EMRFD Message Archive 13249
Message Date From Subject 13249 2016-11-01 18:26:12 wb8yyy_curt HYCAS Board Different than Schematic D4 ? I may be onto something, but the board (through hole version) does not seem to match the schematic in the QST article.
In the schematic the D4 cathode is attached to the output terminal of the regulator - which directly feeds the bias resistors R10, R11 etc.
On the circuit board the D4 anode seems to be floating with the output terminal, and the bias resistors are attached to the cathode -- different than the schematic.
I still need to sort this out - but it may be at the root of my biasing issues. Has this problem been noted by other builders? I suspect that I need to modify the board to match the schematic - but I will look at it again before jumping to this conclusion. But it seems to match why the resistors are biased at 10 volts while the regulator is producing 9 volts.
Any info appreciated.
13251 2016-11-01 18:48:06 wb8yyy_curt Re: HYCAS Board Different than Schematic D4 ? My mistake - board and schematic agree. I had misinterpreted the pinout of the regulator -- and this also explains my 10 volt bias onto Vcc -- I will correct this and then see what I get.