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TOPIC: Sunsdr2 DX without VHF power

Sunsdr2 DX without VHF power 14 May 2022 16:01 #1

  • Jose232
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Hello, I am having problems with a SunSdr2 DX in VHF, I have stopped having power in the antenna, when you press PTT there is consumption since in RX it is 0.9Amp and in transmission 3.1Amp, but neither the internal meter nor the external meter measure power, I have tried it with both the Expert2 and 3 versions without results.

I have restored all the parameters to default and it is still the same, what I do notice is that I do not hear any relay when I press the PTT and that is quite strange, it is a device that is about 6 months old and I have hardly used it on VHF.

A greeting and I hope that someone helps me with what is happening, thanks.

Excuse my english...
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Sunsdr2 DX without VHF power 18 May 2022 11:13 #2

  • EI9HEB
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Looks like you have a faulty relay.
Easy fix if you know how to solder SMD and have tools for it.
How do you VooDoo?
Last Edit: 18 May 2022 11:15 by EI9HEB.
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Sunsdr2 DX without VHF power 18 May 2022 14:13 #3

  • Jose232
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Hello EI9HEB, first of all thanks for answering, and the truth is, I'm also suspicious of the relay... on the other hand, I have tools for SMD, but I don't have any information about it, like which of the relays it may be of the several that it has, what dude, where to find it...

And we are talking about equipment that is 6 months old and has hardly been used on VHF.

And with all the situation in which we are involved, I would not know where to send it since it is supposed to be under warranty or that a colleague has the information, if something similar has happened to him...

Greetings and thanks for your interest.
Last Edit: 18 May 2022 14:14 by Jose232.
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Sunsdr2 DX without VHF power 18 May 2022 15:54 #4

  • N8SDR
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Jose232 wrote:
Hello EI9HEB, first of all thanks for answering, and the truth is, I'm also suspicious of the relay... on the other hand, I have tools for SMD, but I don't have any information about it, like which of the relays it may be of the several that it has, what dude, where to find it...

And we are talking about equipment that is 6 months old and has hardly been used on VHF.

And with all the situation in which we are involved, I would not know where to send it since it is supposed to be under warranty or that a colleague has the information, if something similar has happened to him...

Greetings and thanks for your interest.

Reach out to Roman
if it is still under warranty
send him an email:
73 Rick
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Sunsdr2 DX without VHF power 18 May 2022 16:38 #5

  • Jose232
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Reach out to Roman
if it is still under warranty
send him an email:[/quote]

Ok, thanks for the suggestion... I have sent an email to Sunsdr, to the attention of Roman, because I don't know his email.

As soon as they answer, I will inform you what the possible solution is.

73
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Sunsdr2 DX without VHF power 29 May 2022 16:03 #6

  • EI9HEB
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Hi Jose
Do you have an oscilloscope it will be very helpful to diagnose?
I was fixing my one a while ago.

1. Check the RX capability on VHF.
If yes Solution: proceed to step 3.
If no – either no reception or with big attenuation. Solution: Replace K4_ANT relay or antenna connector А1 (if relay replacement wasn’t enough).

2. Go to VHF 2М and select А1 connector (connect 50 Ohm dummy load).
Check the signal on the input (1st pin) of the amp module RA08H1317M (covered with the shield with screws). Signal level on the input contact should be 1.5 V pk-pk (+5...+8 dBm) or higher with max Drive level.
Note: transmit for 3-5 seconds. Do not transmit for a long time. If yes – there is a signal on the amp input.
2a. If no check the DAC out for VHF and HF if there is no signal on DAC OUT for VHF and HF
solution replace K1_A4
Go to 2. if no: check the SGA4586 marked on the screenshot under the shield.

Solution: proceed to step 3. If no - there is no signal on the amp input
Solution: Replace K1_PA relay. Check step 1 once again.

3. Check the signal on the output (4th pin) of the amp module RA08H1317M (covered with the shield with screws).
Signal level on the output contact should be around 30-50 V pk-pk (35-38 dBm) with max Drive level.
If yes - there is a signal on the amp output. Solution: Check the signal on the LPF output, power meter, on the 3rd pin of K1_ANT relay (switches TX/RX modes on VHF). Replace LPF components or power meter or K1_ANT relay.
If no - there is no signal on the amp output. Solution: Replace amp module RA08H1317M.

How do you VooDoo?
Last Edit: 29 May 2022 16:07 by EI9HEB.
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The following user(s) said Thank You: Rome, Jose232

Sunsdr2 DX without VHF power 29 May 2022 18:20 #7

  • Jose232
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Hi EI9HEB, first of all thanks for all the information, which is similar to the one that Rome had sent me by mail, in principle everything points to the K1_A4 relay, and I have already ordered two units from mouser, by the time the material arrives and do some tests, I'll comment, thanks for the help.

All the best
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