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The 10 Ohm resistors in the diagram R14, R24, R19 and R21 should be considered as jumpers on the single sided board and can be omitted.
@ Goaty: if you really want to make a 1 to 1 comparison with your original build, you should also program your SMD version with v4.0 or 4.1.
Which could be difficult now that the chip is soldered to the board...
Looking forward to some scope images.
My gut feeling still tells me that there is something wrong with your automatic DC offset adjustment of the opamp after startup: the circuit around Q3.
This should be reflected in your waveform. When you measure it at pin 8/9 of the PIC (TP2 in the schematic), it should look something like this:
The noise on this signal is mainly coming from the scope backlight converter ( together with other EMI sources in my garage... ).
The signal in this picture will give a valid sensitivity setting between 1.5 and about 4.5 V. ( = comparator slicing level to measure the flyback pulse width ).
Below and above these tresholds, you will hear the error tone ( no flyback detected at the comparator output ) - with firmware version 4.2
With firmware version 4.1, the slicing level is fixed at about 0.5V below the max flyback voltage.
When the offset is not properly adjusted, the signal may be clipped to 5V, giving a much smaller slicing level adjustment range and less sensitivity.
The closer you bring the slicing level to the top of the flyback ( the "widest" part ), the more sensitive the detector will be for small changes.
Too close => instability.
@ Goaty: if you really want to make a 1 to 1 comparison with your original build, you should also program your SMD version with v4.0 or 4.1.
Which could be difficult now that the chip is soldered to the board...
Looking forward to some scope images.
My gut feeling still tells me that there is something wrong with your automatic DC offset adjustment of the opamp after startup: the circuit around Q3.
This should be reflected in your waveform. When you measure it at pin 8/9 of the PIC (TP2 in the schematic), it should look something like this:
The noise on this signal is mainly coming from the scope backlight converter ( together with other EMI sources in my garage... ).
The signal in this picture will give a valid sensitivity setting between 1.5 and about 4.5 V. ( = comparator slicing level to measure the flyback pulse width ).
Below and above these tresholds, you will hear the error tone ( no flyback detected at the comparator output ) - with firmware version 4.2
With firmware version 4.1, the slicing level is fixed at about 0.5V below the max flyback voltage.
When the offset is not properly adjusted, the signal may be clipped to 5V, giving a much smaller slicing level adjustment range and less sensitivity.
The closer you bring the slicing level to the top of the flyback ( the "widest" part ), the more sensitive the detector will be for small changes.
Too close => instability.
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