PA in my hl2 have only 1,8W out and smelled burnt

[Lars Hansson]

My hl2 worked perfectly fine with 7W pep to the antenna until I made a mismatch where it smelled burnt. Now I have ok reception but only 1.8W out both with the pa on and off. I assume that there is some part in the pa that needs to be replaced. Can one of you who knows a little more than me guide me on which parts in the pa-part that I have probably fried?

[Steve Haynal]

Hi,

Please post a picture of the top and bottom of your HL2 pcb. Most cell phone pictures are of high enough resolution now. We may be able to identify the problem.

73,

Steve

kf7o

[Lars Hansson]

Thank you for trying to help. When it happened I was tuning a loop antenna on my balcony

MVH
Lars Hansson

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[Steve Haynal]

Hi Lars,

The LDMOS devices for the PA, Q3 and Q4 at the top right of the first picture, look good. There is no visible damage. When you transmit, do both of these warm up at about the same rate? (You only want to transmit for 5-10 seconds when the board is outside of the enclosure.) Also, what is the bias current when you enable transmit but with no signal?

I am wondering if somehow your software became misconfigured. Is the TX gain at maximum? Do you have no band power limits for all bands? You may want to try with some other software and take a look at this wiki:

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

73,

Steve

kf7o