probleme hf out

[georges meseciyan]

Hello everyone, I have a problem with my Hermes Lite, I can no longer output HF but it suddenly started working, nothing, even the drive of the Thetis program is set to full power. Do you have any ideas?

[Steve Haynal]

Please check the steps in this process and report back:

https://github.com/softerhardware/Hermes-Lite2/wiki/No-Transmit

73,

Steve

kf7o

[F5MAG Meseciyan georges]

 hello steve thanks for your help I would say that after having done everything that is explained in the tutorial I get 1 w hf no more I also check the quiescent currents are good I think that my final transistors are out of service you think?? 73s of F5MAG

[Steve Haynal]

I think we need more details to determine your problem. As per the wiki link, what is the power output from the low power connector if the PA is disabled? What voltages do you measure for Vpa, Vop and Vbias? Did you try to adjust the bias (not necessary as that is set at the factory, but readjustment may not be done properly)? Does one device get hotter than the other? What are the voltage or oscilloscope measurements of all LDMOS device pins during transmit? Do you observe the same problem with other software such as Quisk or SparkSDR? Is this low power output seen across all bands? Can you please post a picture (phone is okay) of the top/bottom of your PCB around the mounting hole as installation of the heat sink can damage components  J31, J32, B106 or L34. 

We need an answer to these questions as well as those on the wiki. You can copy the wiki and fill in details of what you did and saw for each step.

73,

Steve

kf7o

[F5MAG Meseciyan georges]

Hello, well ok I will look at all that and get back to you, thank you again

[F5MAG Meseciyan georges]

hello Steve 
I think I found the problem with your instructions.

[Steve Haynal]

Hi,

I'm not sure I follow what the problem was, but feel free to update any wiki page or online instructions. You only  need a free github account to edit the wiki and small edits can be done easily via a web browser.

Just to remind the community, the original goal is to have free and open community-maintained documentation on the wiki. For some reason I don't understand, some user's find this difficult and we end up with uneditable .pdf files and now even for-profit books. I think it is worth the small learning curve for those unfamiliar with a wiki if the end result is one central place for documentation.

As a general update for the community:

There is the main website: http://www.hermeslite.com/

There is the wiki: https://github.com/softerhardware/Hermes-Lite2/wiki

There is the capability to use this group not as an e-mail list but via a searchable web interface: https://groups.google.com/g/hermes-lite

73,

Steve

kf7o

[Laurent FIEVRE]

Dear all

I m not sure if my last mail was sent

As requested by Steve please found the photos requested 

No damage to the incriminated components 

We have only 1 to 2 w on mine (F5otz)

And up to 7w to (f5mag)

Same computer is used

Same software is used

In doubt 

Filter board was cross same power result 

2 pa transistor was also remplaced same result

We are thinking that the problem come ahead

Have you other points to invest eg : voltage referenced that we could make to search where come our problem?

Best 73 George and lolo

[Laurent FIEVRE]

Hello steve

Pictures made with George F5mag

No pb at all from the incriminated components 

Power output is only 1w to 2 w to mine

Up to 7w to George 

Same software and computer is use (same configuration)

Bias re verify 100ma OK

In doubt :

Filter board was swapped -> same results

2 final transistors was changed we have the same results.

We will appreciate your deep support 

We are thinking that the problem come ahead 

Have you some point of measurement to verify?

Thanks a lot

Georges F5MAG Lolo F5OTZ

On Saturday, October 12, 2024 at 6:20:11 PM UTC+2 Steve Haynal wrote:

[Steve Haynal]

Hi Georges,

Thanks for the photos. The bottom side of your board does look okay. Another common reason for low power is if B106 and/or L34 (really 0 Ohm resistor) are damaged during installation of the bolt and screw which holds the PA down. These two components are on the top of the PCB in between the two LDMOS final transistors. Please send a similar photo of this top region.

