I suspect they will "solve the problem" but at considerably more cost than two small capacitors which should have been there in the first place. ...
Nick On 30 March 2015 12:47:54 GMT+01:00, Kiran Otter <[email protected]> wrote: >Nick, > >Would replacing the 7805 with a 'non-isolated dc/dc converter' like Jon > >suggested solve the problem too? I ask because I was going to try the >Traco TSR 1-2450, or the Murata part (though I'm not sure it will fit.) > I >ordered both. > >I'll get my scope out today and see what I can see. > >Kiran > >On Monday, March 30, 2015 at 6:33:57 AM UTC-4, Nick wrote: >> >> Just to re-iterate - solder a small 100nF capacitor between pins 1 & >2, >> and another between pins 3 & 2, preferably on the underside of the >PCB >> directly to the 7805's solder pads. >> >> The symptoms you are seeing are almost certainly nothing to do with >the >> heatsinks etc - I'd put good money on this being a very common & >classic >> issue with 78xx & 79xx linear regulators whereby they break into VHF >> oscillation and over-heat. This is extremely well documented and the >> manufacturer's datasheets all say that the two suppression caps are >not a >> "nice to have" but are essential. Most of the datasheets actually >specify a >> 330nF input capacitor (between pins 1 & 2) but a 100nF works well >too. >> >> Missing out these two capacitors is a basic error. >> >> Nick >> >> > >-- >You received this message because you are subscribed to a topic in the >Google Groups "neonixie-l" group. >To unsubscribe from this topic, visit >https://groups.google.com/d/topic/neonixie-l/_OjC4E__J_M/unsubscribe. >To unsubscribe from this group and all its topics, send an email to >[email protected]. >To post to this group, send an email to [email protected]. >To view this discussion on the web, visit >https://groups.google.com/d/msgid/neonixie-l/b4012849-acd5-4630-ad73-62ea6ee8c803%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 [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/C8631BFA-F7F3-4F06-BAD2-9F29808DC148%40desmith.net. For more options, visit https://groups.google.com/d/optout.
