Catalinbread Formula No 5 - JFET testing using audio probe

[Samnunn92]

Hi all,

I'm trying to debug a Catalinbread Formula No. 5 and have been using an audio probe. The schematic can be found here http://revolutiondeux.blogspot.co.uk/2012/01/catalinbread-formula-no-5.html. I get signal all the way up to and including the drain pin of Q4 (2n5457) but nothing after that and no signal out. I can't understand it as I assumed that the 2N5457 was faulty and swapped it out for a known good one but it still doesn't pass signal. Am I missing something?

Thanks

Sam

[Ice-9]

You can't have a signal on the drain of Q4 as that goes to 9v, I am thinking you mean you have a signal on the drain of Q3, if this is so then there is not a lot to go wrong past there as its is only a filter to the output jack, best check for any shorts or possibly Q3 and Q4 correct placement.