Page 1 of 1

Juma PA100-D auto band tracking

PostPosted: 01 Jan 2019 16:01
by OE9DGV
My Juma PA100-D does no longer auto band tracking by frequency sense. Manual band selection is ok but since a few month the frequency sense function is not working.
Can anyone help me?
regards from Austria, Guntram oe9dgv.

Re: Juma PA100-D auto band tracking

PostPosted: 02 Jan 2019 10:58
by 5B4AIY
Hi, Guntram,

Let's see if we can find out what is wrong. If you have my version of the firmware loaded, then there are a couple of tests in the Serial Test Suite that will help. In the User Configuration menu ensure that you have the Frequency Sense mode selected. Also, ensure that the serial port mode is set to Test and that the speed is suitable, 9600 Baud is fine. Connect the amplifier to a computer with a USB/RS232 adapter and launch a terminal program. there are several available on the Internet, and something like Termite is a good choice, or Simpleterm.

Using the terminal program, enter the letter 'h', 'H', or '?' and you should see a response such as:

JUMA PA100D Firmware: v3.00c Build: 6 Date: 25/AUG/2017
Copyright: Juha Niinikoski - OH2NLT & Matti Hohtola - OH7SV
(Additional features and modifications - Adrian Ryan - 5B4AIY)
System Clock: 7372 kHz

--------------------[COMMAND TABLE]--------------------
H/? Help - (This Screen)
A ADC Channel Dump
B Alarm System Test
C LCD Bar Graph & Character Test
D Clear Factory Default Reset Counter
E Dump System & User Settings
F Dump EEPROM contents
G Toggle Frequency Sense Test On/Off
I Input Attenuator Status
J Temperature Sensor Calibration
K Buzzer Sound Test
L Write ASCII to LCD, ESC to exit.
M Write HEX to LCD, 1B to exit.
Z Divide-By-Zero Trap
-------------------------------------------------------

Ensure the amplifier is connected to a suitable dummy load, and that a suitable CW signal source is connected to the input. Key the signal source and then press the 'G' key to turn the Frequency Sense Test On. You should see a display such as:

F-Sense Test: On
160m 80m 40m 30m 20m 17m 15m 12m 10m
---------------------------------------
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
0 0 0 0 0 20 0 0 0 0
---------------------------------------
F-Sense Test: Off

To turn the test off, simply enter the letter 'G' again.

In the example above, the signal source was transmitting a CW carrier in the 20m amateur band. If you do not see a stable value in the column representing the amateur band on which you are injecting a signal, then this indicates that the frequency sense logic is not working. You can also verify this as my firmware also has a frequency counter built-in, and by selecting this display page and injecting a CW signal you can measure the frequency of the input signal to a resolution of 1kHz.

Assuming that the frequency sense logic is faulty, then you need to examine the connections between the RF input socket and the frequency sense board, as well as the frequency sense board itself and verify that the diodes and transformer are good. The RF input signal is sent from the input socket to pin 8 of J3 on the main board. This is connected via a header to the frequency sense board C1 and T1. The output of T1 is current limited by R1 and fed through two back-to-back diodes to the clipping network and R2. This network clips the input signal limiting its amplitude. The output of the clipping network is on pin 1 of J3 and this is connected to pin 2 of J5 on the main board and from there via the ribbon cable connector to pin 2 of J2 on the main board. The clipped signal is fed to an inverter, IC1 on the control board which shapes the signal and provides a logic input F-SENSE to pin 60 of the microprocessor. Ideally you would need an oscilloscope to check the operation of this logic. You can check the operation of the inverter by grounding its input (Pin 2) and checking that you have +5V at its output, (Pin 4), and then removing the ground and verifying that the output falls to approximately 0V when the input pin is taken to +5V.

73, Adrian, 5B4AIY

Re: Juma PA100-D auto band tracking

PostPosted: 02 Jan 2019 21:33
by OE9DGV
Thank´s for quick replay dear Adrian. We had a contact before and a tryed to install the new firmware. I used the usb connection cable from my KX3, it has a stereo jack, I got response from the PA but but only for few commands. Then I did not update the firmware and therefore it´s the 1.04 still.
The other thing is: After installing a 160m endfed at home for my ather Transceiver with more power I noticed, that sometimes the PA100-D was switched on with beep and error on the display. The 160m Antenna leeds in the same direction as the wire antenna where my Juma PA is connected. The distance of the 2 antennas is abt 6m. Perhaps strong signal came back to the antenna output of the Juma PA?
So, thats the situation here and I´m not a great technician and not good in soldering..
At time I´m not at home but perhaps you can give me a PM for further contacts: summer.guntram@gmail.com
I wish you a healthy and happy 2019 and tnx once more for your help.
73 Guntram oe9dgv.