GaAs FET out of order

  • Thread starter Ravaner
  • Start date
  • #1
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Hello. I use 2 GaAs fet in a HF system. This assembly worked properly for several weeks and now doesn't work anymore. Before replacing these 2 transistors I would like to know how it is possible that all voltages ( drains & sources) are still correct, while the complete assembly stopped to work ?
 

Answers and Replies

  • #2
berkeman
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Can you post a schematic? Are they in the output that drives a 50 Ohm load? How much power were you pushing out to the load? Was the load ever disconnected?
 
  • #3
134
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Last transistor drives 680R and power "extracted" from this stage is probably les than µW. My question is why voltages are still the same as when this assembly was Ok.
 
  • #4
berkeman
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I think we really need at least a partial schematic and part numbers to help you. Otherwise we would just be guessing.
 
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  • #5
Tom.G
Science Advisor
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Well, a shorted inductor or open capacitor come to mind; and of course a faulty solder joint, cable or cable connector.
Just the usual suspects.
 

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