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Re: [tracker2] T3-135 Power issue

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  • Scott Miller
    I ve been told that at least some versions of the 135 have a programmable regulator, and doing a factory reset on the radio has fixed 5v power problems. Scott
    Message 1 of 3 , Jul 2, 2013
      I've been told that at least some versions of the 135 have a
      programmable regulator, and doing a factory reset on the radio has fixed
      5v power problems.

      Scott

      On 7/2/2013 10:17 AM, kg6bnl wrote:
      > Hi,
      > I have a T3-135 that I installed in a DR-135TP (I replaced the original
      > EJ-41U with the T3-135).
      > After installation I did not get any output on the serial port, the LEDs
      > did not come on, etc. I measured 3.5V on the 5V power line, which seemed
      > pretty low. If I feed 5V directly from the DR-135 regulator into the
      > power line on the T3, it comes up OK. The regulator is putting out
      > around 4.8-4.9V.
      >
      > Looking at the schematic for the DR-135, it seems the power for the TNC
      > module is going through a transistor (Q130, type DTA114YUA) which is
      > rated for 70mA. I measured the draw at around 40-50mA running off the 5V
      > line, and about 30mA off the transistor, so it shouldn't be exceeding
      > the spec, but maybe the transistor is bad? I measured about 3.8V when
      > the original EJ-41U is on, but it seems to work OK.
      >
      > Has anyone else seen a similar issue? I'd like to retain the ability to
      > do voice, so I'd rather not just hardwire on the 5V line to the TNC.
      >
      > Thanks in advance,
      > -Ben (KG6BNL)
      >
      >
    • kg6bnl
      Hi, There didn t seem to be any kind of programmable regulator, but I tried a reset anyways and I got the same result. Thanks anyways. I realized that I have
      Message 2 of 3 , Jul 3, 2013
        Hi,
        There didn't seem to be any kind of programmable regulator, but I tried a reset anyways and I got the same result. Thanks anyways.

        I realized that I have an original DR-135, and not a MKII/MKIII (I got it used and wasn't sure). Looking at the schematic of the DR-135 MKII, it seems they added a new 5V regulator to run the TNC, powered off the 12V rail (but still switched by the CPU). It doesn't look like they've changed the main regulator.

        I haven't wired it up yet but my plan is to get a 5V regulator with an ENABLE line (essentially doing what the MKII does) to solve this.

        -Ben (KG6BNL)

        --- In tracker2@yahoogroups.com, Scott Miller <scott@...> wrote:
        >
        > I've been told that at least some versions of the 135 have a
        > programmable regulator, and doing a factory reset on the radio has fixed
        > 5v power problems.
        >
        > Scott
        >
        > On 7/2/2013 10:17 AM, kg6bnl wrote:
        > > Hi,
        > > I have a T3-135 that I installed in a DR-135TP (I replaced the original
        > > EJ-41U with the T3-135).
        > > After installation I did not get any output on the serial port, the LEDs
        > > did not come on, etc. I measured 3.5V on the 5V power line, which seemed
        > > pretty low. If I feed 5V directly from the DR-135 regulator into the
        > > power line on the T3, it comes up OK. The regulator is putting out
        > > around 4.8-4.9V.
        > >
        > > Looking at the schematic for the DR-135, it seems the power for the TNC
        > > module is going through a transistor (Q130, type DTA114YUA) which is
        > > rated for 70mA. I measured the draw at around 40-50mA running off the 5V
        > > line, and about 30mA off the transistor, so it shouldn't be exceeding
        > > the spec, but maybe the transistor is bad? I measured about 3.8V when
        > > the original EJ-41U is on, but it seems to work OK.
        > >
        > > Has anyone else seen a similar issue? I'd like to retain the ability to
        > > do voice, so I'd rather not just hardwire on the 5V line to the TNC.
        > >
        > > Thanks in advance,
        > > -Ben (KG6BNL)
        > >
        > >
        >
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