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Re: Tracker2 not keying radio

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  • Randy Pryor
    Thanks Scott. That s the info I needed to continue the hunt. I will try to check this evening, and hopefully will find the fault. Thanks again, Randy
    Message 1 of 9 , Apr 28, 2009
      Thanks Scott. That's the info I needed to continue the hunt. I will try to check this evening, and hopefully will find the fault.

      Thanks again,
      Randy

      --- In tracker2@yahoogroups.com, Scott Miller <scott@...> wrote:
      >
      > Thar particular trace is part of the RX audio path, so it wouldn't cause
      > your PTT problem. Looks like just a bit of something in the solder mask
      > to me, but it's hard to say.
      >
      > What you need to focus on is Q1. Check at the via closest to the '0' in
      > 'C20', down toward the modular jack. That's the gate signal for Q1 and
      > it should be 5v when PTT is keyed, 0v when it's not. That signal should
      > also be present at the pad of Q1 nearest the 'Q'.
      >
      > Scott
      >
      > Randy Pryor wrote:
      > >
      > >
      > >
      > > I did some serious looking through the microscope and noticed what looks
      > > like a bad trace, but I would love to get some other opinions.
      > >
      > > I have uploaded 2 pics to the photo's section in a folder with my call
      > > sign "wb7urz". The black arrows indicate what looks like a small void in
      > > the trace.
      > >
      > > Thanks,
      > > Randy
      > >
      > > --- In tracker2@yahoogroups.com <mailto:tracker2%40yahoogroups.com>,
      > > "k7ybz" <k7ybz@> wrote:
      > > >
      > > > Randy,
      > > >
      > > > The PTT circuit is really brain dead. The microprocessor keys the
      > > gate of a low drain-source resistance N-cahnnel FET which pulls the PTT
      > > line to ground (almost). You might try reading the voltage on the gate
      > > of the FET and see what happens there during the keying. It should be a
      > > low to high for TX. There is a remote possibility that the trace from
      > > the microprocessor to the FET might be open, or from the radio connector
      > > to the fet.
      > > >
      > > > The microprocessor also controls the TX LED but off a different pin
      > > which says the microprocessor is at least doing most of its part.
      > > >
      > > > Larry
      > > > K7YBZ
      > > >
      > > > --- In tracker2@yahoogroups.com <mailto:tracker2%40yahoogroups.com>,
      > > "Randy Pryor" <Photo@> wrote:
      > > > >
      > > > > Thanks Larry for the tip. :)
      > > > >
      > > > > I will try that this evening and see what happens to the resistance
      > > value on that pin.
      > > > >
      > > > > For info the Trackers are as identical as I know how to do. I
      > > reloaded each with the same firmware build, and then flashed them with
      > > the same saved profile that I have used for months with no issues.
      > > > >
      > > > > I started with the cables as well and wasn't able to detect any
      > > issues. The radio and cables work with my Tracker2 and do not with my
      > > friends Tracker2.
      > > > >
      > > > > Unless I am missing something, this points to the suspect Tracker2
      > > as the culprit. I have not looked at a schematic so I am not sure what
      > > component(s) are involved in the PTT circuit, and will try to test them
      > > when I figure out what's involved.
      > > > >
      > > > > I also never saw the constant keying problem, so am not sure what
      > > indicators may or may not have been present during that malfunction. I
      > > have been unable to replicate that issue in my testing so far.
      > > > >
      > > > > I can see the Tracker decode packets and try to send them, but no
      > > joy on the PTT. I'm very confused at this point, so thanks for the ideas
      > > to try.
      > > > >
      > > > > Sincerely,
      > > > > Randy
      > > > >
      > > > >
      > > > >
      > > > > --- In tracker2@yahoogroups.com
      > > <mailto:tracker2%40yahoogroups.com>, "k7ybz" <k7ybz@> wrote:
      > > > > >
      > > > > > Randy,
      > > > > >
      > > > > > If the original Tracker2 was keing the radio constantly, you
      > > might want to look at the cable between the radio and OT2 and make sure
      > > there are no shorts or intermittent shorts. In this situation was the TX
      > > LED of the OT2 also on?
      > > > > >
      > > > > > If you put your Tracker2 into the loop using the same cables,
      > > then the problem does point to the Tracker2, provided the profiles ARE
      > > identical. Just to make sure, you might want to write your profiles (1
      > > and 2) to a file and load them into the other OT2 and repeat the test.
      > > This sounds less likely since you mentioned the OT2 was attempting to
      > > key properly.
      > > > > >
      > > > > > The manuals show that the PTT does not key like an HT, so that
      > > jumper should NOT be on. The voltage jumper would not matter as it only
      > > sets the voltage to pin 4 of the serial port (if used) and the rest of
      > > the jumpers do not affect keying.
      > > > > >
      > > > > > You should be able to put an ohm meter on the PTT line to the
      > > radio connector and watch when the OT2 keys. The ohm meter should show a
      > > low resistance to ground when keyed and high resistance otherwise.
      > > > > >
      > > > > > Larry
      > > > > > K7YBZ
      > > > > >
      > > > > > --- In tracker2@yahoogroups.com
      > > <mailto:tracker2%40yahoogroups.com>, "Randy Pryor" <Photo@> wrote:
      > > > > > >
      > > > > > > Hello to the group,
      > > > > > >
      > > > > > > I am helping a fellow ham get his Tracker2 set up, and am
      > > hoping someone can give me a clue to solving AN issue.
      > > > > > >
      > > > > > > The issue is that the Tracker2 will not key a Yaesu 2800. I
      > > have a similar set up using a Yaesu 1802M with a tracker2 that works fine.
      > > > > > >
      > > > > > > I configured the second tracker using the same firmware build,
      > > and settings for my digi for testing. Using the tuning and diagnostics
      > > in otwinconfig the tracker functions normally except for PTT.
      > > > > > >
      > > > > > > The Tracker decodes packets and tries to transmit with the
      > > normal lights, etc. but the radio does not key up.
      > > > > > >
      > > > > > > I have tried both jumper setting for HT with no joy.
      > > > > > >
      > > > > > > The owner of this Wayward Tracker2 initially reported that the
      > > Tracker was keying his radio continuously when first connected, and he
      > > removed all the jumpers in a shotgun approach, including the voltage
      > > jumer and thinks he may have fried something. I have looked at all of
      > > the components with a small microscpe, and could not detect any obvious
      > > damage, or leaking smoke.
      > > > > > >
      > > > > > > The tracker is powered by 8 volts supplied through the mic
      > > connector on the radio.
      > > > > > >
      > > > > > > I can put my tracker2 into the loop with the same config, and
      > > it works fine keying the radio as normal.
      > > > > > >
      > > > > > > Any troubleshooting help would be appreciated,
      > > > > > >
      > > > > > > Thanks,
      > > > > > > Randy
      > > > > > > WB7URZ
      > > > > > >
      > > > > >
      > > > >
      > > >
      > >
      > >
      >
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