From: ehsjr@verizon.net   
      
   On 2/25/2024 1:01 PM, Cursitor Doom wrote:   
   > So - in the case of a linear power supply - the rectified output of   
   > the transformer typically goes straight to a big old storage cap for   
   > smoothing purposes. My question is: how much ripple should I expect to   
   > see across that cap if all's working well? I have to say I'm seeing a   
   > *lot* of ripple on this cap in a Marconi RF signal generator and it's   
   > finding its way to the RF output, which of course should ideally have   
   > zero ripple on it. The aforementioned cap tests fine WRT ESR and   
   > capacitance in-circuit, I should add.   
   >   
   > Thanks,   
   > CD.   
      
      
   Prior to the regulator circuit, the ripple voltage   
   depends upon current drawn for a given supply at a   
   given frequency. The higher the current drawn, the   
   greater the ripple for your supply.  So one possibility   
   in your generator is that too much current is being   
   drawn i.e. a defect in some circuit "downstream" of   
   the bridge/cap.   
      
   Depending on what follows the diode/capacitor supply you   
   may have a regulator failure.  Regulators hold the voltage   
   at some specific value, thus they remove ripple.  Voltage   
   measurements usually reveal which regulator is failing to   
   provide the proper output voltage. Again a defect downstream   
   may pull the voltage down.  Without a manual/schematic its   
   harder to diagnose - but it is still possible.  And I read   
   somewhere that manuals are available. See the url posted   
   below - it may help.   
      
   Next - perhaps the ripple really isn't excessive.  By that   
   I mean it may be within spec for your generator. You may   
   find this site helpful:   
   https://groups.io/g/Marconi-Test-Instruments   
      
   Good luck. Let us know whe you fix it!   
   Ed   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)