From where I stand it looks like you have your -9 volt regulator connected incorrectly. You have it connected as 1 in, 2 gnd and 3 out. It should be 1 gnd, 2 in and 3 out. It's pinout is different to a positive voltage regulator. Regards Stuart 24/06/02 9:48:14 AM, Tal Bejerano - AMC wrote: >I draw again the PSU section. can you tell if all grounds ok? >I didn't put all components (OPamp and it components) in place, cause I need >to know if the PSU is ok in this position. >next, if it's ok, where I should connect the ground to the preamp? to the >same 0V point? >mind that I didn't connect the PSU's output caps yet. >furthermore, do you think I need mains ground? > > >Regards > >Tal Bejerano >AMC - ISRAEL > > >-----Original Message----- >From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On >Behalf Of Herbert Graf >Sent: Sunday, June 23, 2002 9:13 PM >To: PICLIST@MITVMA.MIT.EDU >Subject: Re: [EE]: Hum problem > > >> >I don't have a scope so I cant see what is going on, don't be offended I >> >have to work "blind in the dark". >> >> Tal, it looks like you are just like me, "in development" ;o) >> >> I have a tip, that may or may not work for your problem >> >> Use a common speaker, with a resistor in series, in the >> output of your power supply >> >> If you have ripple in your PSU, it can (or not) be >> determined with this simple hack >> >> In my pinball repair times, when there wasn't a scope >> avaiable (always), this was something that could find a shorted >> diode or a dried cap on the psu. Dunno if it will be of use to >> you, but here it is anyways ;o) > > Interesting trick. A trick I have used is to hook up a true RMS >meter to >the DC line, if there is ripple it shows up on the meter. It's not super >accurate but it gives a qualitative result (ie. there is more ripple then >before). TTYL > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body