Also, please measure the RF power output from the RF1 low power connector on the back when the PA is disabled. This will bypass the PA and determine if the power from the preamp is low. You must disable the PA in your software on order to activate the low power output. There are details on how to activate and deactivate the PA here:

https://github.com/softerhardware/Hermes-Lite2/wiki/No-Transmit

73,

Steve

kf7o

[Laurent FIEVRE]

Hello Steve

Hère thé photos

[Laurent FIEVRE]

Hello steve

in the aim to progress about our problem

Pa was replaced and we must now invest ahead (pre driver)

Could you please tell us what’s the measurement that we must have pin 5 of U10 and U11

Who’s coming from u9a and u9b (opa2677)

a voltage average for measurement will be kindly appreciated because we want to solve this problem who still from the beginning.

We could also verify on pin 6 of u10 u11 if we have 

3v3

Did we consider that the command (shield) of this « relay » come from  fpga pin 11 u2b ?

Thanks a lot for your support 

Best 73 Georges and lolo

On Tuesday, October 29, 2024 at 4:45:38 AM UTC+1 Steve Haynal wrote:

[Steve Haynal]

Hi Georges,

The top components look okay.

Please measure the output from RF1 into a dummy load, the low power output on the back of the HL2, when the PA is disabled in software. This will identify if there is a problem with preamp. Please see my last post:
https://groups.google.com/g/hermes-lite/c/Bmvhv2gEimU/m/g29gIrzJBQAJ

Don't worry about the pins you mention yet. We will take it step by step. Just report the low power output on RF1. If it is low, we will look further back.

Also, please measure and report Vpa Vop and Vbias as described on this page:
 https://github.com/softerhardware/Hermes-Lite2/wiki/No-Transmit

73,

Steve

kf7o

[F5MAG Meseciyan georges]

Dear Steve

please found the measurement requested... still no power enve after changing PA

still to say that the board have a problem. please engage tue waranty process

Thank you

[Steve Haynal]

Hi Georges,

As I have said before, there is no warranty as you have modified your board for an unsupported expansion card. Users should make sure the unmodified HL2 works for the entire warranty period before considering any modification. We will help you diagnose and fix your problem on this list but I will not authorize any warranty due to the modification. 

If you see low RF output on ANT then it is impossible to see no output on RF1 (when the PA is disabled) or DB3 pins 3 and 4. You may need to adjust your oscilloscope. Please report Vpp seen on the dummy load and DB3 pins 3 and 4 as requested in the document for a 80 meter CW key down.

You can ask for help on the group which supports the AK4951 card as well.

73,

Steve

kf7o

[Steve Haynal]

Hi Goerges,

The preamp provides RF power to the PA. We need to determine if the preamp output is low. Since you see low power (~2W) from the PA it must be the case that the preamp is providing some power to the PA and is not zero unless the PA is oscillating. When you measure ~2W, is it a clean signal at the frequency you expect?

If the PA is not oscillating, I do not believe your no power output measured for the preamp. Therefore, I am asking you to repeat them with a proper oscilloscope. Since you or a friend work for Rohde & Schwarz you must have access to a good oscilloscope.

To measure power from the preamp, the PA must be disabled. I see that the PA is disabled in your pictures. The preamp power is only seen on the RF1 connector. Are you certain you are measuring power into a dummy load connected to the RF1 connector?

The preamp power will be low. It is expected to be around 17dbm. I do not recognize the power meter shown in your picture. Your meter may not measure power that low. Please use an oscilloscope to report the power for a CW transmit on 80M into a dummy load connected to RF1. This should be a Voltage peak-to-peak measurement from an oscilloscope.

Also, please provide the RF output (again Voltage peak-to-peak from an oscilloscope) for DB3 pin 4 to ground and DB3 pin 3 to ground.

These measurements are to help diagnosis and fix your HL2 in the field since it is out of warranty.

73,

Steve

kf7o

[Laurent FIEVRE]

Hello steve 

Sorry I was on business trip that why no comments from our side ….

As your Measurement requested … no power….

We have made also measurement on the DAC pin 51 and 52 with oscillo and there is nothing …

What did you suggest?

Reprogramming the fpga?

Please provide us all bitfiles factory 

I continue to say that the board IS NOT WORKING from the beginning…

And don’t says me please that I have generate EMD when had removing the coil to update it on germer 2 plus….

Because if you compare the removing coil with all that you have requested from the beginning….. where are the EMD risk? Form that you have requested or by just removing the coil?

Please…. Engage the warranty with vivo she is just waiting your green light…

Best regards Laurent and Georges