion in 'TASCAM DIY Repairs and Mods' started by wire31, Feb 7, 2019.

  1. wire31

    wire31 New Member

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    From:
    Dirty south of France
    Gear:
    Tascam portastudio 464
    Hello,

    What are the voltages of the transformer secondary windings of the Tascam portastudio 464?
    If someone has the service manual this mixer or diagrams more accurate than the user manual, it would be perfect!

    Thank you in advance.
  2. SkywaveTDR

    SkywaveTDR Active Member

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    In the service manual it does not always give you the voltages but they can be approximated by the filter capacitors on the DC filter. A full wave bridge rectifier will give you when filtered a DC voltage 1.4 tines the AC voltage input to it. So if a filter cap in the circuit is 35V then the output voltage will be 35/1.4 about 25Vac. Now designers put caps in that have a margin of safety so if a DC supply uses 35V caps then the DC applied to it would be in the 28-29 Vdc area- then going back you will find that the output of the transformer is 20-21 Vac. This is all basic DC theory as learned in the start of a Technicians training. There is usually no need to have transformer outputs unless someone has done something terribly wrong to the deck. It is not the AC voltages you need to know but the appropriate DC outputs that have to be there. Many times those are given. If you work on the deck you will need a service manual- there is no way around it.
    wkrbee likes this.
  3. wire31

    wire31 New Member

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    From:
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    Tascam portastudio 464
    Thanks you for the answer,
    After the transformer (53200613), I have 3 oupouts: one wire link to the chassis and two to the glass fuses f1 and f2: t1l250v. The bridge rectifier d1 is a s2vb10 and the filter capacitors c1, c2 and c3 is 25V 3300µF. The other capacitors are 16v on power pcb.
    (and also: u2, u3 and u4: n4212 q1: d1913 q2: b1247 and q3: a1015 J1: 7812, j2:d1913 j3: b1274).
    It's mean: the oupout would be around 20Vdc and the oupout transformer is 20/1.4 about 14-15Vac? is it for both oupouts link to the glass fuses?
  4. SkywaveTDR

    SkywaveTDR Active Member

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    From:
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    I have looked and the service manual is not in my files and very hard to find. Most transformer that are center tapped will have like voltage coming from each section. You can see what kind of of transformer that is in the schematics. Presently I have checked all my sources and no one has a service manual. If you have the service manual you will be able to fix the unit. Without it will be much more difficult. Maybe one of the other guys at Tascam have the SM as this model came out many years after I left.