Re: reviving my sbitx v3
开云体育Evan, I have gotten things mostly straightened out, proper voltage to R77, 5.6v to D6, etc. I still get the 3v on Q10 for the Tx signal, but Q9 just doesn't switch. The voltages on the excel sheet match the steady receive state, but things aren't
switching when the Tx is applied. Suggestions?
-------- Original message --------
From: "Evan Hand via groups.io" <elhandjr@...>
Date: 3/6/25 2:07 AM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Michael,
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The TX signal works (recieve at 0.15 volts, transmit at 3 volts).
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The pins on Q9 are marked in this photo:
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The gate (pin 1) of Q9 should be higher, and the tab (Pin 2 or drain) should be 0 volts when receiving and close to 12 volts on transmission.? It could be a failed Q9, Q10, Q101, or combination.? I would start with Q10, as it should pull down the gate
of Q9 to turn it on and supply the 12 volts to the driver stages.??
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Q101 is a 2n7002 MOSFET.? This can not be replaced with a 2n2219.??
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The above is based on not getting 12 volts on the tab of Q9.
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73
Evan
AC9TU
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-- Mike - K8MCB? |