Re: If low at O/P then trace back D2016 switching?
开云体育Hi the SAT button on and off a few times! ? Check Q2017 is switching as this will kill off the UHF RX and TX LO this should be working as RX is working can you confirm this, tx on a hand held or signal generator ? D2017 the anodes of the diodes are switched separately for TX and RX, confirm the LO is on cathode of D2016, then follow the LO through the circuit path to the TX LO O/P via Q2039 ? ? OK TP 4 to TP 7, is the supply to the VCO, pulled on by a PNP transistor in Q2015 to 18. ? OK we have VHF 1 + 2 and UHF 1 + 2, and 4 VCO, I suspect two are for TX and the other two for the RX VCO as they will probably be different frequencies! Or slit frequency operation (not sure here) or when TX and RX are used simultaneously in SAT mode? ? 73 ? Andrew ? From: Max Donoghue [mailto:ve3tmt@...] ? Went digging into the PLL board. I'm getting 3.66V at TP2003 in TX ? D2019 is switching as expected, one line high for HF, one for VHF and one for UHF. All three lines tested fine.On the underside of the PLL board, I am getting 7.9V on TP2006, but not TP2007 which leads to Q2018. ? On UHF I'm getting 7.9V on pin 2 of Q2017 but nothing on pin 2 of Q2018 check if there is something there on RX ? On VHF I'm getting 7.9V on pin 2 of Q2016 but nothing on pin 2 of Q2015 check if there is something there on RX ? ? On Fri, Jul 22, 2022 at 1:29 PM Max Donoghue <ve3tmt@...> wrote:
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Andrew Lenton