HL2B9 - no power out

[Raj, N2RD]

Hello friends.  I have a relatively new HL2B9 that is not producing any power on transmit.  I tried using Spark SDR (FT8) and PowerSDR (Tun button, tune power set to 100).

This is a unit that flashed using Raspberry Pi.

Thanks for any tips,

Raj, N2RD

[Raj, N2RD]

Next, I hooked it up to my Raspberry Pi and ran the TEST program.  It failed all the transmit tests (22 out of 32 failed)

Raj, N2RD

[Steve Haynal]

Hi Raj,

For the Raspberry Pi tests, did you include the RF loopback cable with attenuator?

For software tests, did you follow all the setup instructions in the Quisk setup video and PowerSDR setup video?

73,

Steve

kf7o 

[Raj, N2RD]

Yes.  I did include the 30db 2w attenuator and loop back for the R Pi tests.

HLsetup sets the bias to 200.  That part worked.

I followed the Power SDR setup video.  In particular: (General Hw picked Hermes and ticked Apollo, J16 are set up, and in the General/Apollo setup both Enable Filter and Enable Tuner are ticked. All the PA settings at 38.8)

Raj

[Steve Haynal]

Hi Raj,

If HLsetup reaches the step of setting the bias, then at least the low power output is okay. It will skip the bias step if there is an early problem. I suspect there is a problem with the PA. One issue we've seen before is that a wire from T3 becomes disconnected at the PCB during shipping or handling. T3 is the large binocular core on the HL2. See the build8 notes for details on how T3 should be wired.

How do you wish to proceed? I can walk you through additional tests if you wish to try and repair this yourself. This will require a 0-30MHz oscilloscope plus your comfort with surface mount soldering rework. Or you can send the unit to me for repair and/or replacement. My address on QRZ is correct. The small priority mail flat rate box (~$7.50) works well. I'd need your HL2, N2ADR filter board plus the small board that connects the two. Return shipping and any repair or replacement costs are covered from the repair pool.

73,

Steve

kf7o

[Steve Haynal]

Hi Raj,

If you do find a broken wire on T3, please run the HLsetup with bias setup again before trying TX as I am worried your bias may be set too high.

73,

Steve

kf7o

[Raj, N2RD]

Hi Steve,

  I checked T3 by using a multimeter.  Connections 1, 2 and 3 are dead short in DC, as they should be.  Connection 4 and 5 are also connected.  so t3 seems to be OK.  

  I have USB based spectrum analyzers and oscilloscopes that cover the HF spectrum. BTW, I checked around R94 and R100 and did not see a signal there either.

 Glad to follow some steps before mailing it to you.  :(

Thanks

Raj

[Steve Haynal]

Hi Raj,

First, I'd like to see the verbose output from the hl2setup program to see details about which tests are passing and failing and by how much. When you double click on the "Test" icon, a terminal window also opens up and contains the verbose output. Just a cell phone picture of that output would be fine. You can also run hl2setup directly from the terminal:

** Open a terminal

** cd hl2factorytest

** ./hl2setup -v

The Raspberry Pi image is setup so that you can enable wifi and connect to your home network. The wired connection to a HL2 will still work. 

Now that your HL2 is programmed, you don't need to connect the jumper cables between the HL2 and RPi. Just the ethernet is required for testing.

73,

Steve

kf7o

[Steve Haynal]

Hi Raj,

I'm bringing this discussion back on list as it might help others. Even if your unit was not flashed, Makerfabs should still have tested it and it is possible to have passed the tests without the EEPROM being flashed. From the pictures you sent it looks like even the low power output is failing the test, unlike what I originally thought. Since you mentioned SparkSDR, let's do one test to check the low power output. I assume you are using one of the SparkSDR previews such as 2.0.0.7 or 2.0.0.8 from this page:

http://www.ihopper.org/radio/previews.htm

Please configure the software as shown below.

The green arrow pointing to the three ... brings up the menu.

You want to disable the PA, set drive strength to 255 and set mode to Sig.

The HL2 should be connected to the N2ADR board, but all external SMA connectors should be unconnected, no antenna or dummy load.

Press PTT as shown below. Ideally, you should see some signal via stray pickup.

With SparkSDR transmitting the signal, you should measure the following with an oscilloscope

Ground can be connected to the screw pointed to by the red arrow

Green arrow points should be ~720mV peak to peak sine wave at the TX frequency

White arrow points should be ~5.9V peak to peak sine wave at the TX frequency

Note that this is not a differential measurement, but each point measured against ground. So there should be two measurements at 720mV and another two at 5.9V.

[Raj, N2RD]

I followed your directions Steve:

  Spark 2.0.0.8 with nothing connected to the N2ADR board sma connectors.  PA off, drive 255, mode to sig.

   Nothing at all shows on the spectrum display (no stray pick up whatsoever) when I activate the ptt.  (tx led does come on)

   Voltages on the green arrow are about 425mv dc with a small ripple, white arrow 5.1v with a small ripple.  Mostly DC.  When I ac coupled it, it was close to zero.

Raj

[Steve Haynal]

Hi Raj,

Okay. It is likely a problem with the AD9866. There is a failure mode I've seen a few times when the TX output of the AD9866 goes bad. I suggest you send it to me. Once I collect a few boards, I have the AD9866 professionally replaced at a business nearby. I will send you a replacement once I receive your board.

You can also try the following:

** Check for any DC shorts on the AD9866 output. Measure with an Ohm meter DB3-4 to ground, and DB3-3 to ground. These should be ~31 Ohms.

** Check for any bad connections on the AD9866. You can inspect all solder joints with a magnifying glass or better yet, microscope. You can apply finger pressure to the AD9866 and surrounding components to see if that makes any change during the SparkSDR TX test.

** Check for any AC shorts on the AD9866 output. This requires removing L4, L7 and C49 and then retrying the SparkSDR test.

Sorry for all the hassle! You have experienced more than your share of problems with the HL2...

[Raj, N2RD]

Thanks a lot for your help Steve.  I think I had best mail it to you.  I looked at the 9866 pins using a microscope. I could not find any obvious issues.  

The resistance from DB3 Pins 3 and 4 to ground is 31.2 ohms. 

Raj, N2RD