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Juma TRX-2 V3.00a Build 24

Juma TRX-2 Firmware, Version: 3.00a Build 24. Build 23 has been removed. As a result of a minor code move to resolve an internal low-level annoyance, I accidentally omitted the offset cancelation in the TX mode, and thus the CW/CWR/RIT offset from the RX mode was still present in the TX mode. My sin...
by 5B4AIY
13 Jan 2017 08:49
 
Forum: Juma Firmware by 5B4AIY
Topic: Juma TRX-2 V3.00a Build 24
Replies: 3
Views: 1319

Re: TRX2 test points

Hi, Whitney, Yes, you are correct, there are no pads on any of the printed circuit boards that are specifically intended as test points. Nevertheless, by examining the various schematics and their printed circuit layouts you will find plenty of places where an oscilloscope probe or a multi-meter tes...
by 5B4AIY
27 Dec 2016 11:43
 
Forum: Juma Discussion
Topic: TRX2 test points
Replies: 1
Views: 613

Juma TRX-2 v3.00a Build: 18

This build introduces an additional feature to the CW Practice Mode, and finally cures all the switching glitches. CW Practice Mode It is now possible to select the LCD scroll direction. To enter the CW Practice Mode, from the power off state, press and hold the FILTER button, and briefly press the ...
by 5B4AIY
20 Nov 2016 10:13
 
Forum: Juma Firmware by 5B4AIY
Topic: Juma TRX-2 v3.00a Build: 18
Replies: 0
Views: 462

Re: RX-1 DDS troubles, help appreciated

Hi, OK, now you have the microprocessor working it sounds as if the DDS is not working. If you connect any sort of antenna to the input of the receiver, it is sufficiently sensitive that you should hear lots of signals. If all you hear is noise, this suggests that the synthesiser is not working, or ...
by 5B4AIY
17 Nov 2016 09:59
 
Forum: Juma Discussion
Topic: RX-1 DDS troubles, help appreciated
Replies: 8
Views: 4308

PA-100D Remote Control & Status Monitoring

Build 3 - 26/MAR/2017 Build 1 has been removed, and replaced with Build 3. Whilst playing around with the remote commands I discovered that if the manual band change command was incorrectly formatted, then an erroneous display would result. This version of the firmware uses more robust error checkin...
by 5B4AIY
03 Nov 2016 17:40
 
Forum: Juma Firmware by 5B4AIY
Topic: PA-100D Remote Control & Status Monitoring
Replies: 0
Views: 610

Re: TRX2A L4 blowed

Hi, Erich, OK, that explains your symptoms. Note that R11/R12 and R23/R24 are 0.22 Ohms each, so that their parallel combination is 0.11 Ohms. They provide a small amount of DC negative feedback, but their primary function is that of providing a means of measuring the currents through the driver and...
by 5B4AIY
15 Oct 2016 06:05
 
Forum: Juma Discussion
Topic: TRX2A L4 blowed
Replies: 11
Views: 2843

Re: TRX2A L4 blowed

Hi, Erich, I am somewhat confused by your description. Let's see if we can resolve this. First, the pots must be multi-turn, a single-turn pot adjustment is far too coarse to allow for a nice fine smooth adjustment, so your damaged pot will have to be replaced with a 10-turn unit. As for your adjust...
by 5B4AIY
13 Oct 2016 11:07
 
Forum: Juma Discussion
Topic: TRX2A L4 blowed
Replies: 11
Views: 2843

Re: Problem flashing Firmware

Hi, Glen, If you loaded my firmware using the PicKit-3 and MPLAB IDE, then as the flash-writer is not present in this HEX file, you will not get it to run. As you have discovered, it is quite easy to flash the microprocessor using the 6-pin ICD header, and, as long as you are quite happy to make any...
by 5B4AIY
26 May 2016 15:19
 
Forum: Juma Discussion
Topic: Problem flashing Firmware
Replies: 19
Views: 3727

Re: TRX2A L4 blowed

Good morning, Erich, Glad that you have managed to remove the transistors without damaging the board. There are some other checks that you should perform to ensure that your replacement transistors do not fail. 1. Bias Supply If there is a fault in the bias supply, this can cause excessive bias curr...
by 5B4AIY
25 May 2016 06:54
 
Forum: Juma Discussion
Topic: TRX2A L4 blowed
Replies: 11
Views: 2843

Re: TRX2A L4 blowed

Hi Erich, Oops! Unfortunately you seem to have discovered one of the design limitations of the Juma TRX-2 power amplifier. This PA, along with many others, is not rated for continuous 100% duty cycle operational modes such as RTTY, PSK-31, Olivia, JT-65 etc, at anywhere near maximum power. Even oper...
by 5B4AIY
23 May 2016 06:51
 
Forum: Juma Discussion
Topic: TRX2A L4 blowed
Replies: 11
Views: 2843
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