Hermes Lite 2 displays TX output in thetis beta screen 4 for 1 sec then 0W REC OK

[Art Wilcox]

Hi, Art (Electronic Technician)

I purchased a Hermes Lite 2 board and filter board &  case (7/21/2023) about a month ago.

I assembled my Hermes using an anti static / grounding wrist strap.

Right out of the box, the Hermes board never put out TX power to the antenna. 

The antenna was swr 1.2 to 1  on 14,259.00 using my antenna analyzer. 

I brought my Hermes over to a friends house who has a working Hermen Lite 2.

We powered down his Hermes lite 2 and connected my complete Hermes Lite 2 unit.

My Hermes Lite 2 tested the same way - TX 0n the Thetis screen for 1 sec 2W then 0W

displayed on Thetis Beta 4 screen using tone .  The same occurred using a keyer.  

I purchased a second Hermes Lite 2  PC board (8/7/2023), swapped it out and and it works fine. 

I would like to get the first Hermes Lite 2 board working.

I performed a resistance check on the PA ic's and they measure the same as the 

new Hermes board  I purchased. 

                                                             Please CC awd...@verizon.net 

                                                              Any assistance would be greatly Appreciated.

                                                                Art Wilcox

                                                               

[Art Wilcox]

[Steve Haynal]

Hi Art,

Sorry to hear your first board is not transmitting. Given you have a second working board, we can rule out any software setup issues.

To eliminate if it is a problem with the PA, can you disable the PA and measure any low power output on RF1, the other SMA connector? Most software will have a selection to disable the HL2 PA. The low power output should be around 19dBm. 

To eliminate the preamp, can you please measure and report peak to peak TX output voltage on a scope at pin 4 of DB3 (seen in your picture) and also pin 3 of DB3. Pin 1 of DB3 is ground.

With the PA on and TX enabled in the software but with no signal (silent audio), please report the bias current. Most software will report the HL2 bias current. This should be around 200mA. For more details on the bias, see:

https://github.com/softerhardware/Hermes-Lite2/wiki/Options#calibration

One possibility is that the temperature measurement is broken on your HL2 and is reporting a false high temperature. The TX will turn off if temperature is too high. What temperature is reported? Most software will report HL2 temperature.

When trying to TX, are the relays in the TX configuration, or is the HL2 in standard receive mode?

Does swapping the N2ADR filter board from the good setup with the broken setup fix or change the problem?

73,

Steve

kf7o

[Steve Tolf]

Steve,

Did you notice the solder short on U7 in the picture? Certainly can't be good. Could that be causing the defective operation Are is seeing?

Steve, K1ST

[Steve Haynal]

Hi Steve,

I wasn't sure if that was dust or a short. But if a short, you definitely don't want it on U7 as it could cause these problems. A stiff brush or hot iron should remove that easily if a solder short.

73,

Steve

kf7o

[Art Wilcox]

I measured TP6 with Scope tektronik 2335  referenced to gnd and measured 0 vdc   so the solder ball was not shorting TP6 to +3v3. 

I checked TX current  using sparksdr software and it displayed 200mA fwd 0.0W .  PA enabled.

Idle temp is 29.5c , tx temp is 35.1 deg c

 

[Art Wilcox]

With PA disabled in thetis Beta 4 i am getting 0.0 output with a scope.   

Art

[Art Wilcox]

0.0  out on RF1 with pa disabled using tune. Measured with a scope.

[Art Wilcox]

DB3 pins 4 measured .4 vdc when i press tune it goes down to p3 vdc

 DB3 pin 3  measured   the same as pin 4 .

I hear the relay click when I press tune button in thetis beta 4  with PA enabled.

Measurements were taken with my scope scale .5 v/DIV.

Art

[Art Wilcox]

I only have 1 filter board. 
 Since i have a 50% failure rate on the Hermes Lite 2 , i didn't want to invest into another filter board. 

Ext Control      highlighted    General -> QC Control

N2ADR             highlighted    General -> QC Control 

I did not test the good board on DB3. 

Art 

[Steve Haynal]

Hi Art,

Just to double check, you see TX output when you press the tune button on Thetis beta4 with your good board?

And for measurements of DB3 pins 3 and 4, during TX do you see 300mV DC and no signal? Not sure what p3 means in your post. I see a 700mV  signal on either pin 3 or 4 during TX as seen in the picture below.

It is likely your AD9866 (U7) failed shortly after or during shipping. Do you see TX output if you use finger pressure on U7 and push it firmly into the PCB? Can you also please make sure the bottom thermal pad of U7 is well soldered. There is an access hole on the bottom of the PCB. It can take a bit more time for a standard soldering iron to heat this up, but you should be able apply solder. Finally, please check if Vop turns on during TX and is about 10.5 VDC. For the Vop test point, see:

https://github.com/softerhardware/Hermes-Lite2/wiki/Hardware

If none of the above solves your problem, please send me a private message to arrange a repair or swap within the USA.

73,

Steve

kf7o

[Art Wilcox]

 DB9   pin 2 measured +3.3vdc     pin 4 measured 1.2 vdc using a scope.

Art

[Art Wilcox]

Pressing on U7 makes no difference with TX output using Tune function. 

Art

[Art Wilcox]

Sorry , the p was supposed to be "."     (  .3vdc )

[Clifford Heath]

Are you having a one-sided conversation here Art?

I don't see anyone interacting with you, just a continuous dribble of messages containing no context.

Please keep your internal train of thought where it belongs, until you need a response, and only then if you can provide all the context required for someone to answer specific questions.

We all have our own thoughts to process and don't need constant distraction by yours. 

Clifford Heath 

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[Steve Haynal]

Please measure Vop (not on DB9) during TX. This is in the bottom right area of this picture near the op amp:

https://github.com/softerhardware/Hermes-Lite2/wiki/Hardware

73,

Steve

kf7o

[Steve Haynal]

We are both posting to the group. If you follow by e-mail, check your spam folder. Sometimes google will start putting group messages there.

73,

Steve

kf7o

[Art Wilcox]

I measured 300 mV  pins 3 and 4 on DB3   

it drops to 250 mV on tune function no signal. 

Art 

[Art Wilcox]

Yes, Vop goes to 10.5 v on tune function.

Art

[Art Wilcox]

Yes i see 4 W out on Thetis Beta 4  on the good board when i press Tune function.

Art