In a message dated 12/04/2006, cstaniger@............ writes:

I am a  junior in college and last summer I build a seismograph for a school=
 =20
project.  The amplifier and filter work great together, but when I  connect=20
the power supply to
the amp. and filter the system doesn=E2=80=99t  work. =20
Hi Charles,
=20
    It sounds like the PSU doesn't work properly.=20
=20
    Add a fuseholder and a 1/2A fuse in series with the  input winding on th=
e=20
'live' side.
    Add 47 mu F electrolytic + 0.1 mu F ceramic  capacitors between the=20
common line and both the +ve and the -ve supply rails.  Check for correct po=
larity.=20
Use components rated 16V or preferably  more..
    Check the wiring for correct connections. Note that  7812 and 7912=20
Voltage Regulators have different pin out  connections!! Check for good sold=
ered=20
joints and no 'solder bridges'.  The regulators should each have clip on hea=
t=20
sinks, electrically isolated from  each other.
    Connect a multimeter to the common output.
    On AC volts, the readings on both AC rectifier  terminals should be 12 t=
o=20
13 V.
    On DC volts, the two 4,700 mu F capacitors should  read about +16 to +17=
=20
V and -16 to -17 V.
    On DC volts, the output rails should read +12 and  -12 V +/-4%
    On AC volts, the output rails should read a few  milli volts.

My  question is, Does anyone know of any power supply schematics that would=20
work  with my amplifier and filter? =20


Make the fuse and capacitor additions to the  circuit diagram.
    _http://users.viawest.net/~aloomis/seisprea.htm_=20
(http://users.viawest.net/~aloomis/seisprea.htm)=20
=20
    Hope that this helps.
=20
    Regards,
=20
    Chris Chapman





In a message dated 12/04/2006, cstaniger@............ writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>I am a=20
  junior in college and last summer I build a seismograph for a school=20
  project.  The amplifier and filter work great together, but when I=20
  connect the power supply to
the amp. and filter the system doesn=E2=80=
=99t=20
  work.  
Hi Charles,
 
    It sounds like the PSU doesn't work properly.=20

 
    Add a fuseholder and a 1/2A fuse in series with=
 the=20
input winding on the 'live' side.
    Add 47 mu F electrolytic + 0.1 mu F cerami=
c=20
capacitors between the common line and both the +ve and the -ve supply rails=
..=20
Check for correct polarity. Use components rated 16V or preferably=20
more..
    Check the wiring for correct connections. Note=20=
that=20
7812 and 7912 Voltage Regulators have different pin out=20
connections!! Check for good soldered joints and no 'solder bridges=
'.=20
The regulators should each have clip on heat sinks, electrically isolated fr=
om=20
each other.
    Connect a multimeter to the common output.
    On AC volts, the readings on both AC rectifier=20
terminals should be 12 to 13 V.
    On DC volts, the two 4,700 mu F capacitors shou=
ld=20
read about +16 to +17 V and -16 to -17 V.
    On DC volts, the output rails should read +12 a=
nd=20
-12 V +/-4%
    On AC volts, the output rails should read a few=
=20
milli volts.
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>My=20
  question is, Does anyone know of any power supply schematics that would wo=
rk=20
  with my amplifier and filter?  


    Make the fuse and capacitor additions to the=20
circuit diagram.
    http://users.viawest=
..net/~aloomis/seisprea.htm
 
    Hope that this helps.
 
    Regards,
 
    Chris Chapman