Can someone id this green part? Z5V 104Z 500V I think maybe it's a varistor (like the blue one in the lower-right of the image) but haven't been able to find a replacement.

Z5V 104Z 500V (varistor?)

  • 3
    \$\begingroup\$ That is a capacitor, the varistor is the blue disk on the right-hand-side of the picture. (The thingies with the single black line are \$0 ~\Omega\$ resistors :-) \$\endgroup\$ – skvery Mar 12 '17 at 20:00
  • \$\begingroup\$ What's the DC PS voltage(s) reading(s), both before and after the regulator(s)? \$\endgroup\$ – Mike Waters Mar 13 '17 at 20:55
  • \$\begingroup\$ And does that relay (KLT1C12DC24) pull in? It should make an audible click when it does. \$\endgroup\$ – Mike Waters Mar 13 '17 at 21:08

It's a Z5V dielectric 500V 100nF ceramic capacitor. Depending on how/where it's used (across the AC line or line-chassis) it may need to be a safety-rated X or Y capacitor so you will have to replace it with the correct type of capacitor if it's in one of those locations. Usually X and Y caps are film caps, but ceramics are possible too.

  • \$\begingroup\$ @Spiff -- no -- the OEM badly chintzed out. This is a 120 or 240V piece of equipment, correct? Also, what is it? \$\endgroup\$ – ThreePhaseEel Mar 12 '17 at 20:29
  • \$\begingroup\$ Can you trace out what this cap is connected to and get back to us @Spiff? \$\endgroup\$ – ThreePhaseEel Mar 12 '17 at 21:52
  • \$\begingroup\$ Why do you think it is bad? Disk ceramic capacitors are noted for having a long life (many decades). BTW, what you show in the photos is a DC power supply. \$\endgroup\$ – Mike Waters Mar 13 '17 at 16:35
  • \$\begingroup\$ I agree with @MikeWaters that the cap may not be bad- How did you test it? In any case it sounds like it might be an X or Y-cap, I can see that one end of it looks like it's attached to the AC line, can't tell if the other end is neutral or earth ground. If that's the case then you can't just use any 500V 100nF cap, it has to be safety rated for the application. \$\endgroup\$ – John D Mar 13 '17 at 17:13
  • \$\begingroup\$ @Spiff OK, you could be right about the cap being damaged. \$\endgroup\$ – John D Mar 13 '17 at 18:34

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