Re: LF: Softrock RX divider IC problem, unexpected frequency out

[M0FMT <peteg8fmt@gmail.com>]

Hi all

Compare and contrast the schematic (attached ) of Jim M0BMU’s MF/LF Softrocks I have built these with no issues. The V6.2 had two dual flip/flops /4 and /8 I have made them using just the /4 because of the rocks available for no other reason l.e. like yours so there is hope your kit will work as well. I see you have had advice on the Softrock 40 group the font of all knowledge Softrock who I think have said more less what I have. The schematic is well proven that should give confidence there is no fundamental design problem, so look for construction issues.

Good luck 73 petefmt

On Fri, Jan 26, 2018 at 8:11 PM, M0FMT <peteg8fmt@gmail.com> wrote:

Hi all

The important thing is that the frequency is correct (which it is) the wave form looks OK and the peak to peak volts are enough to drive the flip/flop There is a bit of second order distortion on the MF LO but it is not an issue.

I personally would conclude the problem is with the flip flop however try doing the same at the divide by four LO output check you have two outputs and if you can compare the phase difference it should be a 1/4 cycle difference i.e. 90 degree shifted. The level should be similar to the levels already seen on the first oscillographs. but it can be lower and still work OK i.e. over the threshold to trigger the multiplex chip normal TTL levels tolerance.

Good luck 73 petefmt 

On Fri, Jan 26, 2018 at 7:36 PM, Chris Wilson <dead.fets@gmail.com> wrote:

 I just completed two scope measurements at R17 to pin 3 of the divider
 IC. One of the faulty LF Softrock, and one on my MF one that works
 fine. the resultant wave forms are quite different. But I am not
 clever enough to say if they hold the clue, so will post them here.
 Thanks again.

Faulty LF oscillator or divider first

http://www.gatesgarth.com/R17-to-pin3.jpg


Working MF Softrock, same place

http://www.gatesgarth.com/mf-R17-to-pin3.jpg

--
Best regards,
 Chris                            mailto:dead.fets@gmail.com

Softrock_136_500.pdf
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