Noise on the FB pin is a common problem with poor layout, hence asking for a look at it.
You should not need any other bypass caps if the layout is good and the component choice likewise. Nick On 15 July 2016 22:01:39 BST, gregebert <gregeb...@hotmail.com> wrote: >Although the supply is behaving like it's under-loaded, there could be >another culprit: noise. > >I've looked at the schematic, and it's possible that the PCB layout >could >be injecting excess noise into the MAX1771. Is the bypass cap C3 >located as >close to the 1771 as possible ? I think C4 should be close to the >inductor. Be sure to check the power supply pins of the 1771 with your >scope. > >-- >You received this message because you are subscribed to the Google >Groups "neonixie-l" group. >To unsubscribe from this group and stop receiving emails from it, send >an email to neonixie-l+unsubscr...@googlegroups.com. >To post to this group, send an email to neonixie-l@googlegroups.com. >To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/093219e4-aa15-47ea-b71c-db18ad41a4eb%40googlegroups.com. >For more options, visit https://groups.google.com/d/optout. -- Sent from my Android device with K-9 Mail. Please excuse my brevity. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/04BC1E17-1E1F-489E-863C-BA2CA3DE7B77%40desmith.net. For more options, visit https://groups.google.com/d/optout.