Re: QCX microprocessor startup
开云体育Cap, The Freq Test Point is an Input* to the units own built in frequency counter. * It also reads CLK2 signal, in calibration mode.Your QCX does not boot far enough to access those. The Si5351doesn't appear to be outputting anything from what you have described in your checks so far. The next step is to find if this is the cause, or is something else preventing it. Volts & 27MHz Osc on IC1 ? Without the basics of having IC1 communicating with the MCU it will hang on startup, and not do any more. Then we can move forward, to seeing if there is activity on the I2C bus etc. Can you post clear images of your PCB Top with & without LCD, & Bottom. Alan On 30/01/2018 04:29,
capallen@... wrote:
Very much appreciate answers from far and wide. On use of my scope which seems good enough for the purpose, an old 60 MHz Tektronix, I see a very small signal on the "freq" test point but nothing on pin 8 or 10 of IC3 and with a magnifier see nothing amiss with the solder joints of IC1. Completely redid all solder joints, see voltage fine at 20 and 7 on IC2. Leaves me at a loss. Hard to believe how it all disappeared given the very straightforward testing and alignment it went through just fine.? |
Alan de G1FXB